chiark

Hi all

My car has stood for a week and the rear right wheel locked (I put the handbrake on - silly boy).

I drove it out of the garage with the wheel completely locked as I could not rock it free, so for about 4 yards the wheel was not turning whilst everything else turned.

On the drive, I tapped the wheel with a block of wood, and rocked forward/backward for bloody ages until it went "plonk!".

Everything feels fine, but I'm worried that I could have done something bad to the rear diff, if nothing else. The car accelerates straight, brakes straight, the handbrake works on both rear wheels, and drives as it did before, so I think I'm OK, but I'm no mechanic.

Can anyone put my mind at rest, or tell me what to get checked out? My car is a UK spec MY00, and I am not quite sure what type of diff it has so I don't know whether I could have damaged it or not.

brickboy

For such a tiny distance (driving out of your garage), don't worry, there'll be no damage as you're at almost zero speed and zero stress on the drivetrain. The diff is meant to handle different rates of wheel rotation and cornering stresses.

I've heard that things like running fast over long distances with a spacesaver spare tyre etc can cause diff problems, but what happened to you will cause no damage. It's certainly no worse than driving off with the handbrake on -- which we've all done (haven't we???)

chiark

*hugs brickboy*

Cheers, I was hoping as such, especially using such a small distance. Paranoid? Me?

Cheers!

Nick.
(happy)

Adam M

Why does space saver driving make a difference?

My space saver has the same circumference as my normal wheels and tyres.

Nick, I do agree witrh brickboy. If it was a normal diff, then that is what it is designed for.

A limited slip diff will lock when there is too great a speed difference between the rear wheels. Had this happened, then both rear wheels would lock and the torque from the whole rear axle would be attempting to release your locked wheel rather than just the drag from the friction of the tyres, So either way it would not have been a bad thing.

chiark

Cheers Adam, I couldn't remember what the conclusion was regarding whether or not the UK had an LSD. I remembered what an LSD did from our conversations - cheers for that, most appreciated - so was rather concerned that if it had one, I'd have done some damage!

brickboy

Adam, I remember reading somewhere that some cars have space savers that are different diameters to the normal road wheel. At much more than the recommended 56mph, the poor diff starts thinking its going round a permanent corner and can apparently start getting very hot ... notwithstanding the lack of grip from a 135-section tyre ;-)

Adam M

I dont disagree at all that if the diameters were different the diff would certainly get hot, I was only saying that I thought my space saver was the same diameter.

I dont think I would be comfortable going over 50mpn on a space saver either.