understanding the one-way
Front differential one-way. This has the most dramatic effect on handling. These are generally best for high-bite surfaces with sweeping, high-speed turns. When entering a corner off throttle, the front drive spins freely and isn't affected by deceleration or braking. Under these conditions, the front tires have exceptional bite, and this results in maximum off-power steering. Conversely, only the rear tires are used for braking, thus reducing rear bite. These conditions, without the proper chassis setup and tire combination, could result in excessive off-power oversteer. The rear-wheel-only braking is what makes this type of one-way best suited to high-bite tracks. The car would simply take too long to slow down, or it would be too difficult to control on a low- to medium-bite track. It's something like yanking the parking brake on a full-size car; it doesn't slow the car really quickly, and its rear end wiggles all over the place. This is also why front one-ways are better suited to tracks that allow cars to carry higher speeds through the corners where rear-wheel-only braking is sufficient to scrub off enough speed to make the corner. The car can be driven with more of a rolling motion—coasting through the corners and smoothly accelerating on to the straights more like a pan car. Conversely, tracks with 2x4 barriers outlining a series of tight, low-speed corners require very hard braking to haul the car down to a safe cornering speed—not a strong point of a one-way system.
Under acceleration, a front one-way eliminates differential action. In a perfect world in which all the tires are perfectly stuck to the racing surface, this wouldn't have much of an effect on handling. What's more common, however, especially in high-speed turns, is that the diffs will unload in the direction of the inside tires and this bleeds off power that could be used for better drive out of the corners. A front one-way locks under power and delivers 100 percent of the power to the ground.