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 8. Wet weather setup *  9. Quick Chassis Setup Guide *
 10. Invader Chassis Setup Manual *  11. TonyKart Chassis Setup Manual *
 12. Chapter 2: Front End *  13. How Fast Do Karts STOP!! *
 14. KART SETUP By 15 Times Australian Champion, John Pizarro *  

Wet weather setup

Front wheels :- may be moved out as far as possible during wet weather, and if you have a caster adjustment on your kart you can also adjust it to the maximum, this should help reduce any understeer. Also if you have wet weather extender hubs use them, they are very affective as they allow you to run your wheels wider than normal.

Rear wheels :- The rear of your kart is also a critical part of set-up in the wet. Some drivers like to bring their wheels in as far as they can to obtain maximum traction, however taking them in too far binds up yhe rear of the chassis giving the front of the kart too much grip because in actual fact you have widened the front by even more making the kart unbalanced. Moving the rear wheels in about 30mm is about right

Tire pressures :- should be increased by 10 to 15 p.s.i. in the front and 15 to 20 p.s.i. in the rear depending on how wet the track is. This can differ from person to person, I prefer to run lower pressures as this has more rubber on the track and in turn slightly more grip, but test the two tire pressures against each other to find which is the best for you and your kart.

Seat Stays and Seat position :-Remove any you have on your kartto allow the chassis to flex more.You don't have to take them right off just undo the seat bolt and put a ziptie through it.
If you have time raise your seat by around 20mm. This will lift the centre of gravity giving you more traction. Moving the seat forward will also help.

Gearing :-In wet conditions your engine is running at lower revs so you shuold add a couple of teeth to help you pull out of the corners.

Side Bars :-Loosen them off as this will also help your chassis to flex more thus resulting in more grip. Tie rod ends :-It is a good idea to give your kart about 5mm toe out in the wet as this helps wash the water away. Do not forget to readjust the front alignment of the kart when racing goes back to a dry track

Engine :-Always cover the airbox with an airbox rain cover to stop water going in your engine. Failing to do this causes two things; firstlyyour engine has a good chance of simply stopping on the track when it fills with water, secondly water will rust most of the componantry inside your engine.

Spark plug :- In the wet you can run a hotter plug than a normal plug for example a B9EG. This plug is very hard to foul up however only use in wet conditions as your engine will overheat with the plug in the dry.

Tuning :-You will have to run the jets on your engine leaner as you simple will not use the same amount of fuel in the wet because your engine will not run as hard. Bring the low speed in about a 1/4 of a turn and the high speed about an 1/8th is safe and should see your engine run stronger.

Water Repellant :-It is a good idea to spray the top of your plug cap and the top of your carby (be careful not to spray inside your carby) with water repellent such as RP7 or CRC.

Brakes :- Putting tape or a number plate across the chassis in front of brake system is a good idea. It will prevent dirt and grit getting into your braking system which could also cause your brakes to jam on.

Quick Chassis Setup Guide

In another article contributed by Century Performance Products, here is a quick-guide for the novice karter learning how to adjust his/her chassis. As ever, it is important to remember that technical articles represent the opinions of the author, and that these submissions are intended to be a starting point for the racer headed towards building his or her own knowledge base.

Dry Setup (Green Track)

The following settings are recommended as a starting point for a dry track with little grip. These types of tracks are often referred to as "green," given the inherent lack of grip in them. The attempt here is to gain more grip from the kart. The following recommendations should aid in this.

Weight Distribution should be 43.0% front, 57.0% rear, and 50/50% side/side.

Toe should be set out 1/16".

Camber should be set at -1/2 degree.

Castor should be neutral.

Front bumper should be tight.

Front width should be 44" to 44 1/2".

Nerf bars need to be tight.

Seat should be set according to factory recommendations.

Pinch bolts should be tightly secured.

Rear wheel hubs should be medium to long.

Rear ride height should be as high as possible.

Rear track should be set just below the legal limit, within the rules.

Axle type B should be installed (medium).

There should be at least two seat struts on each side of the seat.

Rear torsion bar should be in, positioned in either the flat or vertical location.

Rear bumper should be tight.

Dry Setup (High Grip Track)

The following settings are recommended as a starting point for a dry track with much grip, perhaps one that has a lot of rubber laid down.

Weight Distribution should be 43.0% front, 57.0% rear, and 50/50% side/side.

Toe should be set out 1/16".

Camber should be set at -1/2 degree to 0 degree.

Add positive castor past neutral.

Front bumper should be tight.

Front width should be 44" to 44 1/2".

Nerf bars need to be loose.

Seat should be lower than the factory recommends, as far as 1/2" below the frame rail.

Pinch bolts should be out.

Rear wheel hubs should be of the shortest length.

Rear ride height should be as low as possible.

Rear track should be set just below the legal limit, within the rules.

Axle Type A should be installed (soft).

Seat struts should be removed or loosened.

Rear torsion bar should be removed.

Rear bumper should be loose.

Rain Set-Up

Driving in the wet is extremely challenging, even more so if you are stuck with a dry set-up. Below are a few steps a driver can take before entering a drenched circuit, other than the obvious one of changing to rain tyres.

Move the front wheels out as far as possible. Some manufacturers have extensions that attach to the spindle, making it possible for the front track to increase even more.

Rear track should be moved in as far as possible; move the rear wheels in until the centerline of the rear tread aligns with the inside edge of the front tyres.

Add rain pills for maximum caster.

Increase camber if possible.

Toe should be set from 1/4" to 1/2" out.

Front bumper and nerf bars should be loose, rear bumper should be tight.

Increase tyre pressure: the front tyre pressures should be around 8 pounds, the rear tyre pressures should be around 20 pounds.

Remove any additional seat strut bolts from the seat side only.

Use only short rain hubs.

Use only aluminum wheels.

Loosen chassis pinch bolts.

Move the rear of the seat up around 1" to 1 1/4" above normal recommendation.

Rear ride height should be as high as possible.

Shield water from splashing on the brake rotor. Taping up the seat struts usually accomplishes this.

Tape closed each side pod, so as to prevent water from entering either one.

Use a hotter sparkplug.

Spray the ignition with a water repellent, such as WD40.

Article courtesy of Century Performance Products

Invader Chassis Setup Manual

For Sprint Setup

DISCLAIMER: This page is written and maintained by Galownia Motorsports Marketing LLC comments@galowniamotorsports.com and is not affiliated with Nelson Manufacturing.

