Max change in inner wheel clearance and outer wheel position

[NickF]

Really I just wanted to know if anyone knows the max change in inner wheel clearance and outer wheel position for stock Z4M without having to customize the car, but there are a couple additional questions below...

I have a bone stock Z4M coupe that I am shopping for wheels for. I have been scouring this forum for some info on what the maximum change to inner wheel clearance and outer wheel positioning before there is tire rub, but haven’t found it. I believe the stock wheels are 18x8 ET 42 front and 18x9 ET 30 rear, and there were two sets of wheels that I was looking at. I have listed them below as well as the differences to inner clearance and outer position (that I found on one of the wheel offset calculators that was posted somewhere on this forum).


First set:
Front: 19x8.5 ET35, 1mm more inner clearance, 13mm extended outer position
Rear: 19x9.5 ET35, 11mm less inner clearance, 1mm extended outer position

Second set:
Front: 19x8.5 ET35, 1mm more inner clearance, 13mm extended outer position (same as first set)
Rear: 19x9.5 ET30, 6mm less inner clearance, 6mm extended outer position
0r
Rear: 19x9.5 ET22, 2mm more inner clearance, 14mm extended outer position


While I would like to know whether these wheels will fit or not, I guess more importantly I wanted to know if anyone knows what the max changes are in inner clearance and outer position before there is rubbing. I know that this depends on tire size (and on tire brand as well, but I can’t begin to guess what tire differences are), so I guess lets just go with the tire size that Tire Rack recommends which is 245/35-19 front and 275/30-19 rear.

Also, Tire Rack seems to think that I can put rear wheels on that are as wide as 10.5”. Is this legit? Tire Rack normally seems to be right, but 10.5” seems really wide (and actually in one case, 11”) for this car.

 

[WLH]

NickF, I can look into these later today as I don't have time right now. What I can tell you is that TireRack is very good at knowing if something will fit or not. If they are wrong and it won't fit they will take it back.

 

[NickF]

WLH... I appreciate any help... I actually wasn't going to buy wheels off tire rack, but was actually using it as a reference point for other wheels that I was looking at that were the same/similar size/offset. But doesn't 10.5" to 11" seem really wide? !0" as well...

 

[WLH]

Stock wheels for the M are as follows:

Front Wheels 8 X 18 ET 42
Rear Wheels 9 X 18 ET 30

Stock tire are as follows:
Front 225/45-18
Rear 255/40-18

Use this web site to make your caculations:
http://www.rimsntires.com/specs.jsp

First set:
Front: 19x8.5 ET35, 1mm more inner clearance, 13mm extended outer position
Rear: 19x9.5 ET35, 11mm less inner clearance, 1mm extended outer position

Using the above web site I plugged in the values for the first set getting the following results.
You can duplicate the results for yourself and then do the same for the the second set.
Front package will stick out 12 mm (0.5'') farther. Acceptable for most cars.
Rear package is 10 mm (0.4'') closer to suspension/brakes components. Acceptable for most cars.

I guess lets just go with the tire size that Tire Rack recommends which is 245/35-19 front and 275/30-19 rear.

The above tire sizes have been used by a number of forum member on 19 inch rims.

Also, Tire Rack seems to think that I can put rear wheels on that are as wide as 10.5”

With the proper offset yes. I know Mod Bargins sells CSL rep rims that they offer in 10 or even 11 inch X 19 for the rear.

Let me know if you need more help.

 

[NickF]

Thanks a lot for the info... the link you posted is amazing... way more informative than the website that I was using. I am going to do some work with that calculator. Will let you know if I run into anything else.

 

[WLH]

NickF, also instead of going to 245 and 275 tires consider 235 front and 265 rear. This combination I've been using for years with my summer tires and it works very well.

 

[NickF]

NickF, also instead of going to 245 and 275 tires consider 235 front and 265 rear. This combination I've been using for years with my summer tires and it works very well.

Ok, will keep that in mind when I put this together. Thanks again.