Optional size 255/40/17 on 17x8 wheels

Hi all:

I have the Composite 19 wheels on my 98 540i.
The "optional" rear tire size for my car is 255/40/17 with 235/45/17 up front.
However, all the wheels are 17x8 in front and rear.

From '99 thru '02, the 255/40/17 tire in back was mounted on a 17x9 wheel from the factory. which were either the "brilliiant line" wheel or the M-Technic Spoke 66 wheel in the 17" size. Unfortunately, there is no 17x9 version of the composite 19 wheel that was on the '97 to '98 cars.

Question is this: is 255/40/17 too much tire for a 17x8 wheel. The service tech at the dealer said that having an 8" wide wheel makes the sidewall bow in a bit where it mounts to the wheel. He said that this bowing effect makes the tire sidewall easier to compress and could compromise the steering response of the car.

Given that, I would think that if I stayed with my existing wheels, the car might actually feel better with 235/45/17 in back. Would you all agree with that?


Otherwise, the next best choice would be to go to the M-spoke 66 wheels to have 17x9 in back.

I would really love to go to the 18" M-pars for both looks and performance, but don't feel like spending $3K+ for the wheels and tires -- and I'm not in the mood to buy some lower grade E-bay replicas.

Originally Posted by Fulltone74

Hi all:

Question is this: is 255/40/17 too much tire for a 17x8 wheel. The service tech at the dealer said that having an 8" wide wheel makes the sidewall bow in a bit where it mounts to the wheel. He said that this bowing effect makes the tire sidewall easier to compress and could compromise the steering response of the car.

Given that, I would think that if I stayed with my existing wheels, the car might actually feel better with 235/45/17 in back. Would you all agree with that?

Otherwise, the next best choice would be to go to the M-spoke 66 wheels to have 17x9 in back.

The 255/40/17 will work just fine on an 8" wheel. I have run that size all around on a set of style 66 wheels (8" front / 9" rear) as my autocross set up for two years. With Falken RT-615s, the steering response was just fine and handling was much better than with the stock 235/45/17s up front.

I agree with same size all around if possible for better handling, however, I would go with the 255/40/17 all around over the 235/45/17 all around. Same size all around dials out some of the E39 understeer, gives better balance and larger is better in my opinion.

With that said, what you really need to do is buy the staggered Style 66 set I have listed in the classifieds for sale!

Originally Posted by 540cmc

The 255/40/17 will work just fine on an 8" wheel. I have run that size all around on a set of style 66 wheels (8" front / 9" rear) as my autocross set up for two years. With Falken RT-615s, the steering response was just fine and handling was much better than with the stock 235/45/17s up front.

I agree with same size all around if possible for better handling, however, I would go with the 255/40/17 all around over the 235/45/17 all around. Same size all around dials out some of the E39 understeer, gives better balance and larger is better in my opinion.

With that said, what you really need to do is buy the staggered Style 66 set I have listed in the classifieds for sale!

I don't see your ad in the classifieds.. Is it someplace other than "wheels and tires"? I'm interested if they are in clean shape.

Originally Posted by Fulltone74

I don't see your ad in the classifieds.. Is it someplace other than "wheels and tires"? I'm interested if they are in clean shape.

Here you go. http://www.bimmerfest.com/forums/sho...d.php?t=188646

I bought a set of wheels from him and can tell you from personal experience he's a trustworthy seller if you decide to buy from him.

1Dreamer,

Thanks for the kind words!

I HAD STYLE 32 ON MY WAGON, AND I HAD 255/40/17 IN THE REAR AND THE 235 SET UP IN THE FRONT AND MY WAGON ROAD GREAT AT ALL SPEEDS NO BOWING OF THE TIRE AT ALL