Weight Distribution

Introduction to Weight Distribution

The most important handling adjustment is made before the kart reaches the track. The kart must be scaled and adjusted to ensure optimum performance. The desired weight distribution is achieved by scaling and adjusting the chassis to ensure optimum performance. Improper weight distribution can cause front end push (understeer), excessive oversteer, excessive or insufficient load on any one tire, chassis binding, and lack of side bite in cornering. Although other factors in setup mentioned in this manual (castor, seat placement, tire pressures, tire compounds, track, etc) can cause some of the above problems, an improper weight distribution can result in improper diagnosis of problems at the track when the problem is actually very basic. For sprint, racing the following is recommended:
40%-43% Front Weight
57%-60% Rear Weight
50%:50% Left/Right Weight
This is a good starting point. If you are racing on club tires such as Bridgestone YBN’s, you may want to setup the rear close to the 60% mark due to the low adhesion factor of these tires. If you run more on open tires, then more front end weight can be added to improve turn in. Side to side is critical to maintain as close to 50/50 as possible, as most sprint tracks have a variety of left and right turns.

Seat Placement/Adjustment

The seat placement is the single most important wieght adjustment on the kart and is usually done prior to actual weight distribution analysis. Therefore, a few general guidelines and rules are useful to know during seat mounting.

Adjusting the seat so that you sit high will cause dramatic weight transfer during cornering because of the large lever arm this position creates. This will cause the kart to lose grip during cornering. Laying low in the seat is just as bad but with the opposite effect; the kart will not track correctly due to excessive grip. Mounting the seat too far forward will not only disrupt the weight distribution, but make the kart uncomfortable. Mount is as left as needed to balance the weight of the motor.

Factors to Check Prior to Performing Weight Distribution Analysis

The following processes are all very important to ensuring accurate weight distribution analysis.

Ensure that the floor is level. This can be done by purchasing a 5-6 ft level and checking floor where the centerlines of the front and rear axles will rest. Also the floor should be checked across the width of the wheel base to ensure that it is not impacting the rake of the kart. An uneven floor can be compensated for by placing shims under the appropiate wheel(s).
Set toe and center the steering wheel. If the wheels are not centered during weighing, the geometry of the kart, mostly the castor, will cause the corners of the kart to be loaded incorrectly. The readings on your scales will then be false.
Set castor and camber.  
Set spindle heights at desired height.  
Tire pressures checked and at race settings  
Add weight in appropriate places to approximate fuel and/or oil. Remember, however, that fuel and oil weights are dynamic. They will change during a race.
Replicate racing conditions. When driver is in kart it is critical that they maintain a normal driving position as movements will effect readings. Wear race gear during weighing to have the highest level of accuracy possible.
Zero all scales.  
   
   


Adjusting Kart Weight

Kart weights are usually not at the desired specifications after the first weighing. If distribution is off, and weight is needed, begin to place the appropiate amounts in the appropiate places. By following the seat setup as described earlier, you should be able to achieve the 50/50 side to side distribution. Remember, seat placement is the single most important weight adjustment on the kart. With a Yamaha, you will be within a tenth or two on the side to side percentage. However, with a Briggs, the right side may be in the 50.7% range. This can be compensated for by adding weight to the left side. The amount will be dependent on how close you are to the limit for your class. If you have a light weight driver and need wt in the 10+ or more pound range, Invader makes weight cans which can be bolted to the back hoop below the driver's seat and moved either left or right as needed. These can be filled with lead shot and will weight around 12 lbs. If you do not need that much, mix the lead with sand or other diluent to achieve the desired weight. Remember that without any dilutent, the shot will move around during cornering and slightly upset the chassis.

Although overall side to side weight distribution may be correct, individual front or rear side to side distribution may be slightly skewed. If this is not the case, and there is a large difference across two wheels, recheck all of the factors effecting weight distribution given above and reweigh. If this still does not rectify the problem, you may have a chassis problem.

Once final placement is determined, secure all weight properly. Preference is Grade 5 or better 5/16 bolts of appropiate length. Be sure to cross drill and safety wire or safety clip each one. Most sanctioning bodies require double nutting of ballast as well. Be sure to check your rule book. Take the time to safely secure weight as this could cause critical problems for other drivers at the track if your weight comes loose . Not only does this have the potential to cause injury and equipment damage, it is basis for disqualification during a race.

Front End

Introduction to the Front End

Many important and easy handling adjustments can be made to the front end of the kart. Turn in, bite, and response can all be corrected by simple adjustments to the front of the kart.

Toe Adjustment

The toe settings on a chassis not only effect the weight distribution, but also top speed and cornering response. The more the kart is toed in or out, the slower the top speed becomes due to excessive drag by the tires when they do not point straight ahead. Increasing toe in will make cornering response faster, but only to a point. Toe out will make the kart feel touchy and awkward. Neutral position slows cornering response and reduces front end grip slightly. It is recommended to try 1/8"-1/16" toe in for an Invader chassis that do not use acrimen steering. For acrimen steering, a neutral toe setting is best.

IMPORTANT: When making adjustments to toe, make sure that the toe is equal on each side. Twist the tie rods until they are completely in or out, and mark them. Turn them back in from there, measuring toe and counting turns until the desired point is reached.

Castor

Castor effects the bite of the front and rear end and also changes apparent weight of the steering. It does this by transferring weight to the opposite rear wheel during cornering. The less castor in a kart, the less road-feel the driver will receive. Castor adds feel and bite to the front end. On Invader karts, there are three pills used to adjust the castor:
.110
.065
"neutral"
Each one of these has a hole drilled in it for reference. By alinging this hole either towards the front or rear of the kart, five different levels of castor can be achieved. See the following drawing:

For most applications, use the castor pill for the least amount of castor. Too much castor slows the cornering speed of the kart due to unnecessary grip. However, on cold days, or if conditions necessitate hard tires, adding castor can help prevent understeer and make the kart more driveable.

Spindle Height

By rearranging the six spindle spacers, the spindle height of each side of the kart may be changed. Generally, it is good to keep the heights even on both sides, but if the gap between the weights of the front tires is large, and the toe and castor are set correctly, the spacers may be adjusted to make up for this problem. However, before doing this, check to make sure that all tire pressures wer set properly during weighing.

