audifan04

I have a Quattro Audi 2013 who says that you have to replace all 4 tires and why? Why can’t I buy just 2 tires. This is for financial reasons. I’ve heard all kinds of reasons none are good.

ConfusedSkunk

I think the reasoning behind replacing all 4 at once is due to uneven wear.

When you replace only two tires, they are not worn compared to the previous tires. Geometrically this is a problem because the newer ones have a larger radius and in turn a larger circumference. The AWD system ideally wants to spin all 4 axles at the same speed (obviously not when turning), but with a "different sized" tire they would be spinning at a different rate. This is said to put stress and wear on the drivetrain.
Personally I'm not sure how valid that idea is, but it makes sense to me.

Tl;dr- Newer tires are slightly bigger, so they cause the wheels to spin at different speeds, stressing the center differential.

ConfusedSkunk

I suppose it won't cause much harm if you replaced just the two for a while, but it's not ideal in the long run due to possible wear.

snagitseven

Here's a good explanation:

https://www.tirerack.com/tires/tiret....jsp?techid=18

To avoid any damage to the Quattro system, Audi states all tire treads should be within 2/32" depth of one another. Also, all four tires should be of the same brand, type and model.

Doc@tirerack

Couldn't have said it better myself

chrislg

That all very well BUT within a few thousand miles there is every chance that two of the tyres will be more worn than the others ( depends on the driving ! ) therefore with that advice you should change those two 'more worn' tyres - even though they may still have 4/5 mms tread depth . ???
We have to live in the real world .... !

snagitseven

Different tire treads and compounds have different grip characteristics. Besides the risk of damaging the Quattro system as stated in the TireRack article, if you mix different brands or model tires (or excessive tread depth differences) and the road is wet and slippery, it could develop into a dangerous situation if one or two tire lose traction earlier than the others.

Doc@tirerack

This may appear elsewhere on the forum, but we can shave a new tire (from our inventory) down to as little as 2/32" for $25 to $30 per tire if you want to replace just one to match;


https://www.tirerack.com/tires/tiret...&affiliate=AR8

snagitseven

Yes we do but part of good tire maintenance (in the real world) is to rotate them front to back which prevents tires from wearing unevenly.

ColdCanadaRobin

We had a 2012 VW Tiguan with AWD. Got a screw in one of the tires. Recommended to replace all 4. Hell no, too expensive. Replaced both fronts, left rears with 6/32".

Only thing that happened was the fronts wore faster than expected at first, then normal wear as the tread depth got closer to the rears. No other issues. This happened at 15,000 km and those tires lasted to 90,000 km.