I need two front tires on my A6 and I have heard various views on if the tires all have to match tread depth. I have heard that it will but unnecessary wear and tear on the transmission especially since it is AWD. As I see it right now, I am running on different tread depths between the front and back. Is this an old wives tale or something that I need to be worried about?
Not an old wives tale. This is due to the differential between the front and rear tires. More than likely it is stated in your owners manual.
You should be very worried, especially given the costs involved when an Audi is repaired.
If you think that the cost of buying 4 matching tires is expensive, wait until you get the bill for repairs to the AWD system.
My advice is to buy 4 new tires, and then to have them rotated according to Audi’s maintenance schedule. If you had rotated your current tires as per the maintenance schedule, there would not be a significant difference in wear between the front tires & the rear tires.
You don’t need 2 front tires. You need 4 tires. The AWD system on your car was designed to operate with 4 tires that are within 2/32" of tread depth of each other. Any more than that and you can cause premature wear or damage to the transfer case, which is actually a center differential. Buy 4 tires and maintain them properly and be done with it. Much cheaper than a $5000 AWD repair.
This is a good reason to rotate tires
That way they wear evenly
I have always rotated the tires on my cars at every oil change (every 5K). No exceptions. And I have had good tire life and even tread wear.
Maybe you do, maybe you don’t, it depends on what the tread depth of the rear tires is right now. You can buy a tread depth tool for about $3 for a simple one, or more for a digital one that doesn’t really work any better.
Tire tread depth is usually measured in 32nd’s of an inch. New tires can have anywhere from 9 to 12/32" tread depth. The feds determine a tire is worn out when the tread depth is 2/32" or less, although most tire people will tell you that traction in the rain becomes significantly reduced when the tread depth is less than 4/32".
For AWD, the generally accepted limit is 2/32" difference between the lowest and highest tread depth. If you are looking at high performance touring tires, the new tread depth is typically about 10/32" but that can vary a little from brand to brand. So if you are looking at new tires with 10/32" tread depth and your rear tires are 8/32" or more, you can just buy two tires.
Since the front tires tend to wear faster on FWD and AWD cars with a front bias, you want the two new tires on the front, but the tire shop may insist that they go on the rear. There are valid reasons for putting the new tires on the rear, but if the difference is 2/32" or less, then the reasons aren’t that valid and an exception can be made.
After that, monitor your tread depth periodically and anytime there is a difference approaching 2/32", then rotate the tires. In my opinion, using the tread depth as a guide for rotation is better than some arbitrary mileage. You won’t rotate as often and your tires will last longer, and you will be able to detect any alignment issues that would be masked by frequent rotation.
One other option if the two tires on your car have been used a lot, if you can’t afford 4 tires is to have the 2 new tires ‘shaved’ to match the size of the other two. But that’s shortening the lives of the new tires, better to get 4 if you can.
Everyone – Thank you for the feedback. The car is a 2005 and i have to admit that I drive it quite hard which I am sure is having an impact on the tires and I do not rotate them which is also impacting their lifespan. Texases…I hear you on the shaving, but that feels like throwing good money away.
“I drive it quite hard …and I do not rotate them”
Previously I stated that, if you don’t replace all 4 tires, you will be looking at a very large repair bill in the near future. Based on the above response, I believe that the OP will be taking out a second mortgage in the very near future in order to pay for repairing the center differential–whether he buys 4 new tires or not.
Audi repairs are notoriously expensive, and ignoring the mfr’s maintenance schedule regarding tire rotation will have a large $$ penalty as a result.
Why do people decide to ignore the maintenance schedule that the vehicle’s manufacturer compiled for them, and placed in the glove compartment?
Thanks for the feedback…tool!
You are very welcome, negligent Audi owner!!!
I’ve never understood how anything nearly as measly as a 1/16 inch difference in tread depth could pose any problem for an AWD system. Anytime the car is unevenly loaded or tire pressures out of whack, a differential has to, well, differentiate. Would driving in too many circles bust it up as well?
Unless maybe the center diff is locked for some reason (obviously no good), I don’t see how this is worth worrying about.