Cheat Sheet : Setup Changes for Oversteer and Understeer

The sections below explain the theory behind setup changes, but this section is just a handy list (or cheat sheet if you will) of what changes to make for understeer and oversteer.

There are many approaches you can take, and it may not always be clear what to start with, as it depends on so many things such as are you on corner entry or corner exist, on or off power. If you are on corner entry off power then often changes at the front of the car are where to start as the impact of changes tends to be bigger. If you at a corner exit on power then often changes at the rear of the car are where to start as the impact tends to be bigger. However, these are not strict rules, and understanding the entire corner and how a change to affect corner entry does or does not affect mid corner or corner exit is how you can start to make your decisions.

For example, if I want a more stable initial corner entry but want more rotation in the middle to corner exit, reducing the rear camber can achieve all of this. If makes the car more stable on that initial corner entry until the rear fully loads up at which point you start to get more rotation towards the middle of the corner and carry it through the exit. So, the point is to think about how a change affects the entire corner.

Setting	Car has Oversteer	Car has Understeer
Front Spring	Stiffen	Soften
Rear Spring	Soften	Stiffen
Front Swaybar	Stiffen	Soften
Rear Swaybar	Soften	Stiffen
Front Camber	Less Negative	More Negative
Rear Camber	More Negative (1)	Less Negative
Front Ride Height	Raise	Lower
Rear Ride Height	Lower	Raise
Front Shocks Low Speed Compression	More Dampening	Less Dampening
Front Shocks Low Speed Rebound	Less Dampening	More Dampening
Rear Shocks Low Speed Compression	Less Dampening	More Dampening
Rear Shocks Low Speed Rebound	More Dampening	Less Dampening
Front Toe out	Increase (2)	Decrease
Rear Toe In	Increase	Decrease

For the rear diff we need to break things down to when you are on or off power.

Setting	Car has Oversteer Off Power	Car has Oversteer On Power	Car has understeer Off Power	Car has understeer On Power
Diff Preload	Increase	Decrease	Decrease	Increase
Diff Clutch Faces	Increase	Decrease	Decrease	Increase
Cost Ramp Angle	Increase	n/a	Decrease	n/a
Drive Ramp Angle	n/a	Decrease	n/a	Increase

• (1) For the rear camber, normally if the car is loose you will increase rear negative camber, however there are times, like at the early stages of corner entry before the car has reached its full lateral load where decreasing the camber can give you more grip. The cost will be that once you reach the full lateral load then the rear will become more loose.

• (2) In general, the change listed above for Front Toe-Out works best, but you might go the opposite direction if you want to affect just that very initial turn-in. This is because more toe out will give you more very initial turn steering in but give you less steering through the remainder of the corner.