How wide can 20" wheels be?

[SCCA SM]

How wide can I fit 20" wheels and not have issues rubbing?

I was looking at 20x9.5 for the front, 20x10.5 for the rear. The company im looking at makes them in .5 inch widths from 8-11 then they make a 12.

It looks like the 20x9.5 has an offset of 25mm and the 20x10.5 has an offset of 25mm or 45mm.

20x9 has an offset of 32mm or 38mm 20x10 has an offset of 45mm


Can i fit the 9.5 front wheel in front? Im fairly sure the 20x10.5 will fit the rear.

Can anyone help me with my offsets and what fits? id likely run a 285 front on the 9.5 and 315 rear. my car is lowered on H&R super sports if that makes a difference in the fitment of what clears the fenders with no rubbing at all.

thanks

 

[enormous]

If your BS is correct/ideal, the widest rear rim that I have seen is 12" running a 335.

 

[Robert M]

I have 10" Alcoa's on the front and 12" Alcoa's on the rear of my 2008.


R

 

[MattR]

Do you guys with 12" wheels have factory wheel wells? With the bump stop hacked off I could see a 12 fitting but it's gotta be crazy tight if it's all in tac .

I run 11's, no mods at all to the car

 

[Catmonkey]

Use this tool to figure out your offset for a given wheel size. I'm running an 11" wide wheel with a 61mm offset, which places the tire where the fender lip clears the sidewall on full compression with a 315/35-20 Michelin Pilot Super Sport. The only problem going to a 12" wide rim is it will slightly increase the cross section. Almost any tire you're going to be able to stuff under that wheel well will fit on an 11" rim. The guys widening Alcoa's are going to 11.75" to get to a similar offset (59mm) to what I'm running. Backspacing is critical to making big tires fit.

I removed my bump stop brackets. I have a write up on the whole process here.

 

[Robert M]

Do you guys with 12" wheels have factory wheel wells? With the bump stop hacked off I could see a 12 fitting but it's gotta be crazy tight if it's all in tac .

I run 11's, no mods at all to the car

On my 2008 I have only removed the rear shock boots and the rear brake ducts, the rear brake ducts being part of the Super Snake upgrade. I have 325/30's, I also tried 335/30's but they did slightly rub one side when I would turn up my 45 degree incline driveway and they had a little too much bulge which put them out beyond the rear fender wells. <<I was not into the "fat" look, but the 335's worked fine when driving around, it was only the turn up my driveway that was an issue, and that was only a slight rub.


R

 

[whiplash920]

just had a thread here on this...ill make it simple...11'' is the widest you can go without modifying the car. some are going to an 11.5'', others up to 11.75'', but really the true issue is whether the tire will clear and what size is approp. im running 11'' wheels with 315s in rear, 9.5'' with 275s up front.

if you go wider than 11'', bumpstop must be relocated, i would NOT just remove it, and the plastic shock boot must be cut off.

Most places ud buy wheels from shld know the offset/backspacing to use....boughtmy wheels from Modulare and they knew wthout me telling them. If i went with the 11.5'' or larger, they were not sure the backspacing to offset measurements.

Good luck!

 

[Robert M]

just had a thread here on this...ill make it simple...11'' is the widest you can go without modifying the car. some are going to an 11.5'', others up to 11.75'', but really the true issue is whether the tire will clear and what size is approp. im running 11'' wheels with 315s in rear, 9.5'' with 275s up front.

if you go wider than 11'', bumpstop must be relocated, i would NOT just remove it, and the plastic shock boot must be cut off.

Most places ud buy wheels from shld know the offset/backspacing to use....boughtmy wheels from Modulare and they knew wthout me telling them. If i went with the 11.5'' or larger, they were not sure the backspacing to offset measurements.

Good luck!

Why do the bump stop brackets need to be removed? I have been running 12's on my car for 2 years and have never, ever had any bump stop contact with my wheels while driving, not even close, not under hard squatting acceleration (rear body down), not under hard braking (rear body up), not even when twisting my car and tucking one side 12" 325/30 way into the wheel well and the other side dropped out going up my 45 degree incline drive........the only time I have to remember that my bump stop brackets are still in place is when I jack up my car and allow the axle to drop, but as long as you jack the car with the bump stop issue in mind, you jack the car appropriately for the wide wheels.......To me it was not worth cutting on my car for the few times that I jack it up per year.


If my 12's contacted my bump stops under driving conditions, then I would have to rethink this again..........narrower wheels? or butcher the car?, but since there is no issue with mine except to keep them in mind while jacking..............it doesn't seem like that major of a deal to cut on the car.





R

 

[enormous]

^ this, Robert is correct.

 

[Robert M]

I took this picture a couple of years ago, maybe even 3 years ago when I was doing my Alcoa widening project...........

Shown below is my car body supported by jack stands and my 12" Alcoa's sitting on the bump stop brackets on each side. If a persons GT500 driving habits are going to be "Dukes of Hazzard" style of driving and drop the rear wheels out like this, you are certainly going to want to cut the bump stop brackets, but this is a long axle drop for any kind of street performance driving............

^^^I guess if you put air shocks on the back and jack the body up to achieve the look shown above, that would also require bump stop brackets to be removed with these wider wheels.




R

 

[SCCA SM]

I understand that 11 inch wheels can fit, and I know that 9 inch front wheels do fit the front.

Im just wondering if the backspacing I listed in my original post will fit the car? The wheels im looking at come with those spacings for those sizes. They dont make a 20x11 in the ford bolt pattern so that rules out a 11 inch wheel for the rear.

I guess my real question is, of the wheel sizes and spacings listed, will those wheels fit?

 

[DaFreak]

How wide can I fit 20" wheels and not have issues rubbing?

I was looking at 20x9.5 for the front, 20x10.5 for the rear. The company im looking at makes them in .5 inch widths from 8-11 then they make a 12.

It looks like the 20x9.5 has an offset of 25mm and the 20x10.5 has an offset of 25mm or 45mm.

20x9 has an offset of 32mm or 38mm 20x10 has an offset of 45mm


Can i fit the 9.5 front wheel in front? Im fairly sure the 20x10.5 will fit the rear.

Can anyone help me with my offsets and what fits? id likely run a 285 front on the 9.5 and 315 rear. my car is lowered on H&R super sports if that makes a difference in the fitment of what clears the fenders with no rubbing at all.

thanks

I would not recommend 285 up front 275 max. I'd go with a 11 rear and 305's. Of course this is assuming I'd do it all over again..

G/L!

 

[BlackMachWon]

There are plenty of 5.0 bro's using 20 x 10 up front and 11" rear with no issues as well