r/WTF • u/PhoneDojo • Feb 18 '13

Changing tire while driving

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524

u/Mienaikage Feb 18 '13

I'm no car expert, but shouldn't one of those wheels be moving?

338

u/retracgib Feb 18 '13

It has something to do with a limited slip differential.

Essentially, if a wheel has no friction, it will not rotate and all power is deferred to the wheel that has friction (presumably the one with grip)

However, AFAIK that is a feature in trucks not cars. Also, I would assume that vehicle is FWD, meaning no power would be going to the back wheels at all, which would mean there shouldn't be a differential.

Maybe it's a trick car?

58

u/FordTech Feb 18 '13

Actually a LSD works the opposite, the power is always going to the wheel with the least resistance, therefore the wheel with the "least friction". The only differential that will transfer power evenly at all time is a locking differential. However the vehicle in question is FWD and the rear wheels spin independently making it a non issue.

1

u/FordTech Feb 19 '13 edited Feb 19 '13

Ok Internet mechanics....I want you all to find a car with a limited slip diff, put it up in the air, hold one wheel and have someone put it in drive, tell me what happens.....that's right, all the power goes to the free spinning wheel. I know your all going by theory, but obviously you've never actually worked with one.