Replacing a single tyre with quattro

[ukgroucho]

Well once again I had a tyre pressure inflation warning, although this time it was not 'generic' (which was caused by cooler weather dropping the pressures) it was specific "Rear left tyre underinflated".

Got a screw head sticking out on the edge of the tread and is not repairable according to the local tyre place.
I've done just shy of 5k miles so I'm hoping that I can get away with just replacing the damaged tyre....

Anyone got any views, advice, experience with having slightly different degrees of wear on tyres on a quattro? There seems to be conflicting advice on the web depending on the quattro mechanism (haldex vs. torsen).

[Guest 2]

As long as they're the same brand/type/tread you'll be fine.

[razor77]

As long as they're the same brand/type/tread you'll be fine.

Personally I prefer full depth tread. The depth displaces water so wouldn't each tyre displace a differnet amount of water? Also this would then require maintaining your tyres out of sync... I wouldn't choose to do that.

Do we have full size spares? I just tried to Google and I read its an option?! I'd check but it's wet and dark and the boots full. If we do have full size spares (with the same tyre) use that with the new one, and put your 5k part worn on the spares.

[SMILEMAN]

I had a "return to manufacture-major repair" done when in a similar situation a while back.
Only disadvantage is you have to be without the tyre for 10 days and it cost about £30, but on a nearly new tyre I thought it well worth it. Came back fine.
Little local places don't publicise this as they want to sell you a new tyre, we have Micheldever Tyres near us that are a major tyre retailer and they were quite happy to arrange it.
Another option??

[Passatier3]

I don't think UKG is concerned so much with replacing the tyre with a new one, it's replacing it and having a slightly different diameter to the one on the other side of the car.

One would have thought that manufacturers would have factored this into the design of the car given that it is a fact of life that folks have punctures and sometimes have to just replace one tyre.

I guess (and it's just that) that the diff will compensate in the same way as when going round corners? And as we are rarely, truly driving in a straight line for long it shouldn't be an issue?

[Guest 2]

It's not the first time I've put a brand new tyre on my A6 when the others are 40%+ worn. No issues over the past 4 years.


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[ukgroucho]

Yes concerned about different rolling diameters... the users manual suggests that they should be the same although that is impossible over the life of the tyres even if you rotate front and rear every 10 or 15k (which they suggest that you do).

I'm hoping that the <5k I've done will not result in too much of a disparity on the rear axle ... the rears wear more slowly also.

[Johnb80]

Well once again I had a tyre pressure inflation warning, although this time it was not 'generic' (which was caused by cooler weather dropping the pressures) it was specific "Rear left tyre underinflated".

Got a screw head sticking out on the edge of the tread and is not repairable according to the local tyre place.
I've done just shy of 5k miles so I'm hoping that I can get away with just replacing the damaged tyre....

Anyone got any views, advice, experience with having slightly different degrees of wear on tyres on a quattro? There seems to be conflicting advice on the web depending on the quattro mechanism (haldex vs. torsen).

It makes very little difference, I've just put some figures into a spreadsheet and at 60mph with 3mm of wear the difference of wheel RPM is only 8rpm, I'm sure the diff(s) will cope with that.

John

[Passatier3]

Was thinking about it some more and in reality the rolling diameters are rarely going to be the same anyway as due to camber of road/weight transference, varying loads and their distribution within the car etc. then particularly with camber the tyres on one side are going to be squashed a little and on the opposite side are going to be extended a little.

As said at the mileage done there shouldn't be too much wear and visually and with regards to water clearance the difference should be negligible.

[ukgroucho]

Thanks for the replies folks.

tyre changed today and so far it seems fine... As predicted. I did ask about the return to manufacturer repair, on the basis I could store the tyre somewhere for a "rainy day" but the small local tyre place claim they don't get involved in that kind of stuff. Faced with having to work out how to do it, ship it (£20?) pay for repair (£30?) and return shipment ... And never be quite happy with the tyre, I decided to abandon it.

for the heck of it I asked the tyre fitting guy to measure tread depth on the worn and new tyres... 7mm and 8mm so just 1 mm difference.

the only thing that did bother me was that my trip mpg (100 miles or so to Bracknell)... For a journey I have done 3 or 4 times in the last 2 months was at least 1 mpg down, but hardly scientific based on one trip so I will monitor and report back anything that seems out of whack.