Chapter 4: Miscellaneous Adjustments - j3 competition kosmic Manual

3.1: 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.
3.2: 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.
3.3: 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.
3.4: 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.
3.5: 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.
3.6: 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.

Chapter 4: Miscellaneous Adjustments

4.1: 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.
4.2: 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,
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