Troubleshooting guide

Kart Scaling & Weight Distribution

Weight distribution on a kart has a huge influence on the final performance of the kart on the track. The

mass of the driver is often greater than the kart itself, so this mass must be positioned properly.

Scaling the kart is perhaps the most important thing a driver or team can do to ensure proper handling

of their machine.

When the kart is scaled properly, ideal weight distribution is achieved. Therefore, the kart will have the

potential to perform at its optimum level. If the kart is not scaled properly, the opposite will be true. The

machine will never perform at its optimum level, nor will it respond positively to chassis adjustments. In

other words, if you make changes and the kart doesn’t seem to respond, then the seat is in the wrong

position and the kart isn’t scaled correctly.

Some problems of an improperly scaled kart include 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 most

karts, the following weight distribution is recommended as a starting point:

43% Front weight

57% Rear weight

50/50 Left/right weight

Any lead that might be added should be added as low as possible unless your primary track(s) are very

low grip (green). The four seat bolts should be very tight with no movement. The torsion bars should

be disconnected when scaling the kart. For most chassis, the seat bottom should be about 2cm (3/4”)

below the bottom of the frame. A tall driver can go as little as ¾” ground clearance from the seat

bottom. Tall drivers should also consider using a more flexible seat to help reduce chassis stiffness.

These are just recommended starting points. Weight can be moved around at the track to fine tune the

handling characteristics of the chassis. Moving weight to the front of the kart will provide more front

end grip. However, please be careful to not add too much front end weight, as it can make the kart

prone to larger understeer and oversteer swings when at the traction limit. If weight is moved to the

rear of the kart, the effect will be more rear end grip. Weight can also be moved vertically up or down.

Moving the ballast weight upwards will provide more grip (weight transfer).

Seat Placement & Adjustment

The seat placement is the single most important weight adjustment on the kart and is done before the

scaling process. Proper seat adjustment may result in almost perfect weight distribution before the

weight is added to the kart. You may find that after running the kart a bit, you will have a number of

mounting holes drilled in your seat to allow you to shift the seat for changing track conditions. For

example, you might move the seat forward to fight an understeering kart by more effectively transferring

weight to the front end. A good starting point for an average weight driver is to use the following:

Rear edge of upper seat back directly to the rear axle: 23cm (22.5 for a 50mm axle)

Front left edge of seat to front frame rail at the floor pan tab: 60cm

Seat bottom below frame: 2cm