Wheel Spacers

A quick adjustment to the handling of the front end kart is to change its track. For the effect of this to be most beneficial, the rear track must be set correctly and the differenc between the front and rear tracks should not be drastically skewed. However, the front should be narrower than the rear. The difference between tracks will vary between 4 and 2 cycle karts, but in general, a large skew where the front is much narrower than the rear will cause the kart to bind up in the corners and then hop. This is because the lever arms acting on the front of the kart and the rear will be very different, causing the front to flex much more than the rear and therefore bind up the chassis. Also, the front may be turning in much too fast for the rear of the chassis' flex rate to keep up. This will cause the kart to hop as the rear slides out and then grips.

For understeer, good practice is to narrow the front track. Another option is to widen the rear track, but it costs more time than the adjusting the front track. Start with the front track. If this doesn't do it, try either loosening the front bumper bolts or changing tire compounds to a lower durometer reading.

If the kart is oversteering, increasing the front track my help slightly, however, moving the rear track in is usually more effective. Another solution is to soften the chassis by adjusting the side bolts, seat struts, or torsion bar.

Rear End Adjustments

Introduction to the Rear End

The rear end of a kart begins from the back of the seat. The ajustments included in this range are: track, torsion bar, seat struts, side bolt tightness, bearing cassette height, third bearing addition/removle, and axle thickness. Learning to recognize the problems and benefits of these adjustments is critical to improving lap times.

Rear Track Adjustment

Rear track allows you to tune out oversteer and understeer by moving the wheels in or out. For oversteer it is best to make the rear track more narrow. A quarter inch per side is a good place to start. For understeer, widen the rear track by the same increment. However, sometimes, the kart may seem to be very tight (it may be hopping in the corners). Although this could mean the track needs to be widened, it can also mean the opposite. This is because when the track is too wide, the kart will slide out in the corner, bite and subsequently hop. Narrowing the rear track can oftentimes help this. This is usually not the case, however, when using club tires such as a Bridgestone YBN.

Side Bolts

Tightening the side bolts on the chassis is essentially equivalent to stiffening the chassis slightly. Loosening the side bolts will produce more grip on all four tires. This enhanced grip is most prominent in the rear, although this adjustment can be made to correct for slight powersliding. The bolts should be both tightenened or both loosened. Having one tight and one loose results in only slight handling changes.

Seat Struts

Seat struts are one of most tricky adjustments on an Invader kart and take some experience to understand. Adding seat struts causes the the outside rear tires in a corner to expereience increased downforce. From our experience, seat struts can reduce chassis hop during cornering. When the chassis is hopping in a corner, it means that the tires are gripping so well that they overflex the chassis. The kart then acts like spring to releive the flex, and the kart hops around the corner. Adding seat struts in this situation is a last resort, when no other adjustment will tune out the hop. The increased downforce on the tires from the seat struts results in a force that exceeds the force of friction generated by the tires, so that they will slide around the corner.

Adding seat struts when the kart is loose can increase grip, but it is more likely that an Invader kart will be tight than loose.

Rear Torsion Bar

Adding a rear torsion stiffens the rear of the kart dramatically, disallowing chassis flex. Adding this torsion bar can therefore be used to induce oversteer. The torsion bar can be mounted so that the flat spot is vertical or horizontal, but the vertical setting creates a stiffer chassis, and therefore greater oversteer.

It should be noted, however, that with sufficiently soft tires, adding a torsion bar to induce oversteer can induce hopping in the chassis. To understand how this occurs, realizae that as a chassis flexes during cornering, it stores energy, much like a spring does when it is pulled or contracted. This energy gives rise to a restoring force in the chassis, and when this force exceeds the gripping force of the tires, the tires will suddenly lose grip, and the chassis will "hop." The force on the chassis is then relieved, and the process starts over again. In general, hopping becomes more severe with softer tires, becuase softer tires provide a larger grip force, allowing a larger amount of energy to accumulate in the chassis during cornering.

As the chassis becomes stiffer, (as it does when the torsion bar is added) it becomes a stronger spring. This means that for a given tire compound, increasing the stiffness increases the chance for hop. As with all chassis adjustments, there is a balance between tire compound, chassis stiffness, and hopping, which must be found for optimal performance.

TonyKart Chassis Setup Manual

For American Sprint Setup

DISCLAIMER: This page is written and maintained by Galownia Motorsports Marketing LLC comments@galowniamotorsports.com and is not affiliated with Tony Kart.

Weight Distribution

Introduction

The most important handling adjustment is made before the kart reaches the track. The kart must be scaled and adjusted to ensure optimum performance. The desired wieght distribution is achieved by scaling and adjusting the chassis and moving around weights. Improper weight distribution can cause front end push (understeer), excessive or insufficient load on any one tire, chassis binding, and lack of side bite in cornering among many other problems. An improper weight distribution can also lead to incorrect diagnosis of handling problems at the track. For Tonykarts, the following weight distributions are recommended:
43% Front Weight
57% Rear Weight
50%:50% Left/Right Weight
These are just recommended starting points. Weight can be moved around at the track to change the handling characteristics of the chassis. Moving weight to the front of the kart will provide more front end grip while moving weight to the rear of the kart will provide more rear grip. Weight can also be moved vertically up or down. Moving the weight vertically upwards will provide more grip in the location of the weight while lowering the vertical position of the weight will have the opposite effect. Keep the side to side weight distribution as close to 50%:50% as possible.

Seat Placement/Adjustment

The seat placement is the single most important weight adjustment on the kart and is done before weight distribution analysis. Perfect seat placement may result in almost perfect weight distribution before any weight is even added to the kart. Tonykart provides a set of specifications for seat placement that should be followed as closely as possible. Consult your local Tonykart Dealer for specifications for your specific model.

Factors to Check Prior to Performing Weight Distribution Analysis

The following processes are all very important to ensuring accurate weight distribution analysis.

1. Ensure that the floor is level.
This can be done by purchasing a 5-6 ft. level and checking the floor where the centerlines of the front and rear axles will rest. The floor should also be checked along both sides of the kart across the width of the wheel base. Compensate for an unlevel floor by placing shims under the appropriate corner scales.
2. Set toe and center the steering wheel.
If the wheels are not centered during weighing, the geometry of the kart, mostly the castor, will cause the corners of the kart to be loaded incorrectly. The readings on your scales will then be false
3. Set castor and camber
4. Set spindle heights at desired height.
5. Check tires to make sure they are at race settings.
6. Add weight in appropriate places to approximate fuel and/or oil.
Remember, however, that fuel and oil weights are dynamic. They will change during a race.
7. Replicate racing conditions.
When the driver is in the kart, it's critical they maintain a normal driving position as movements will effect readings. Wear full race gear during weighing to have the highest level of accuracy possible.
8. Zero all scales.

