Don't worry about oversteer or understeer you need to experiment and try different setups yourself untill you find what you like. Here is a similar post I made quite a while ago when my name was little stampy. I made a few changes to it but its the basic rule of thumb showing how a buggy will handle to different diff settings.


ORIGINAL: Little Stampy

Front- thicker gives you less steering responce off throttle and better on throttle "posi" traction pull out of corners because of the even power to both wheels but it could give you slow steering responce off throttle. Lighter oil gives lots of off throttle steering responce because of the low resistance between how fast each wheel spins but less front wheel bite out of the corners because the power gets thrown to the wheel with the least traction instead of having both tires bite into the dirt.

Center- thicker gives more 4wd which can give you some under steer because the rear is pushing the front tires a long to much but great drive with all 4 wheels accelerating the buggy hard and thinner oil will give you a lot of power to the front wheels so it pulls the buggy around on the throttle more giving you good on throttle steering but lacks a little acceleration because mainly the front tires are pulling instead of all 4 digging.

Rear- thicker will give you understeer off the throttle because of the resistance between each wheel spining to the other but as long as your on the throttle and have the tires broken loose of traction it will of corse bring the rear of the buggy around but you can't always break the tires loose like that which can make handling inconsistant... thinner oil will give you quick steering because of the low resistance that will let each wheel spin however fast they need to and it will give you a hard time to break both tires loose under power because all of the power goes to the tire with the least traction which is the inside tire. All in all the rear is only a rudder... if the rear diff weight is to light then the rear of the buggy feels like its swinging in the wind. If its to heavy the rear feels like a big ancor.