different size tyres

[raver100]

i have only owned my 2.8 quattro for a few weeks and the centre diff had expired. just got some replacement wheels for her and while swapping the wheels (after gearbox replacement) found one of the tyres to be a 215 55 r16 on the back all the other were 205 55 r16.

Is this the reason my centre diff had gone, would it be working all the time and worn it out?

 

[Blue_Thunder]

That's less than a 2% difference in rolling radius, so I wouldn't have thought it would directly cause it, but it may have contributed.

 

[Markey]

Arnt the sizes on the rolling raduis of those wheels the same they are both 55 \ r16 the with is just different which would not make a difference at all just lower possible grip.

 

[aragorn]

The profile is a % of the width of the tyre.

so a 215 55 16 has a (215*0.55)mm sidewall, and a 205 55 has a (205*0.55)mm sidewall

 

[raver100]

The profile is a % of the width of the tyre.

so a 215 55 16 has a (215*0.55)mm sidewall, and a 205 55 has a (205*0.55)mm sidewall

so if the tyre was also new it could have been even bigger, if so would the diff be "working" all the time? as if spinning the other wheels.

 

[aragorn]

its possible, but not really that much different to having one brand new tire on one side and an nearly bald one on the other, or similarly two bald tyres on the front and two new ones on the rear.

I dont think the difference is large enough to cause the diff to lock.