Adjusting Kart Weight

Kart weights are usually not at the desired specifications after the first weighing. If distribution is off, and weight is needed, begin to place the appropriate amounts in the appropriate places. By following Tonykart's seat specifications, you should be able to obtain 50/50% side to side distribution. If you are way off on your side to side weight distribution than recheck your factors effecting weight distribution. You might have to move the seat just a little bit to obtain the correct weight distribution. If you are at the limit of your specific weight class than you might have to live with weight distribution that is not perfect. However, your Tonykart seat specifications should put your distribution pretty close. If you are under your specific class weight limit, add weight to the appropriate locations. Do not place any lead shot inside the frame. The weight will shift during cornering and cause handling problems.

Although overall side to side weight distribution may be correct, individual front or rear side to side distribution may be sligthly skewed. Your front wheels should weigh within 5 lbs. of each other while the same applies to the rear wheels. If this is not the case, recheck all of the factors effecting weight distribution given above and reweigh. If the problem still exists, you may have a chassis problem.

Once final weight placement is determined, secure all weight properly. Preference is Grade 5 or better with 5/16 bolts of appropriate length. Be sure to cross drill and safety wire or safety clip each one. Most sanctioning bodies require double nutting of ballast as well. Be sure to consult your rule book. If your weight is not secure, this can cause serious problems for other drivers at the track if your weight comes loose. Not only does this have the potential to cause injury and equipment damage, it is basis for disqualification during a race.

Front End

Introduction to the Front End

Many important and easy handling adjustments can be made to the front end of the kart. Most handling problems that occur during the entrance of the corner are probably results of improper front end adjustment. Turn in, front end bite, and steering response can all be corrected by simple adjustments to the front of the kart.

Toe Adjustment

The toe settings on a kart can effect weight distribution, top speed, and cornering response. The more the kart is toed in or out, the slower the top speed becomes due to excessive drag by the tires. Increasing toe out will increase initial cornering response. If the kart feels touchy and the back end gets loose at the entrance of the corner than you probably have too much toe out. Neutral toe adjustment is recommended for Tonykart chassis. The toe should only be changed as a last resort. Look to other adjustments first to correct handling problems before changing your toe settings.

IMPORTANT: When making adjustment to toe, make sure that the toe is equal on each side. Twist the tie rods until they are completely in or out, and mark them. Turn them back in from there, measuring toe and counting turns until the desired point is reached.

Castor

Castor effects the bite of the front and rear end and also changes apparent weight of the steering. It does this by transferring wieght to the opposite rear wheel during cornering. The less castor in a kart, the less road-fell the driver will receive. Castor adds feel and bite to the front end. On Tonykarts, there are two pills used to adjust the castor giving you three possibilities:
12 degrees
Neutral (14 degrees)
16 degrees
For most applications, use the neutral castor pill. Too much castor slows the cornering speed of the kart due to unneccessary grip. However, on cold days, or when the use of harder compound tires are required, adding castor can help prevent understeer and make the kart more driveable. Although the use of 12 degrees castor in Tonykarts is uncommon, it may be necessary under sticky track conditions to free up the kart.

Spindle Height

By rearranging the two spindle spacers, the spindle height of each side of the kart may be changed. Keep both sides the same height. By moving both spindle spacers to the top of the spindle, you are raising the front end of the chassis. Raising the chassis height creates more leverage in which to transfer side weight to the opposing tire and thus results in more front end bite at the entrance of the corner. Lowering the chassis, or moving both spindle spacers to the bottom of the spindle, has the opposite effect and creates less front end bite at the entrance of the corner.

Wheel Spacers

The most common and easiest adjustment to make to the front end of the kart is to change the front track, or front end width. Widening the front track will create more flex in the front end of the kart and result in more front end grip and quicker turn in. Narrowing the front track will have the opposite effect and result in slower turn in and less front end bite.

Camber

Rear End Adjustment

Introduction to the Rear End

The rear end of a kart begins from the back of the seat with adjustments including wheel hub length, track, rear ride height, axle stiffness, and seat struts. Changes to these settings are usually made when handling problems occur on the exit of the corner.

Wheel Hub Length

Tonykart makes three different wheel hub lengths for their chassis. It's highly recommended that you purchase all three of these sizes as they are the most commonly adjusted setting on the kart. The longer the hub the more rear end bite. Use the shortest hub if the kart feels tight at the exit of the corner and use the longest hub when the kart feels loose at the exit of the corner.

Rear Track

For American sprint racing, most rules dictate a maximum rear track of 50.0 inches. Because Tonykarts are raced primarily in Europe, they are designed for rules allowing a 55.0 inch rear track. Therefore, it is important to set your kart's rear track to the maximum of 50.0 inches. It becomes necessary to narrow the track when the rear of the kart is tight at the exit of the corner and has too much rear end bite. However, this is an adjustment only made when you have first changed your wheel hub length to the shortest hub available and are still tight at the exit of the corner. Narrow the rear track in 1/2 inch increments.

Rear Ride Height

On most Tonykart chassis there are two setting for the rear ride height. The factory recommends running the chassis with a higher ride height for better grip. The higher ride height, like the front end, creates more leverage in which to transfer the cornering loads to the opposing tire and thus results in more grip. Lowering the rear ride height will have the opposite effect and cause the kart to be extremely loose. Only in extreme cases should you change the rear ride height.

Axle Stiffness

Tonykart makes two types of axles for American Sprint Racing, type N and type C with the type N being the softer axle. In almost all cases you will use the type N axle. Such cases in which you may need to use the type C axle are cold weather, slippery track conditions, and when rules mandate the use of harder compound tires. You shouldn't' be afraid to run a type C axle but at the same time, changing to the type C axle is a dramatic change and should be used only when the rear end of the kart is uncontrollably loose at the exit of the corner.

