? about stock tire size

[jtgm3]

hey there guys, I have a 97 M3 which has 245/40 17 in the rear. I was wondering if 255/40 17 tires would fit. I heard from discount tires it would, although fall line motorsports (bmw race shop) told me it's stupid to do it because it wouldn't look right and it would kind of stick out. I'm just curious if anybody has done it. thanks

[SilverStreak]

I'm gonna move this to the Wheel/Tire Forum, but yes, 255/40-17's will fit...

[cpt97M3]

I think you will find many of us have 255/40's. My sig picture has 255/40-17's front and rear, and it's the Kumho Victoracer that runs larger than most street 255's. You may have to roll the rear fender a little, but that's easy.

Chris

[Jim@tirerack]

You wouldn't have any problem with the 255 in the rear. It has been done many times. In fact when the car first came out Michelin was having a problem keeping up with the rear tire and their suggestion was to run the 255/40R17 rear.
If I can help let me know.

[jtgm3]

How about the fronts, could I go from 225/45 - 17 to 235/45 - 17

[Jim@tirerack]

I think there is probably enough room but I would not recommend it. I have seen a lot of people go with 235/40R17 or 245/40R17 all the way around but the 235/45R17 is a taller tire.
If I can help let me know.

[FASTNEZ]

i was just about to buy my tires for tirerack when i saw this thread and was wondering, my current fronts a 245/40/17 is it wise to replace with that size again or should i go down to a 235 to increase preformance?

[cpt97M3]

i was just about to buy my tires for tirerack when i saw this thread and was wondering, my current fronts a 245/40/17 is it wise to replace with that size again or should i go down to a 235 to increase preformance?

What size wheels do you have? If you have 8.5", then the 245/40 is a good size. For the 7.5" wheel, it's better to have the 225/45 or the 235/40. 245's are really too much tire for a 7.5" wheel for best steering response.

Chris

[FASTNEZ]

its a 7.5 with the 245 on it currently, but that is what the car came with when i bought it so..... Thanks for you help i think that i will go with the 235's insted.

[Jim@tirerack]

I agree, Go with a 225/45R17 or 235/40R17 on the 17X7.5 wheel. The 245/40R17 is just too wide for the wheel.
If I can help give me a call.

[YoWsup]

if you go 255 in the rear, won't it induce more understeer than there already is? I'm assuming if you did go 255/40 in the rear you'd also go 235/40 in the fronts.

Also, does this setup work with an aftermaket suspension?

[cpt97M3]

if you go 255 in the rear, won't it induce more understeer than there already is? I'm assuming if you did go 255/40 in the rear you'd also go 235/40 in the fronts.

Also, does this setup work with an aftermaket suspension?

The stock 97's come with 225/45's in front and 245/40 in the rear. If you did nothing but change the rear tires to 255/40's, that won't _reduce_ the grip of the front, it should _increase_ the grip in the rear slightly. But many other things effect the balance of the car. I can go from understeer to oversteer by changing shock settings in less than 30 seconds. But you do have a point that it's probably best to run the same size tire on the E36 M3 F&R. For street, I run 245/40's on 8" wheels on all 4 corners. For autox, I run 255/40's on 9" wheels on all 4 corners. I sold my OEM wheels since I didn't want to run staggared wheels/tires.

Chris