Tire question 2013 A4 Quattro

Just wanted to see if I could get a consensus on what people think about replacing tires on all wheel drive systems.
All 4 tires are at about 1/2 tread life. I just noticed a bubble in the side wall of my front tire.
Do you guys think it’s ok to replace just the 2 tires on the front axle or is it necessary to replace all 4.
I called 2 Audi dealers,
1 said I absolutely need to replace tires in pairs, but if the rear tires are at 1/2 tread life there is no need to replace all 4

2nd dealer said it is necessary to replace all 4 tires because of the Quattro system.

Owners manual says tires must be replaced in pairs but I didn’t find anything about having to replace all 4

Thanks for the input

Ah yeah, always a tough question. If it were my Audi, I'd replace a pair and cross my fingers. I've always been told that intermixing different tread depths will smoke drivetrains, but I've never seen it or talked to anyone who has. I see cars come in all the time with four different brands of tires, wildly different tread depths, and no exploded differentials. Though, you gotta figure that rule came from somewhere.

Several years ago, a BMW dealer told my shop that you can replace single tires on an all-wheel-drive system, as long as all the tires are within 1mm of each other. :silly:

Yea I agree that at least the same axle should be replaced. I’m leaning toward doing that just because the owners manual only states that tires must be replaced in pairs.
Thanks for your input

No problem! I see this like a test-light-on-computer-circuits thing. We're always told it's a no-no procedure, but is it? :lol:

Yes I agree. Plus my wife’s cousin was just here and she has a 2004 Quattro. I noticed she has 3 18” wheels and 1 16” wheels on it. I asked how long have you been driving like that. She said 2 years!!!! I’m gonna say it’s probably ok to replace just 2 tires on the front expecially if the rear tires still have good tread lolol