Rear Steer

[wireflight]

Especially under strong acceleration, when one of the rear axles breaks, RWD race cars often turn sharply towards the broken axle -- e.g.: if a right axle snaps, the car will turn violently to the right. This doesn't seem to be a problem with "peg leg" cars (those having an "open" rear differential, even though such a car doesn't apply its power to both rear tires. What is the difference/what accounts for this?

I have a hypothesis that says basically it is a function of torque bias for a locking rear (the sudden shift of 50% of the power from one side to the other), but I first noticed this problem in old Indy and F1 cars. Especially in the case of F1, a locked diff seems like something that would have to be a malfunction: they make right and left turns frequently, and rarely travel in a straight line.

 

[Windsor377]

...hmmmm...I'd say torque bias would be a good guess. Most high powered Drag Race cars use a "spool" to tie the right and left rear axles together. They also use tires with a lot of traction.

The times I've seen an axle break, it has ocured right at the line, where an good N/A chassis car will leave at 3.0gs. When the axle breaks, at that instant the car will begin to pinwheel around the non-motivated wheel...in a hurry. All the torque is going to one side and not balanced by the other in that instant.

As for road race cars have differentiation and locking, the concept has been around for a while. The old Detroit Locker is one example of allowing differentiation around a turn, yet locks up both sides down the straight.

I can only guess what F1 does these days? Probably well beyond even visous lockers by now?...maybe not?...maybe some electronically controlled viscous locking?