2015 A5... Wider rear tires??
#1
AudiWorld Member
Thread Starter
2015 A5... Wider rear tires??
I recently purchased a 2015 A5 S-line with the 19x9 rotor style wheels. The tires are the 255/35/19, (26" dia.) but I would like to put a set of 285/35/19 on the rear (26.9" dia). Coming from the Mustang world... are you able to stagger the rear tires or will it cause issues with the quattro drive line?
thanks in advance....
thanks in advance....
#2
AudiWorld Senior Member
Big time trouble if you do this. With Quattro or any all-wheel drive you ALWAYS strive to keep the same diameter on ALL four wheels equal. Period. Even to the extent of "shaving" new tires to match older tires if you don't replace all four at the same time.
All-wheel drive is a far, far different technology than a "Mushtang"; especially in an Audi!
Sorry if I sound terrible, but you have moved up to a far better vehicle and technology.
All-wheel drive is a far, far different technology than a "Mushtang"; especially in an Audi!
Sorry if I sound terrible, but you have moved up to a far better vehicle and technology.
#3
AudiWorld Member
Thread Starter
I agree, the Audi is a much more advanced and refined sports car... but there is nothing like the raw horsepower (450rwhp) of the supercharged Mustang 'vert I have built. That being said, I will be passing that along to my sons and daughter for their pleasure driving in the summer months, while I continue to refine my taste for Audi performance and style!
Thanks for the Quattro info... I had a feeling that would be the issue. Time to locate the proper diameter match for a staggered set.
Thanks for the Quattro info... I had a feeling that would be the issue. Time to locate the proper diameter match for a staggered set.
#4
AudiWorld Super User
The key with quattro is to keep the tire circumference of all tires within 1% of each other, otherwise the center differential will constantly be engaged and it may overheat and lock up eventually. Even if you find a combination that keeps you within the 1%, staggering tires is not a good idea. The tendency on these cars is understeer. Putting wider tires on the rear gives the rear more grip, which means it will understeer even more.
#5
AudiWorld Super User
I recently purchased a 2015 A5 S-line with the 19x9 rotor style wheels. The tires are the 255/35/19, (26" dia.) but I would like to put a set of 285/35/19 on the rear (26.9" dia). Coming from the Mustang world... are you able to stagger the rear tires or will it cause issues with the quattro drive line?
thanks in advance....
thanks in advance....
Do the math, 2/32 tread difference is essentially 4 rotations difference in a mile as shown below courtesy of TireRack:
As an example of different tire diameters resulting from tires worn to different tread depths, we'll compare two 225/45R17-sized tires, a new tire with its original tread depth of 10/32-inch and a second tire worn to 8/32-inch of remaining tread depth. The new 225/45R17-sized tire has a calculated diameter of 24.97", a circumference of 78.44" and will roll 835 times each mile. The same tire worn to 8/32-inch of remaining tread depth is calculated to be 1/8" shorter with a diameter of 24.84", have a circumference of 78.04" and will roll 839 times per mile. While the difference of 1/8" in overall diameter doesn't seem excessive, the resulting 4 revolutions per mile difference can place a continuous strain on the tires and vehicle's driveline. Obviously, the greater the difference in the tires' circumferences, the greater the resulting strain.
I happen to disagree with TireRack. If that were so all the tires would quickly wear to the same tread depth. And yet that slightly larger new tire seemed to maintain its tread depth differential relative to the other three tires (or four if you include the full size spare/alloy that came with the 2K4.2A6Q).
That being said, the S5 with sport rear diff compensates for understeer quite well even with wider tires…as long as the rolling circumference is very close to the front tires. Wider tires are ok if you can find a width/aspect ratio/wheel size=circumference closely equivalent to that of the front tires. I wouldn't think understeer is the worst problem.
#6
AudiWorld Super User
No. You could probably work with 285-35R18.
I recently purchased a 2015 A5 S-line with the 19x9 rotor style wheels. The tires are the 255/35/19, (26" dia.) but I would like to put a set of 285/35/19 on the rear (26.9" dia). Coming from the Mustang world... are you able to stagger the rear tires or will it cause issues with the quattro drive line?
thanks in advance....
thanks in advance....
99.875% or <<1%.
#7
AudiWorld Super User
That being said, the S5 with sport rear diff compensates for understeer quite well even with wider tires…as long as the rolling circumference is very close to the front tires. Wider tires are ok if you can find a width/aspect ratio/wheel size=circumference closely equivalent to that of the front tires. I wouldn't think understeer is the worst problem.
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#8
I had a S4 with 265/30/20s on the front on 9 inch wide wheels and 295/25/20s on the back with 10 inch wide wheels. I think that was a 1.8% difference in diameter. Never had a problem however, drove it 14,000 miles in that configuration. I'd recommend you take a look at the suggested tire and wheel width requirements on tire rack spec section for the tire you want to put on the rear. You may need staggered wheels too, as I did?
#9
AudiWorld Member
Thread Starter
My car does have the sport diff, and the Audi select drive. (S-Line comp pack) What I have found out is that I will need to change the front and the rears to match the overall tire diameter. It looks like a 245/40/19 and either a 275/35/19 or a 285/35/19 will be within 4 revs per mile difference and either 1/10th or 2/10ths of an inch in overall height.
#10
AudiWorld Super User
My car does have the sport diff, and the Audi select drive. (S-Line comp pack) What I have found out is that I will need to change the front and the rears to match the overall tire diameter. It looks like a 245/40/19 and either a 275/35/19 or a 285/35/19 will be within 4 revs per mile difference and either 1/10th or 2/10ths of an inch in overall height.
EDIT: Minor correction. It is available for the A8 as part of the Sport Plus Package. Seems to be the only A model in North America that can be had with the sport differential.
Last edited by superswiss; 04-26-2015 at 06:51 PM.