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[zsx_m]

I've decided to take the plunge and try out 20" wheels, my M3 is not a DD, and I have put 2k miles on since I picked it up in March. I have ordered the wheels and am trying to pick out the perfect Pilot Super Sport tires.

My two biggest fears with 20" tires are 1.) raising the overall height of the car, and 2.) running a "rubber band" tire. So I'm trying to come as close as possible to the overall diameter of the stock 19's - but before I order I would like someone to check my math

Stock 19" front: 245/35/19 = Overall Diameter of 25.75"
Stock 19" rear 265/35/19 = Overall Diameter of 26.3"

Replacement 20" front: 245/30/20 = Overall Diameter of 25.79"
Replacement 20" rear: 275/30/20 = Overall Diameter of 26.5"

Thanks if anyone can help!

[r53s65e90]

Originally Posted by zsx_m

Replacement 20" front: 245/30/20 = Overall Diameter of 25.79"
Replacement 20" rear: 275/30/20 = Overall Diameter of 26.5"

I usually use tirerack.com for stuff like this. Attached is the data for Hankook Ventus V12.

I have PSS 255/35 19 and 275/35 19 with 26" front and 26.6" at the back. So you should be OK.

[zsx_m]

It looks like my math was correct.

Would there be any negative effect to running the 275's on all 4 corners?

[SUBFRAMERIPPER]

275's on all four??? What are the specs on the new wheels?

[zsx_m]

20x9.5 F & 20x10.5 R

[991brothers]

I am running the same exact set up. I rub in the front though.....

[zsx_m]

Originally Posted by NavidM3E92

I am running the same exact set up. I rub in the front though.....

That sucks but damn..your car looks perfect

[Technic]

Originally Posted by zsx_m

It looks like my math was correct.

Would there be any negative effect to running the 275's on all 4 corners?

You will be running a 2.8% greater diameter in the front, not advisable.

[Bart@AUTOcouture]

275/30/20 on the front will be trouble.. and it will also look off when you have the same rear tire on a wheel that is a full inch wider.

go with 245/30 and 275/30.. I've done it on many sets and it is ideal.

[zsx_m]

Thanks for response - this is why I'm a little confused.

Wouldn't there be more of a dramatic difference in sidewall height between the 245/30/20 and 275/30/20? Does the width of the wheel make a difference in the look of the sidewall? Sorry for my ignorance here and thanks again for your help.

[SUBFRAMERIPPER]

I run 255/285 on 20x9 20x10.5. Some of the 245/30 tires do not meet the recommended load requirement. Depending on your offset you should be allright with a 255/30 on the front.

[slicer]

I personally wouldn't run 20's on an M3 (I have done so in the past and would not do it again). It results in a compromise in performance and I frankly don't think they look better. Lose - lose situation. Putting that aside, I would run the tallest sidewalls that I could with 20" wheels in order to reduce the negative impact.

I would either run 255/30 or 265/30 in the front. The 255/30 will rub slightly at full lock and the 265/30 will most certainly rub at full lock. I would probably want to run Michelin PSS which isn't available in 255/30. That would make you have to choose between 245/30 and 265/30. I would choose 265/30 and deal with the rub - especially since you have 9.5" wheels. I think most people would go with 245/30 or 255/30.

In the rear I would run 285/30 or 275/30. 285/30 being my first choice. That is unless I had a really wide rear wheel (11" or 11.5"). On a wide wheel I would probably run 305/25.

[SUBFRAMERIPPER]

Originally Posted by slicer

I personally wouldn't run 20's on an M3 (I have done so in the past and would not do it again). It results in a compromise in performance and I frankly don't think they look better. Lose - lose situation. Putting that aside, I would run the tallest sidewalls that I could with 20" wheels in order to reduce the negative impact.

I would either run 255/30 or 265/30 in the front. The 255/30 will rub slightly at full lock and the 265/30 will most certainly rub at full lock. I would probably want to run Michelin PSS which isn't available in 255/30. That would make you have to choose between 245/30 and 265/30. I would choose 265/30 and deal with the rub - especially since you have 9.5" wheels. I think most people would go with 245/30 or 255/30.

In the rear I would run 285/30 or 275/30. 285/30 being my first choice. That is unless I had a really wide rear wheel (11" or 11.5"). On a wide wheel I would probably run 305/25.

What Slicer said is right on.

245/275 with a 30 profile with the sizes you have is too small.

You can run Vreds. They make a 255/30/20. You can run the 255/285 setup.

[808MGuy]

I run 255/30 on a 20 x 9 in front and 305/25 on a 20 x 10.5 in the rear. No rubbing with PS2s. I used to run 255/30 285/30 Vreds and that setup didn't rub either. The sidewall on the 285/30 is taller but I like the width of the 305/25. The roads here are pretty bad but my wheels (HRE P40) have held up well.

[zsx_m]

I ended up going with a 275/30/20(R) and 255/30/20(F).

I think this setup is absolutely perfect. They are ice skates now that it's cold, but my car is pretty much garaged for winter in the north east anyway. I don't know why so many complain about ride harshness, I actually thought the car was too soft on stock tires, but maybe I'm crazy.

I cannot imagine ever changing this setup except for performance reasons, the car is technically slower.

[squartus]

Yea if I had it to do over id never buy 20inch wheels but would of went with 19inch like I wanted from get go. They look freaking good but on a 11inch wheel your just to screwed on the sidewall thickness.

[slipaway37]

I am running 20x9" & 20x10.5" wheels with 255/30/20 & 285/30/20 Bridgestone RE760's. I am also dropped and have ZERO issues what-so-ever.
I love my setup.

[demonglide]

I run
305/25/20 rear
255/30/20 front
Works awesome hope this helped
I'm running Hankook EVO Ventus.

[Jremmy]

Originally Posted by Pertplus

THIS lol