Anyone Know 100%? From Experience

[S5TURBO]

I JUST PURCHASED THE A5 AND I HAVE A SET OF STAGGERED 20x9.5 WHEELS THAT I WOULD LIKE TO FIT ON THE VEHICLE. ANY SUGGESTIONS? I LOVE THE RIMS AND I HAVE NO CHOICE ABOUT THE FACT THAT THEY ARE A STAGGERED SET. IT IS ALSO NOT MY PREFERENCE BUT I LOVE THE STYLE OF THE WHEELS AND ALREADY HAVE THE RIMS PAID. MY QUESTION IS.. WHAT ARE THE BEST TIRE SIZES AND WILL THE STAGGARED RIMS FIT IN THE REAR. ALSO SHOULD I GET DIFFERENT TIRE SIZES FOR THE FRONT AND BACK BECAUSE OF THE STAGGER. ANYONE WITH ANY EXPERIENCE WITH THIS ANY HELP WOULD BE GREATLY APPREICATED.

PS. SORRY ABOUT THE CAPS. THE CAPS LOCK BUTTON IS NOT WORKING ON MY COMPUTER FOR SOME REASON.

[The RS6]

Press and hold the SHIFT button while you're typing

And, a new keyboard is available at about 10$

[another Russian]

The computer (not sure if it's the ECU or the ABS computer) has been programmed to tolerate a variance in rotational speeds between the front and rear tires (it knows each tires rotational speed because of the ABS sensors). It knows that with the car going in a straight line, the fronts and rears should be rotating at a slightly different speed from one another based on their slightly different circumference (the difference on the stock Rays wheels wearing OEM tires sizes is +2.7% (rears are 2.7% bigger than the fronts)). The reports are that the ECU can tolerate about a 3% change from this (in other words, down to roughly 0% f/r delta and up to roughly 6% f/r delta) before it starts to think there is a problem. You have you broken the 3% rule. Here's how....

Let's look at your tires sizes in comparison to the 18wheels
The tire on the stock Rays rear wheel is a 245/45-18. That tire has a circumference of 83.8 inches. The 285/30-20 you're using has a circumference of 84.0 inches, which is a difference of just 0.2%. So far so good, right? You've effectively not changed the circumference of the rear tire by going to a bigger diameter but a smaller sidewall. Now let's look at the fronts.

The tire on the stock Rays front wheel is a 225/45-18. That tire has a circumference of 81.6 inches. The 255/35-20 you purchased has a circumference of 84.9 inches, which is a difference from stock of +4.1%. Uh oh!

So, you had almost no change in circumference on the rear end when you went to the 20's, but you had a +3.3" change in circumference on the front

The end result is that there has been enough of a change between the OEM f/r variance and the new f/r variance that your computer believes a slip condition is occuring when it's actually not. Remember that with the OEM tires, the rear's were bigger than the fronts by 2.7% (we'll call this +2.7). With your 20's, the difference is that now the fronts are bigger than the rears by 1.1% (think of this as -1.1%). This is a change of 3.8%, so there's your violation of the 3% rule.

How do you fix this? Easy, drop to a 30 profile on the front tires. A 255/30-20 on the front will drop the difference from the stock tires to the new tires to just .2%, so the computer will effectively not know that there is a dfferent tire there, just like on the back. If you purchased a warranty for your tires, this might be an opportune time for the fronts to pick up some screws in non-repairable places
Hope this helps! (c)

[MPT]

I JUST PURCHASED THE A5 AND I HAVE A SET OF STAGGERED 20x9.5 WHEELS THAT I WOULD LIKE TO FIT ON THE VEHICLE. ANY SUGGESTIONS? I LOVE THE RIMS AND I HAVE NO CHOICE ABOUT THE FACT THAT THEY ARE A STAGGERED SET. IT IS ALSO NOT MY PREFERENCE BUT I LOVE THE STYLE OF THE WHEELS AND ALREADY HAVE THE RIMS PAID. MY QUESTION IS.. WHAT ARE THE BEST TIRE SIZES AND WILL THE STAGGARED RIMS FIT IN THE REAR. ALSO SHOULD I GET DIFFERENT TIRE SIZES FOR THE FRONT AND BACK BECAUSE OF THE STAGGER. ANYONE WITH ANY EXPERIENCE WITH THIS ANY HELP WOULD BE GREATLY APPREICATED.

PS. SORRY ABOUT THE CAPS. THE CAPS LOCK BUTTON IS NOT WORKING ON MY COMPUTER FOR SOME REASON.

Size of tires must be: 265/20-20".

Just make sure the wheels have a offset (ET) of around 29. And that they are "5X112" Ø66.6 mounted.

EDIT: 265/20-20" is for 9X20", but i'm 99% sure they will also fit a 9.5"

[The Pretender]

You mean 265/30R20" right. ?

Jarod.

[MPT]

You mean 265/30R20" right. ?

Jarod.

Of course. My bad :blush: .

[S5TURBO]

do You Think That The 285/30/20's Are To Wide? Or Is It A Sure Fit?

[MPT]

do You Think That The 285/30/20's Are To Wide? Or Is It A Sure Fit?

I don't think they need to be that wide, but they should fit IMO.

[Audiphile]

You have to know your offsets to begin with. What are the offsets on the 19" Rims standard on the S5 and optional on the A5? Compare that to the offset of your rims. They have to be close with the best scenerio being the 20" rims should have a lower offset than the 19" OEMs. Also, what is the bolt patterns for the A5 and S5 wheels? You will also have to perform a clearance test to make sure the wheels do not scrape the wheel well. Tire size is important here. I am not sure there is data on adding 20" rims to an S5/A5, but it should be possible.

[MPT]

You have to know your offsets to begin with. What are the offsets on the 19" Rims standard on the S5 and optional on the A5? Compare that to the offset of your rims. They have to be close with the best scenerio being the 20" rims should have a lower offset than the 19" OEMs. Also, what is the bolt patterns for the A5 and S5 wheels? You will also have to perform a clearance test to make sure the wheels do not scrape the wheel well. Tire size is important here. I am not sure there is data on adding 20" rims to an S5/A5, but it should be possible.

If you look at my post, i answar all of these problems, except the one with space; There is enough room for 265tires!