Wheel fitment questions F13 M6

[Crazem4]

I have an F13 M6 coupe, I just recently purchased new wheels. Here are the specs:

Front: 20X10 27MM offset

Rear: 20X11 21MM offset

I ordered a set of (4) Michelin Pilot 4S, I mistakenly ordered 275/30 for the front instead of 275/35. The rear I'm going to run a 305/30.

What will the car look like with a 275/30 in the front instead of a 275/35? Will the fitment be off and look weird? Should I return the 275/30 and get the 275/35? I just don't want any fitment issues because of this. I was aiming for a tight fitment front and rear. If anyone has any pics of 275/30/20 in the front on an M6 it would be greatly appreciated. The car has stock suspension right now but I plan on installing H&R lowering springs very soon, if you can factor this in as well.

Thanks!

[mastatikle]

Fitment and “stance” issues are irrelevant right now. The major concern is rolling diameter. On this car, all 4 wheels/tires must have the same rolling diameter or within .5” if I remember right. Or the car will have issues depending on diameter differences. There is over a 1” difference between a 275/30 and 275/35 front. I didn’t do the calculations for the rear. But the rear tires must match whatever fronts you decide on.

Depending on the range of difference between front and back rolling diameters, the transmission will not shift right at all. the computer will think there is wheel spin and you’ll have no acceleration capabilities.

Trust me, make sure you get all calculations right prior to ordering. I’m pretty sure I’ve gone through more wheels and tires for this damn platform than anyone on here sadly. I still have tires sitting that I can’t use on anything lmao.

Btw your front offsets are off if you’re going for a “tight” fitment. Will notice it more when lowered.
Front should be around +18 for a 10” wheel.
Rear is good. Will look great lowered. I’d run a 315 in rear unless you’re going for stretched look

[Crazem4]

Originally Posted by mastatikle

Fitment and “stance” issues are irrelevant right now. The major concern is rolling diameter. On this car, all 4 wheels/tires must have the same rolling diameter or within .5” if I remember right. Or the car will have issues depending on diameter differences. There is over a 1” difference between a 275/30 and 275/35 front. I didn’t do the calculations for the rear. But the rear tires must match whatever fronts you decide on.

Depending on the range of difference between front and back rolling diameters, the transmission will not shift right at all. the computer will think there is wheel spin and you’ll have no acceleration capabilities.

Trust me, make sure you get all calculations right prior to ordering. I’m pretty sure I’ve gone through more wheels and tires for this damn platform than anyone on here sadly. I still have tires sitting that I can’t use on anything lmao.

Btw your front offsets are off if you’re going for a “tight” fitment. Will notice it more when lowered.
Front should be around +18 for a 10” wheel.
Rear is good. Will look great lowered. I’d run a 315 in rear unless you’re going for stretched look

Thanks for the advice!

I may just return all of them and get 275/35 front and 315/30 rear. Now for the front offset issue, can I fix this with a wheel spacer?

[atillathetom]

Originally Posted by Crazem4

Thanks for the advice!

I may just return all of them and get 275/35 front and 315/30 rear. Now for the front offset issue, can I fix this with a wheel spacer?

From what I see there is no offset "issue". The front fitment is actually perfect. a 10et27 will be 10mm further out toward the fender than the stock 343M. Many members opt for 10mm spacers on the stock wheel so this should be perfect. No spacer needed.

The issues is the rear is kinda in the middle. The rear will extend 4MM more than stock BUT you are going to lose 8MM on the inside which might cause a rub with a 305. Others can chime in. I would try a 10MM spacer in the rear but that might rub on the outside. That would total 14mm compared to stock which is aggressive with a 305. Might work. Since spacers smaller than 10mm aren't hubcentric that is your best bet IMHO. Others might have different opinions.

[Crazem4]

Originally Posted by atillathetom

From what I see there is no offset "issue". The front fitment is actually perfect. a 10et27 will be 10mm further out toward the fender than the stock 343M. Many members opt for 10mm spacers on the stock wheel so this should be perfect. No spacer needed.

The issues is the rear is kinda in the middle. The rear will extend 4MM more than stock BUT you are going to lose 8MM on the inside which might cause a rub with a 305. Others can chime in. I would try a 10MM spacer in the rear but that might rub on the outside. That would total 14mm compared to stock which is aggressive with a 305. Might work. Since spacers smaller than 10mm aren't hubcentric that is your best bet IMHO. Others might have different opinions.

Thanks for the info I'll try a 10MM spacer for the rear and see how that works out

[brad850csi]

I'm running 20x12 20mm with 325/30r20 and don't have a problem with the inner liner although it is close, so it should work fine as my tyres are taller and the inner edge is closer to the catr