A4 1.8t (190 ) quattro puncture

[Shadowman]

Hi all,

Got a puncture today in one rear tyre which is un-repairable. Really annoyed as the tyre still has about 5 mill tread left, but anyway, I have put the new spare on that side but obviously the rolling radius on that side will be different to the other. I am getting a new tyre fitted Tuesday ( on order ) which is a match for the spare and will only do about 20 miles between now and then, but I am worried that I will damage the drivetrain. I have heard horror stories of differentials etc being ' wound-up ' when tyres are mis-matched like this. The new tyre has about 8 mill tread, the old one approx 5 mill and I remember having read somewhere that this is just about within the tolerance allowed. I also think that the ' Torsen ' diff the Audi has, means that as long as the tyres on the same axle are within this tolerance, then again I should be o.k, but would appreciate someone who knows about these things putting my mind at ease.

Thanks

 

[GSCollie]

If you've got a full size sapre why not use it and your new tyre on the same axle and keep the 5 mm tread one as the spare. Means you won't have any problems so long you buy the same make of tyre.

 

[imported_bubstar]

[ QUOTE ]
If you've got a full size sapre why not use it and your new tyre on the same axle and keep the 5 mm tread one as the spare. Means you won't have any problems so long you buy the same make of tyre.

[/ QUOTE ]

Er....... I think he's going to do that /ubbthreads/images/graemlins/confused.gif

I don't know the answer for sure but would think by it's very design the Torsen diff' would take up the different diameters of tyre................

Maybe the handbook will help? - I'll have a look myself.

BUB /ubbthreads/images/graemlins/beerchug.gif

 

[Shadowman]

Hi guys.

As Avus says, I will leave the brand new spare on the one side and replace the opposite side with the new tyre, then use the remaining 'good' used tyre as the spare.

I think that it should be o.k, and I have lowered the pressure on the new tyre side by a few psi to hopefully bring the rolling radii even closer.

Roll on Tuesday, because I wont relax until they are both new tyres on that axle.

Thanks folks.

 

[howatsi]

How much tread have you left on the front tyres? If it is a lot less than the new rears, probably less than 4/5mm, I think you may have a problem ,because my understanding is that the torsen diif compensates between front & rear axles not left & right sides, this will cause it wear abnormally as it is trying to compensate for the different radi front & rear.
Can any techies confirm this?

 

[Shadowman]

I spoke to an Audi guy who said that the only problem would concern the tyres on the same axle. The fronts have 5/6 mill and the new rears will have 8mill so the difference is not huge, but again, if anyone knows differently, let me know.