Seat Struts

On a Tonykart chassis, the factory recommends running two seat struts on both sides of the seat running from the very top of the seat to the two outer bearing cassetes. On the motor side it may only be possible to use one strut. The seat struts allow the high leverage point of the driver to be used to transfer load to the rear tires and thus create more rear end bite. When the extra seat struts are removed, the drivers high position on the kart is not taken advantage of and minimal load is transferred to the rear tires. As a result, the kart becomes extremely loose. The seat struts are therefore only removed when all else fails to loosen up the rear of the kart. If you do have to remove seat struts, try removing one set at a time.

Miscellaneous Adjustments

Center Torsion Bar

Some Tonykart chassis have an adjustable torsion bar in the middle of the kart just below the seat. The bar can either be layed flat like a table top or vertical like a wall. Laying the bar flat will free the kart to slide from side to side while setting the bar vertical will give the kart more side bite and result in less drifting of the kart with all four wheels. Tonykart also makes different stiffness torsion bars to further enhance adjustment ability. The softer the bar the less side bite you will have.

Tire Pressures

Tire pressures can range dramatically from as low as 10 psi to 30psi depending on the compound of the tire. For extremely sticky tires you should stay between 10psi and 14psi. For SL tires like a Bridgestone YGC you can go as high as 16psi and with Dunlop SL4's you can go as high as 18psi. For extremely hard tires such as Bridgestone YBN's you will need to run tire pressures as high as 30psi. All tires have a range in which they work the best. In general, the higher the tire pressure, the faster the tires will come up to race performance and the more grip you will have. However, if you put too much air pressure in the tires, the kart will become very loose. The reason for this is because the high pressures will cause the tire contact patch to form a curve in which there becomes a high point on the center of the contact patch. As a result, only part of the tire is actually touching the track and the kart gets loose.

Front Bumper

Tonykart recommends keeping the front bumper tight at almost all times. However, loosening the front bumper can be used as a tuning tool. Loosening the front bumper will give you more front end bite.

Side Pods

In normal circumstances you will want to leave the side pods tight although you shouldn't' be afraid to loosen them as a chassis adjustment. Loosening the side pods will give the kart more side bite and allow for less four wheel sliding.

Troubleshooting

Below is a chart of quick and easy adjustments recommended for different handling problems. Always make only one adjustment at a time.

Handling Problem Chasis Adjustment

The back end is loose at the entrance of the corner or there is too much front end bite.
1. Move in one wheel spacer on both spindles
2. Drop 1 psi in the front tires
3. Move weight away from the front of the kart
4. lower the front of the chassis
5. Put less castor in.
6. Tighten the front bumper if not already tight.
7. Check to make sure your toe is set at neutral

The front end of the kart is "pushing out", there is understeer, or the back end is tight at the entrance of the corner.
1. Move out one wheel spacer on both spindles.
2. Raise the air pressure in the front tires by 1 psi.
3. Add weight to the front of the kart
4. Add more castor.
5. Raise the front end of the kart
6. Loosen the front bumper.
7. Check to make sure your toe is set at neutral, add more toe out.

The kart is sliding on all four wheels too much or there is not enough side bite.
1. Turn the torsion bar in the center of the kart to the vertical position.
2. Loosen the side pods.
3. Raise the air pressure in all 4 tires by 1 psi.

The kart is not sliding enough on all four wheels or there is too much side bite.
1. Turn the torsion bar in the center of the kart to the horizontal position.
2. Tighten the side pods.
3. Lower the air pressure in all 4 tires by 1 psi.

The kart is loose at the exit of the corner.
1. Put longer wheel hubs on the axle.
2. Set the rear track to the maximum 50.0 inches if not already done.
3. Raise the air pressure in the rear tires by 1 psi.
4. Raise any ballast to a higher vertical position on the rear of the kart.
5. Raise the rear ride height to the maximum if not already done.
6. Change the axle to Type C.

The kart is tight at the exit of the corner or the front end is understeering at the exit of the corner.
1. Put shorter wheel hubs on the axle.
2. Move in the rear track by 1/2 inch.
3. Lower the air pressure in the rear tires by 1 psi.
4. Change the axle to Type N if not already done.
5. Lower any ballast to a lower vertical position at the rear of the kart.
6. Remove one set of seat struts.
7. Lower the rear ride height.

Dry Setup

The following settings are recommended only as a starting point for dry race setup.

Weight Distribution 43.0% Front, 50/50% side/side
Toe Neutral
Camber Neutral
Castor Neutral
Front Bumper Tight
Spindle Height Neutral
Wheel Spacers Three spacers on the inside (Tonykart wheels)
Center Torsion Bar Horizontal
Side Pods Tight
Rear Wheel Hubs Medium Length
Rear Ride Height Heigh
Rear Track 50.0 inches
Axle Type N
Seat Struts At least 3 in place

Rain Setup

Whenever it rains, there is a lot more you can do to your kart other than just changing to rain tires. The following changes are recommended.

Castor > Full Castor Pills
Front Bumper Loose
Front Ride Height > High
Wheel Spacers > Move front wheels out as far as possible
Center Torsion Bar > Vertical
Side Pods > Loose
Rear Wheel Hubs >Shortest Hubs
Rear Ride Height >High
Rear Track >Move in wheels as far as possible

How Fast Do Karts STOP!!

As a useful database for the track inspector's manual it became important to know the stopping distance of karts as an input to the fence and barrier setback distances and give some science to the art of bark chip and gravel pit design. I was not able to find any published data and best guesses from experienced drivers and technicians varied by a factor of 2. It was decided to physically measure the best under the best conditions and this would be the benchmark for every other kart.

TECHNICAL PREAMBLE: - Sprint kart breaking is a challenge. The rear wheels are braked usually by a large disc with hydraulic callipers but some mechanical callipers are still available and used. As deceleration occurs the rotational movement puts weight on the unbraked front wheels and tends to lift the rear wheels. On the positive side, kart weights are low, e.g. For Formula A approximately 142kgs and the braked tyre contact footprint varies from approximately 170 square centimetres to 180 square centimetres depending on tyre pressure and the amount of wear to the tyre.

THE TEST: The opportunity to accurately test braking distances occurred on Tuesday the 26TH January, 1999 whilst practice was being carried out for the 1999 Oceania on very good quality hot mix at Eastern Creek International Kart Racing circuit. The ambient air temperature was 30 degrees Celsius. We had sole access to the circuit during the test so distance could be physically checked with a tape measure. The karts were fitted with the latest accurate data loggers.

