Hi there

New member of the forum.

A6 Avant Quattro - 2018 (C7)

I was looking for a view on the following.

At a recent tyre fitting I noticed that there was a different size on the front compared to the rear. I have looked back through all paperwork and cannot see a different size referenced on invoices. It has always been the rear sizing. No idea when someone changed them

The fitters didn’t know and are simply replacing what was there. One felt that different sizes on Audis is common

So currently on the fronts I have 225/45R18/95Y

On the rear 245/45zR18/100w

My view is that they should match on a Quattro and that the fronts should be replaced.

Any views welcome and if anyone knows whether it is currently unsafe?

Thanks so much

Rich

The difference between front and rear is only the tyre widths, not the diameters, so in that respect they are safe. Whether they should be the same width in regard to wear and handling may be a different matter as I am aware that Quattros are sensitive to mismatching of tyres. I'll leave that for somebody more knowledgeable to answer.

I too wonder why narrower tyres have been fitted to the front. Was it for economy or could it have been because the suspension has been modified to need more clearance from wheel arches? It would be worth investigating the suspension before spending money on new tyres.

15 minutes ago, cliffcoggin said:

The difference between front and rear is only the tyre widths, not the diameters, so in that respect they are safe. Whether they should be the same width in regard to wear and handling may be a different matter as I am aware that Quattros are sensitive to mismatching of tyres. I'll leave that for somebody more knowledgeable to answer.

I too wonder why narrower tyres have been fitted to the front. Was it for economy or could it have been because the suspension has been modified to need more clearance from wheel arches? It would be worth investigating the suspension before spending money on new tyres.

15 minutes ago, cliffcoggin said:

The difference between front and rear is only the tyre widths, not the diameters, so in that respect they are safe. Whether they should be the same width in regard to wear and handling may be a different matter as I am aware that Quattros are sensitive to mismatching of tyres. I'll leave that for somebody more knowledgeable to answer.

I too wonder why narrower tyres have been fitted to the front. Was it for economy or could it have been because the suspension has been modified to need more clearance from wheel arches? It would be worth investigating the suspension before spending money on new tyres.

Thanks Cliff. Appreciate the response.

The definitive answer should be revealed via. consulting the handbook and/or the sticker which can usually be found on the inside of the fuel flap, or the B post.

Regards,

Gareth.

Not aware of any Audi that runs on mismatched or staggered tyre sizes. My wife runs a BMW i3 REx and it does have slightly wider rear tyres, but that’s from factory.

Only explanation, as it is odd, is the previous owner ordered tyres online with fitting and mistakenly used wrong size. Pretty sure 18” wheels are standard on C7 model. Refer to sticker on driver’s door shut for the tyres that are compatible.

Regards Quattro, yes you can overwind the rear diff with the wrong tyres.

1 hour ago, spartacus 68 said:

Not aware of any Audi that runs on mismatched or staggered tyre sizes. My wife runs a BMW i3 REx and it does have slightly wider rear tyres, but that’s from factory.

Only explanation, as it is odd, is the previous owner ordered tyres online with fitting and mistakenly used wrong size. Pretty sure 18” wheels are standard on C7 model. Refer to sticker on driver’s door shut for the tyres that are compatible.

Regards Quattro, yes you can overwind the rear diff with the wrong tyres.

Thanks Spartacus.

I have had the car from new and not sure when the change happened. Always assumed a like for like change.

Think a change back to the 245 may be needed.

R

Sorry RichD, but I would neither assume or ‘think’ anything. Just double check what was fitted on the car when it was new, before changing anything.

Regards,

Gareth.