Help with offsets

[Terrance41]

I've been reading quite a bit on offsets. I would find what I'm looking for and then find another answer to contradict the one I last found. So I decided to just ask. Ok, I have a 2015 M4. The wheels that i found are 20x9 and 20x11. Now the front offset is 20. Will that be a nice flush offset for that width? I was also thinking 255/35 for that wheel. The rears offsets come in 35, and 40. Which offset would give me a nice flush fitment? I was also thinking 295/30. Thanks for tour help. Also if you have pics, please post them.

[Terrance41]

For anyone searching for this answer. I was told 20 offset on the 9" front and 40 offset with the 11" rear.

[AlterZgo]

Originally Posted by Terrance41

I've been reading quite a bit on offsets. I would find what I'm looking for and then find another answer to contradict the one I last found. So I decided to just ask. Ok, I have a 2015 M4. The wheels that i found are 20x9 and 20x11. Now the front offset is 20. Will that be a nice flush offset for that width? I was also thinking 255/35 for that wheel. The rears offsets come in 35, and 40. Which offset would give me a nice flush fitment? I was also thinking 295/30. Thanks for tour help. Also if you have pics, please post them.

I am running 20x9.5 +17 F and 20x11 +37 R with 265/30/20 F and 295/30/20 R PS4S tires. I think this fitment is pretty much spot on with no rubbing at all front or rear and my car is lowered on Bilstein coilovers.

If you are stuck on a 20x9 front, you can probably get away with a +15 offset without issue. I would NOT recommend 255/35/20 F paired with a 295/30/20 R. The front tire would be very slightly taller than the rear tire (27.02" F vs. 26.97" R). That will look whack and will cause significant DSC interventions as the car is expecting a front/rear tire stagger where the front tire is a good .6" or so shorter than the rear tire.

I'd go for 265/30/20 F and 295/30/20 R or if you want to stick with 255s, get 255/30/20 F and 285/30/20 R to stay close to stock stagger.

Here's a picture showing my fitment:

[AlterZgo]

BTW +20 and +40 offsets will fit, but it just depends on how flush of a look you want and whether you want to run wider than 295 tires in the rear some time in the future.

[Terrance41]

Originally Posted by AlterZgo

BTW +20 and +40 offsets will fit, but it just depends on how flush of a look you want and whether you want to run wider than 295 tires in the rear some time in the future.

Hey thanks for the input. So do you think I should go with 35 offset on the 11". I'm trying to stay away from having to roll etc, or have rubbing issues. And you think 5 more mm on the front? I'm just looking for a nice flush fitment. Not trying to be over aggressive etc. And definitely do not want the wheels to be sunken in. Would I get away with a 11" 35 offset with a 305/30 and be able to run the 255/35? Are the f80 and f82 take the same offsets, both cars are the same width wise? Thanks for your help.

[AlterZgo]

Originally Posted by Terrance41

Hey thanks for the input. So do you think I should go with 35 offset on the 11". I'm trying to stay away from having to roll etc, or have rubbing issues. And you think 5 more mm on the front? I'm just looking for a nice flush fitment. Not trying to be over aggressive etc. And definitely do not want the wheels to be sunken in. Would I get away with a 11" 35 offset with a 305/30 and be able to run the 255/35? Are the f80 and f82 take the same offsets, both cars are the same width wise? Thanks for your help.

F82s can get slightly more aggressive than F80s. With that said, if you run 20x11 with 305/30/20 in the back, that will likely rub if you ran a +35 offset.

There are no fenders to roll on our cars as they come rolled flat already. However, on the F80 there is a nub where the rear area of the qtr panel meets the rear bumper that can cause some rubbing. I'm sure something similar exists on the F82 as well.

If you want to run 305/30/20, I'd stick with a +40 offset. That may still slightly rub as my 295/30/20 +37 offset on 11" wide rim is very close as is.

For the front, I personally would never run 255/35/20. It's simply too tall of a tire for the front. It's 1" taller than the stock tire, which is a 255/35/19 or a 265/30/20 on a comp pack car. If you want a thicker tire than 255/30/20, go with a 265/30/20 or even 275/30/20, though people say 275/30/20 causes the steering to feel somewhat heavier.