TEST NO.1: Involved Brendan Dive driving a Birel equipped for Formula A on near new Dunlop RM8 tyres. Stopping from 100 kilometres per hour on three sequential test laps. Later downloading checks of the data logger confirmed distances and speeds. The best distance Brendan achieved from 100km/hr was 31.7 metres. The second best was only 15 cms longer. It was interesting to note that during one run a brief high-speed lock up increased the braking distance by almost four metres.

TEST NO.2: Involved down loading the Data Logger details from Michael Caruso Tony Kart equipped for Formula A on Bridgestone RS tyres. The best deceleration was from 100 km/hr to 51.9 was 20.8 metres.

CONCLUSION: Formula A karts on high quality hot mix with elite drivers and soft open compound tyres stop in about the same distance as published figures for High Performance road cars
EG Subaru WRX 100km/h to zero 31.5 metres
Porsche 911 S4 100km/h to zero 32.0 metres
Ferrari F40 100km/h to zero 32.1 metres
NB 1995 Williams Formula One 100km/h in 16.1 metres.

I look forward to testing a 125cc Gear box kart equipped with four wheel braking in the near future. It stands to reason that a lessor skilled karter, on harder compound tyres, would take longer to stop than a Formula A outfit.

Many thanks to the Eastern Creek International Karting Raceway, Steve Ellis the Track Manager and Garry Holt and both the Birel and Tony Kart Race Teams for the privileged access during very busy times.

KART SETUP By 15 Times Australian Champion, John Pizarro

Wet Weather

In this issue I would like to go into some detail about what to do in wet weather conditions and how to set your kart up for the best results.

The very first and most important thing is to have a positive attitude about the conditions. It might be cold and wet but remember it’s just as cold and wet for the other guy too. Let him feel miserable and tell everyone how silly you are, being out in the rain. You tell yourself and the other drivers how good it is and how it helps to improve your kart control (and it does) and any other positive points that you can think of. You will then have the psychological advantage over the other drivers.

If you think you can win you are halfway there.

Now to the kart - As most classes use slick tyres in the wet or dry, I will talk first about setting up on slicks, not that there is much difference in the setup if you use slicks or rain tyres.

Loosen the kart up all round, front bumper, rear bumper, side pod bars and any other component that is likely to stiffen the chassis. Set the front track as wide as possible and the rear track in 10mm per side from the standard setting. It is important to try to maintain good balance front and rear. If you set the rear track too narrow you may generate too much rear end grip which will result in severe understeer (no grip on the front). Generally speaking, you won’t suffer from too much front end grip in the rain no matter how wide you set the front track.

PAdjust the toe out up to 15mm, this will help the kart to turn into the corners and also help to generate some heat in the front tyres.

Tyres are the next consideration. Narrower wheels can be an advantage as they allow the tyre wall to flex. Front wheels at 100mm wide and rears at 175mm will give good results. Tyre pressure should be set at about 3.0kPa (45lb) font and rear. What we are trying to do is get some heat into the tyres, so by using narrow wheels and high tyre pressure the tyres will be larger in the centre than they are on each side of the contact area. This means a narrow strip of rubber on each tyre is in contact with the track. We have some chance of getting heat into a narrow strip of rubber and consequently some grip, but no chance of heating the whole tyre.

Gear ratio should be changed for two reasons. One, because the diameter of the rear tyre has been increased, and two because the length of the straights on track have been reduced. How is that so you say? Well because the track is so slippery, you come onto the straight at a slower speed and you get off the power much earlier at the end of the straight. Increase the axle sprocket by 3-4 teeth for most tracks.

Wheel spin out of corners can be a problem in the wet and some will say that we have just gone the wrong way with gear ratio for this reason. Don’t believe them. This is where the driver comes in. You must be very smooth and if need be, drag the brake a little at initial acceleration. It’s also a good idea to locate the throttle cable on the lowest pedal setting. This means more pedal travel to open the throttle. I set the throttle cables on my twin in this manner as wheel spin is a real problem in the wet or dry with the power it produces.

Raising the seat will improve your lap times as the weight transfer in corners will be greater due to the higher centre of gravity (you never see a kart two wheel in the wet). Lift the seat as much as 100mm and be sure the seat is not tight, as this will stiffen the chassis. If your kart has ride height adjustment, raise the chassis to its highest setting.

Be sure to fit a guard on the air box to prevent water getting into the engine. You can buy a ready made guard that will do a very good job, or if you get caught out, an old oil bottle with the end cut out and facing back will do the job.

A small amount of water inside your engine can wear it out in one race meeting, so take care with your air box guard.

A shield in front of the brake calliper is also a good idea. Lubricate tie rod ends and all bearings and spray the axle and all metal components to protect against rust. Good wet weather clothing is an obvious advantage and a turbo visor can be a huge benefit. The turbo visor simply fits on the front of your helmet and spins as you race, giving clear vision. You can purchase a turbo visor from most kart shops.

If you race on rain tyres there are a couple of things to keep in mind. First of all, be sure the track is really wet as you can destroy a set of rain tyres on a drying track in a few laps.

Tyre pressure is usually set at close to dry tyre pressure, between 1 and 1.4kPa(15 to 20lb). Be sure to fit the tyres with the correct direction of rotation.

Next time we will have a look at setting up in dry conditions.

Dry Set-up By 15 Times Australian Champion – John Pizarro

Last issue we went into some detail about setting the kart up for wet conditions. This time I would like to talk about setting up for dry conditions. I think I am probably doing this back to front but never mind, we will get there at the end of the day.

First of all refer to your Owner’s Manual and adjust your kart to the manufacturer’s recommended settings. If you don’t have an Owner’s Manual ask your kart supplier for his recommendations.

I will now go through the various components on your kart and explain how you can alter its handling by making adjustments to them.

Front Bumper: The front bumper also acts as a torsion bar on the front axle. If the bumper is fitted with no tension on the mounting bolts, the front axle can flex a little easier and in some conditions will give better front end grip. Tightening the front bumper mounting bolts will stiffen the front axle. This will reduce bounce caused by rough track surface or excessive grip.Front Bumper: The front bumper also acts as a torsion bar on the front axle. If the bumper is fitted with no tension on the mounting bolts, the front axle can flex a little easier and in some conditions will give better front end grip. Tightening the front bumper mounting bolts will stiffen the front axle. This will reduce bounce caused by rough track surface or excessive grip.

