Basic LSD question alert

[drchris]

Regarding LSDs.

If I am parked with one wheel on ice and one on Tarmac and I try to reverse. If the ice wheel spins and the Tarmac wheel does sweet f.a. and I need pushing out (to the mirth of my friends hurling abuse at my 'useless posh car'...


What does this mean?

Regards,
Chris

[Output Flange]

It means you need winter tyres and better friends.

[rassi]

If it is relation to the E90 330D you have listed in your Garage, it would not have an LSD.

[blondini]

It means you don't have an LSD, and it also sounds like TC is switched off?

[miniman]

And that pulling the handbrake on a few clicks would see you drive away happily.

[BlitzE34]

Last BMW to have an LSD as an option was the E36 excluding M cars.

[roofer]

It means you need to edit the title to 'Open Diff'

[Dino D]

miniman said:

And that pulling the handbrake on a few clicks would see you drive away happily.

How does that work? Would it work on a fwd by applying the footbrake?
Only on an open diff or LSD too?
Sorry for all the questions but genuinely interested.

Oh and the Z3 may have been the last non-M to have an LSD as standard.

[cptsideways]

Depends on the type of diff they might have. 1 way, 1.5way or 2way or a Salisbury plate diff that works all ways. Some diffs only work forwards & not in reverse.

[Pork_n_Beem]

In that scenario, a road going plate LSD will not get you going as the preloads are too small and ramp angles to high. A rally diff will have shallower ramp angles for easier locking and generally a higher preload to avoid losing traction when say cutting a corner where you have one wheel on grass and one on tarmac or even worse one wheel on the ground and one in the air.

[miniman]

Dino D said:

miniman said:

And that pulling the handbrake on a few clicks would see you drive away happily.

How does that work? Would it work on a fwd by applying the footbrake?
Only on an open diff or LSD too?
Sorry for all the questions but genuinely interested.

Well when one wheel has no grip, all the power spins away to that wheel. Grip is just friction, so by putting the handbrake on a little you apply friction to that side of the drivetrain and thus the diff doesn't direct all the power to the "spinning" wheel.

[dtmpower]

LSDs are classified as 1Way/1.5Way/2Way , you may well have an LSD and on ice both wheels should provide drive forward if one slips. But reversing may not always act in the same fashion.

It might only 'lock up' when powered forward.