So I currently run the OEM 172M staggered wheel and stock tire size setup on my 550i. I really love the OE M5 wheels (style 166M) and want to shop for a used set. One question I have is with the offset in the rear. I've noticed there are two versions of the rear 19x9.5 M5 wheel, one with ET17 and one ET28. I've also heard reference of "M5 version" and "M6 version" presumably explaining the two wheel versions out there. Which version will work on my current 550i E60? Even the ET28 M5 wheel is still less offset then my current ET32 wheel, would that be a problem?

Also, what about tires? Although the staggered rim sizes are a match to my current setup (less minor offset delta), the tire sizes are a bit different with the M5 running much larger (taller and wider) tires all around. For example in the front, the rollout different between the stock M5 tire/wheel and my current is +5%. Meaning my speedo will be 5% too slow not to mention the +4" difference in circumference and +0.6" in diameter. For the rear it's 5.3% change in roll-out with +4.3" circumference and +1.4" diameter. The M5 tires are HUGE!

Obviously I could stick to my same stock tire sizes when using M5 wheels, but would the larger M5 tires even fit, or would you need the M5 front & rear bumper to make way for the larger shoes without rubbing like mad?

E60 550i Sport 172M
FRONT: 19x8.5 (245/35R-19) ET18
REAR: 19X9.5 (275/30R-19) ET32

E60 M5 M166
FRONT: 19x8.5 (255/40R-19) ET12
REAR: 19x9.5 (285/35R-19) ET17 or ET28

 

Using M6 offset (smaller ET#) will give you the best stance (w/o the need of spacer) using your current tire sizes w/o any clearance issue since the M5/M6 tires are to tall and will rub.

 

M6 offset. I love it and have gotten nothing but compliments on them.

 

^Thanks for the input but I'm not sure I follow. Using the M6 rear offset (assuming that is the ET17 figure) would introduce a delta of 15mm! Meaning with this smaller amount of offset, it would extend the outside edge of the wheel another 15mm in width beyond the amount of offset currently used with my OE wheels.

If I use the M5 wheel (ET28) the difference in offset is only 4mm (to the outside).
http://www.1010tires.com/WheelOffsetCalculator.asp

Don't get me wrong, wider is better, but moving my rear wheels 15mm out in width would surely rub, wouldn't it?

 

Nope! Doesn't rub at all. Take a look at this photo with M6 offset.




Notice in both pictures the wheel is nearly flush with the fender. It looks fantastic trust me. With M5 offset it almost looks like someone donkey punched the rim into the side of the car. To me it just doesn't look right.

 

Your ride is awesome bro. My 166s go on Thursday!!!!!!

 

I know it's kinda hard to take for such a wide difference ... most member(s) that got M5 offset on the rear end up using at least 10mm spacer making it at ET18 ...
AFAIK for RWD E60 using ET17 on the rear is the sweet spot.

 

That's what I mean. Most people who get the M5 offset end up making a post looking for spacers later. Hahaha

Wide stance = signature BMW. It does not look out of place or improper nor does it rub. If it did, it wouldn't go on my car. I did, however, lower my car quite a bit with the H&R sport springs. I had my local body shop roll my rear fenders because with Michelin Pilot Sports (fat tires) I had a slight rub on big dips (because of how low the car was).

 

^good info thanks.. Are you running 275/30R-19 in the rear?

 

I'm using M5 M166 with 12mm H&R spacers in the back and no rubbing at all. Compliments, don't even ask!