Rear Bumper: Loose tension on the rear bumper adjustment will achieve maximum rear end grip but may cause rear end bounce if the track offers good grip. It may also induce understeer (lack of grip on the front end when turning). If the rear bumper is too tight for the track conditions you will lose rear end grip. Rear Bumper: Loose tension on the rear bumper adjustment will achieve maximum rear end grip but may cause rear end bounce if the track offers good grip. It may also induce understeer (lack of grip on the front end when turning). If the rear bumper is too tight for the track conditions you will lose rear end grip.

Side Pod Mounting Bars: These also act as torsion bars. Tightening the side pod bars will stiffen the chassis. This may be beneficial when the track offers good grip.Side Pod Mounting Bars: These also act as torsion bars. Tightening the side pod bars will stiffen the chassis. This may be beneficial when the track offers good grip.

Toe In: In a previous article we went into some detail about the correct method of setting up the steering assembly. I think it is sufficient to say the preferred setting for toe is zero. That is, both wheels straight ahead. Setting the wheels with a small amount of toe out (3-4mm) will help the kart turn into a corner but I don’t think it will do it any good down the straight.

Front Track: Front and rear track settings are most important in getting the best out of your kart so take care in this area. When making adjustments to the front track move each wheel a maximum of 5mm per adjustment. Moving the wheels out will increase front-end grip. If you make the front end too wide for the circuit conditions the kart will "oversteer". That is, turn into the corner too quickly. It may also become unstable on change of direction and will be heavy to steer. I like to set the front track as narrow as I can, but of course wide enough to maintain good grip when turning. Running a narrow front track will also help tyre wear and temperature. A wide setting means a greater scrub rate (distance from the kingpin to tyre), more friction on the tyre and hence more heat and wear.Front Track: Front and rear track settings are most important in getting the best out of your kart so take care in this area. When making adjustments to the front track move each wheel a maximum of 5mm per adjustment. Moving the wheels out will increase front-end grip. If you make the front end too wide for the circuit conditions the kart will "oversteer". That is, turn into the corner too quickly. It may also become unstable on change of direction and will be heavy to steer. I like to set the front track as narrow as I can, but of course wide enough to maintain good grip when turning. Running a narrow front track will also help tyre wear and temperature. A wide setting means a greater scrub rate (distance from the kingpin to tyre), more friction on the tyre and hence more heat and wear.

Seat Position: As the driver generally weighs more than the whole kart you can see that it is important that the seat is in the right position. If you move the seat from the manufacturer’s recommended position 20mm should be the limit per adjustment. If you move the seat forward you will increase front-end grip. If you move the seat backward you will increase rear end grip and reduce front-end grip. If you raise the seat you will increase front and rear grip but if you go too high the kart will become unstable. If you lower the seat you will reduce front and rear grip. The final seat position will depend on the size and weight of the driver and the track condition. A light weight or short driver will need to have the seat higher to achieve the same centre of gravity as a tall driver. Also, on tracks that offer poor grip you could position the seat higher that you would for a track that has good grip.

Ballast Weight: Any weights should be bolted to the seat to supplement the driver’s physique. Light weight drivers may need the ballast positioned higher on the seat in order to achieve the same

centre of gravity as an average weight driver. I often see ballast weight bolted near the front axle to help steering. It is much better to move the seat forward because if you lose control the kart will be more inclined to spin if the weight is right up the front rather than in the middle.

Rear Track: Start with the wheel hubs in the recommended position. Move each wheel 5mm per adjustment. The response to rear track adjustment will vary depending on the track and weather conditions. Where the track offers low, medium or good grip the response will be as follows:Rear Track: Start with the wheel hubs in the recommended position. Move each wheel 5mm per adjustment. The response to rear track adjustment will vary depending on the track and weather conditions. Where the track offers low, medium or good grip the response will be as follows:

Narrowing the rear track will increase rear end grip. If the rear track is too narrow the kart may bounce and be difficult to drive and may even lose rear end grip. Too much rear end grip can also cause the kart to understeer. Widening the rear track will produce a smoother ride and make the kart sit flat in corners. If you make the rear end too wide, the kart will start to lose rear end grip. The best results will be achieved with a reasonably wide rear track set where you still maintain good grip.

In conditions where the track offers high grip, the wider you make the rear track the more grip the rear tyres will generate. Under these circumstances set the rear track in the position you would use on a track with good grip and adjust the rest of the kart around this setting.

Ride Height: Raising the ride height front and rear will result in an increase of grip. If the racetrack has good grip, use a low setting on the kart. If the kart is too high for the track conditions it will be unstable in fast corners.Ride Height: Raising the ride height front and rear will result in an increase of grip. If the racetrack has good grip, use a low setting on the kart. If the kart is too high for the track conditions it will be unstable in fast corners..

I could ramble on for quite a while on this subject but I think I have said enough for now..