Yes, some people run a square set up for the winter where the front and rear tires are the same size. But there is always a lot of DSC intervention. Heck even on my own car when I ran 255/35/19 and 285/35/19 (just slightly taller than stock in the back), I'd get unprovoked DSC interventions when driving slowly on or off a freeway onramp. It wasn't frequent but enough to be disconcerting. I can only imagine how much more DSC would cut in if you ran 255/35/20F and 295/30/20R.

Furthermore, that's adding a significant 1" diameter overall to the tire up front. It will be massively more prone to rubbing, particularly when you turn the wheels. As my car sits with 265/30/20, at full lock left or right, there is maybe 1/4" of space between the front and rear corners of the tire before it touches the plastic fender liner. A 255/35/20 would very likely rub quite a bit.

If you really needed to stick with a 35 aspect ratio front tire, I'd get a 19" front tire in 255/35/19 or 265/35/19 to pair with the 295/30/20 in the back. Staggered diameter rim sizes seem to be all the rage now anyway with the M4 GTS and M3/M4 CS coming stock with 19" F and 20" R rims and tires and many porsches along with the G8x M cars all have staggered diameter rims now too.

[Terrance41]

Originally Posted by AlterZgo

F82s can get slightly more aggressive than F80s. With that said, if you run 20x11 with 305/30/20 in the back, that will likely rub if you ran a +35 offset.

There are no fenders to roll on our cars as they come rolled flat already. However, on the F80 there is a nub where the rear area of the qtr panel meets the rear bumper that can cause some rubbing. I'm sure something similar exists on the F82 as well.

If you want to run 305/30/20, I'd stick with a +40 offset. That may still slightly rub as my 295/30/20 +37 offset on 11" wide rim is very close as is.

For the front, I personally would never run 255/35/20. It's simply too tall of a tire for the front. It's 1" taller than the stock tire, which is a 255/35/19 or a 265/30/20 on a comp pack car. If you want a thicker tire than 255/30/20, go with a 265/30/20 or even 275/30/20, though people say 275/30/20 causes the steering to feel somewhat heavier.

Yes, some people run a square set up for the winter where the front and rear tires are the same size. But there is always a lot of DSC intervention. Heck even on my own car when I ran 255/35/19 and 285/35/19 (just slightly taller than stock in the back), I'd get unprovoked DSC interventions when driving slowly on or off a freeway onramp. It wasn't frequent but enough to be disconcerting. I can only imagine how much more DSC would cut in if you ran 255/35/20F and 295/30/20R.

Furthermore, that's adding a significant 1" diameter overall to the tire up front. It will be massively more prone to rubbing, particularly when you turn the wheels. As my car sits with 265/30/20, at full lock left or right, there is maybe 1/4" of space between the front and rear corners of the tire before it touches the plastic fender liner. A 255/35/20 would very likely rub quite a bit.

If you really needed to stick with a 35 aspect ratio front tire, I'd get a 19" front tire in 255/35/19 or 265/35/19 to pair with the 295/30/20 in the back. Staggered diameter rim sizes seem to be all the rage now anyway with the M4 GTS and M3/M4 CS coming stock with 19" F and 20" R rims and tires and many porsches along with the G8x M cars all have staggered diameter rims now too.

Thanks bro, you helped a lot. I think I'm gonna go 20x9 20 offset +5mm spacer with 265/30. And 20x11 40 offset with 295/30.

[bmwbrad22]

Originally Posted by Terrance41

Thanks bro, you helped a lot. I think I'm gonna go 20x9 20 offset +5mm spacer with 265/30. And 20x11 40 offset with 295/30.

Which would give you a +15 offset in the front, any photos of your set up as I am having the same type of dilemma for wheels i'am looking to purchase

19x9 ET 18 just hesitant to pull the trigger

any help is appreciated!

[horsepower_and_hounds]

always better if you stay staggered that you go up in size consistently front to rear to maintain good OEM designed handling. Ex: from 9/10 to 9.5/10.5 etc