[S EyeLand]

I've got a set of wheels left over from my F85 that I'm thinking of using for my F90 Comp. After plugging the numbers into an offset calculator, it seems like they will fit. Could someone double-check my calculations?

I'm planning to use bolt pattern adapters from ECS Tuning and I'll also need to rebarrel the rears from 11.5 to 11 inches to address the inner clearance issue. The outer clearance is 6mm less than the stock F90 wheels, but with the 18mm adapter, this will push the wheel out 12mm in the front and 14mm in the back compared to stock. These measurements should be close to what others achieve with spacers on stock wheels.

I could buy new wheels but now I'm interested in making this work.

[johnny5ive]

not what you're looking for but got a link to that offset calculator?

[S EyeLand]

Originally Posted by johnny5ive

not what you're looking for but got a link to that offset calculator?

https://www.1010tires.com/Tools/Wheel-Offset-Calculator

[remmib]

Hi, did you factor in the change in offset when you rebarrel the rears from 11.5" to 11"?

[S EyeLand]

Originally Posted by remmib

Hi, did you factor in the change in offset when you rebarrel the rears from 11.5" to 11"?

My thinking is that the offset would stay the same and the inner clearance would reduce by the exact amount of the barrel change. Then i would push the wheel out 18mm with the adapters. Seems to all make sense in my head.

2 of these for the rears.

https://www.ebay.com/itm/22465030099...Bk9SR4LZh_izYw

[remmib]

Originally Posted by S EyeLand

My thinking is that the offset would stay the same and the inner clearance would reduce by the exact amount of the barrel change. Then i would push the wheel out 18mm with the adapters. Seems to all make sense in my head.

2 of these for the rears.

https://www.ebay.com/itm/224650300998?itmmeta=01HPFR1XHM91ZHNPTFDANV1E6Q&ha sh=item344e338e46:guAAAOSwHjNV~bjC&itmvar=enc%3A AQAIAAAA0DzLwod7QQqmuKe%2FRV5AcJA9vMmDoH5iZctapfie 1cFubVHA6F7z7vNExWJlQjerv2Kr025wJBhX6GgdlpoWu6t2bl 0451BFfe%2FblNdySIh%2FnMgK79Gn0LTadecXDJHaubBmwBpK oyoT9unzaVnmDD74t98pRBw%2FPIYRvUC7iprn9HVA3oJ1CaIB BLI6XGGNwqf1JAQqEBADhhrU0lzYiF0NmshpRN4OF7BAOWAi5K tzy648qB08Bizg%2BlzcKxETn7pNADSYp92xDi9EdpFkE70%3D %7Ctkp%3ABk9SR4LZh_izYw

Actually the offset will change since you change the centerline of the wheel. The offset will change with half of the width, so half of half an inch is 6.35mm. This means the offset of the 21x11.5 et38 wheel will change to et32 with the new barrel.

[S EyeLand]

Originally Posted by remmib

Actually the offset will change since you change the centerline of the wheel. The offset will change with half of the width, so half of half an inch is 6.35mm. This means the offset of the 21x11.5 et38 wheel will change to et32 with the new barrel.

These are 2 piece so although the centerline will change the outer to curb distance will remain unchanged and the inner clearance will be reduced by the length of the barrel reduction. resulting in 25mm increase of inner clearance.

The face includes the outer lip and outer portion of the barrel unlike traditional multipiece wheels where the face is modular and there is an outer barrel it bolts to and then and inner barrel that bolts to the outer barrel.

Here a pic of how the inner barrel meets the face/outer barrel. This is a front but if I reduced that barrel to 7.5 the only metric that should change is the inner clearance. Yea ill need to get new hardware too, but I'm going to have the wheel completely reconditioned, barrels repainted, and outers sand blasted and recleared.

[remmib]

Yes, the outer position of the wheel’s stays the same. But you can’t calculate with the same offset when the wheel is a different width. Use 21x11.5 et38 or 21x10 et32. So with 18mm adapter, it’s like putting on a 21x11.5 et20 wheel. I’ve seen pics of 21x11.5 et25 on a F90 so you don’t need too rebarrel for better inner clearance. The problem is a very aggressive outer position.

[S EyeLand]

you're right. 3mm outer extension over stock regardless of barrel. With the 18mm adapters I'll be 21mm extended in the rear over stock. so, 9-10mm more aggressive than stock with spacers. I'd have to run 10mm adapters which I don't think exist. Thanks for thinking me though this.