Reading the Track By 15 Times Australian Champion – JOHN PIZARRO

Hero to zero, know the feeling? Me too. How many times have things looked so good only to end up so bad? I though I might just relate an experience I had recently to you to demonstrate how easily things can go wrong in the game we play called karting. The small team I am involved with, which consists of Tony ( he pays to work ). Nick ( he drives) and me ( I talk ) headed of to Raleigh Raceway on the north coast of New South Wales for a round off the CIK Series. We were running in the Intercontinental A Class (Reed Class) and had been running in the front half the field, in fact we gave them a great fight by winning a final at the Tamworth round. The eight-hour trip to Raleigh gave us plenty of time to discuss all sorts of things, like politics, how to set the kart up and how to win the race. Politics is not really a subject for discussion in this article, let me just say that some of the solutions we discussed were very popular in the 18th Century. How to set the kart up covered all sorts of things, remember we are running in reed class, big horsepower compared to Yamaha J or S with open compound tyres,much softer than SL tyres you use in National and Clubman Class, but the principles are much the same. The rear track is set at 1395mm. Maximum allowed next year is 1400mm. SL tyres perform well around the 1300mm mark. Remember rear track adjustments of 10mm each time is a good policy. Front track had been set a little wider than we had used at Tamworth and this would contribute to our downfall in due course. If it goes wrong with the front tyre of SL compound, multiply by factor of 10 and you have an open compound tyre. The wider you set the front track the more heat it generates and the greater the weight exerted on the tyre when turning. This is due to the angles within the steering geometry. You may also improve front-end grip with a wide setting. The best setting in mind is as narrow as practical, but still maintaining reasonable grip. Where we really came unstuck was with the camber setting. Too much negative camber also generates heat on the inside of the tyre, and that was us. I think a good setting for SL or open tyres is o" camber, that is to stand the wheel straight up. This is easy to check with a square on a level floor. The rest of the kart set up was pretty normal. Knowing the track from earlier in the year, we had the kart fairly stiff with the bumpers and sidebars (also torsion bars) tight. Ride height was set about the middle of the adjustment and we used the two pick-up points on the pitman arm to be sure the kart turned into the corners quickly. Next time I would like to test the single pick-up point on the pitman arm. If there is enough grip on the track, I think it would be easier on the front tyres. One of my pet hobbyhorses is gear ratio. Without a doubt a kart will go faster down the straight with a ratio at say 10 x 84 than it will with 10 x 86. The only problem is getting around the corners, and this is where the kart and the driver come in. Well you guessed it, last time we raced at Raleigh we used 10 x 86. The theory being that the driver would have to lift his level of skill and if the kart was good enough, he would be fast. Well it worked – almost! The kart was very good off the corners and Nick was driving at his best. The three engines we had with us were also going well. Two were off my twin, whilst the other was Nick’s own engine. My engines were about one tenth slower than Nick’s, so the plan was to qualify with Nick’s engine and run the heats with mine. That way his engine would be fresh for the finals. All three engines were running up to 17,900 – 18,000 rpm. On Sunday as the rubber went down and the track gained more grip, the best engine ran up to 18,200 rpm. That was a result of faster corner speed as the grip improved, which in turn gave us better top end speed. We qualified a very close second and won both the heats on Saturday, but at a high price. The front-end setting we used was wrong and the front tyres wore badly in the first heat. It was all hands on deck to fix the problem before the next heat, but the damage had been done. Camber back to zero, front track in to where we should have set it and the kart went like a rocket for the second heat. The next day we paid the price for having self – inflicted excessive wear and overheated front tyres. Fourth place a DNF and seventh from the back of the field was our lot - but look out at the next meeting. The problems we experienced with our open compound tyres are far more dramatic than you will strike with SL tyres, but the same principles apply. After a result like that you can imagine what a fun trip it was on the way home. Eight-hour seemed like twelve, no fifteen! It wasn’t that bad really, but you do have plenty of time for post- mortems ( and for Nick to sleep ). So what have you concluded from that lot? Perhaps it would be to do as I say and not as I do.

Steering Alignment By John Pizarro

First of all you need to position the pitman arm (that's the one that both tie rods bolt to) in the centre of the steering shaft. To do this first, measure from one king pin to the steering shaft at pitman arm level and then from the other king pin to the steering shaft again at the pitman arm level. Usually there will be a difference of 5 or 6mm in these measurements as the steering shaft in most karts is offset in line with the driver. Now measure from king pin to pitman arm and adjust same to reflect the variation in the steering shaft measurement ie. If the king pin to steering shaft measurement is 5mm longer on the right hands side the king pin to pitman arm measurement will be 5mm longer on the right hand side. Now clamp the bush at the top of the steering shaft with a pair of vice grips to hold the shaft in place.

By adjusting the length of each tie rod you can set the front wheels in their correct position. This is best done by removing the front wheels and fitting line up plates in the horizontal position. If these are not available put some tape on the front wheels as a marker and turn them from front to back so you can measure from the same spot on the wheel.

At the same time check that the front wheels are in line with the chassis. This can be done by placing a straight edge against the front wheel or line up plate and noting where it contacts the rear axle.

Do the same on the other side and then adjust the tie rods so that the straight edge against the front wheel or line up plate and noting where it contacts the rear axle.

Do the same on the other side and then adjust the tie rods so that the straight edge contacts the rear axle in the same position on both sides, whilst at the same time maintain the correct toe in or toe out.

Now a few words of explanation about toe in and toe out. Toe in is the term used when the front wheels point in at the front rather than being parallel and toe out is when the front wheels point out.

I never set a kart up with toe in. Normally I set up with zero toe in 2-3mm of toe out is okay if you want the kart to turn into the corners a little bit better, but remember there will be some drag in a straight line. On slick tyres in the rain up to 15mm toe out is okay. I think that's enough on front end set up for now, next issue we will talk about front end set up for now, next issue we will talk about front and rear track positions and how it affects the handling of your kart.

Chassis Adjustments By 15 times Australian Champion - John Pizarro

Last issue we went into some detail on how best to set up the front end alignment on your kart. Having the steering alignment adjusted correctly is most important to ensure that we get the correct result from the various chassis adjustments we may need to make.

In this issue I would like to talk about the effect that front and rear track adjustments make to the handling of the kart.

Starting always with the manufacturer's recommended settings and remember also that we are dealing here with karts in the SL tyre classes. Moving the front wheels out will help to get more grip at the front of the kart.

The trade off is that moving the front wheels out on the stub axle increases the scrub rate of the front tyre, causing it to wear faster and heat up to a higher temperature much more quickly. If you have the front track too wide it also tends to make the kart a little nervous or unstable when turning.

I like to set the front end of my kart a little towards the narrow side but of course you need to position the wheels so you get enough grip to turn the corner.

The rear track setting is important in getting the kart to handle the way you want and also effects the amount of power used to turn a corner. The best way to illustrate the amount of power used to turn the kart is, next time you have the engine off your kart, push it along the road. You will see how "easy" it goes in a straight line. Now turn the steering wheel, you will get a real surprise to see how much energy is needed to turn the kart.

So where do I set that rear track for the best result?

The exception to this is where there is excessive grip on the track after a lot of rubber has been put down in competition. Under these circumstances it is best to stick to the manufacturer's recommended settings as a wide rear track in these conditions will create too much grip. Any adjustment, front or rear, should be a maximum of 5mm per wheel.

As a wider rear track unloads the inside rear wheel more than a narrow rear track with the same amount of weight transfer, less energy is needed to turn with a wider rear track. This leaves a greater amount of power to propel the kart forwards faster

If you set the rear track too narrow, as well as using more power to turn, the kart may want to bounce in the corners. If you set the rear track too wide, under normal track conditions, the kart will tend to slide at the rear end. I like to set my kart up a little to the wide side but without losing grip on the rear end. I find this is the fastest setup.

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