Kyosho SIL300000 Silicone Differential Oil #300000 40cc

Kyosho silicone differential oil in the #300000 grade, supplied in a 40cc bottle.

This is a heavy gear differential oil, one step lighter than Kyosho's #500000. Gear diff oil weight is one of the most effective tuning tools available on a four-wheel-drive or center-diff car, because the thicker the oil, the harder it is for the differential gears to rotate relative to one another. As Kyosho's dealers put it, the thicker the oil, the less your differential will diff out in the corners.

Going heavier locks the axle up more on corner exit and puts drive to both wheels rather than letting the unloaded one spin, which builds forward traction on low-grip surfaces and adds stability off throttle. Going lighter frees the car up and gives you more steering into and through the corner.

#300000 is a common center or front differential choice for drivers who find #500000 too aggressive and want to keep some rotation on corner entry. Silicone oil holds its viscosity as the diff heats through a run, so the balance you set in practice is the balance you get in the main.