Silly question but here goes. I found a set of staggered Style 32's on Craigslist and I need to know if they will fit my 525it. They are 17x8 and 17x9. Thanks in advance.

Make sure they are E39 Style 32's (E36 ones were made). If so, you're good to go with a set of $20 hubcentric rings.

What exactly are hubcentric rings and what do they do?
I've heard them, come up a fair bit.

What exactly are hubcentric rings and what do they do?
I've heard them, come up a fair bit.

BMW wheels are hubcentric, unlike a number of other vehicles which are lug centric. This means that the weight of the wheel is distributed around the hub as the wheel rotates and not on the bolts (although the bolts do obviously take some of the load).

The rim, therefore, must exactly match the hub in diameter, otherwise you will experience shimmy and vibration as the wheel will rotate off centre. BMW, in their infinite wisdom, changed the hub diameter from 72.56 mm on E34's to 74.1 mm on E39's. Thus you need a very thin ring mounted on the hub to make up the difference when mounting E39 rims. See Pic

http://www.buywheelstoday.com/images_products/L_4474.jpg

BMW wheels are hubcentric, unlike a number of other vehicles which are lug centric. This means that the weight of the wheel is distributed around the hub as the wheel rotates and not on the bolts (although the bolts do obviously take some of the load).

The rim, therefore, must exactly match the hub in diameter, otherwise you will experience shimmy and vibration as the wheel will rotate off centre. BMW, in their infinite wisdom, changed the hub diameter from 72.56 mm on E34's to 74.1 mm on E39's. Thus you need a very thin ring mounted on the hub to make up the difference when mounting E39 rims.


Thanks for that. Makes heaps of sense =)


Is it the same for most other size wheels as well?

Thanks for that. Makes heaps of sense =)


Is it the same for most other size wheels as well?

Do you mean 17" or 18" or aftermarket? In general third party wheel manufacturers make the larger 74.1 diameter wheels so that they fit a larger number of BMW vehicles. If you can find oem BMW wheels made specifically for E34's, E32's or E38's (which also have 72.56 hubs) get them as the rings can sometimes be problematic. (plastic ones break and aluminium seize / bend) The other issue is offset (stock ET = 20 for E34) which defines the distance the mounting plane is from the centre of the wheel (inner to outer) See link for more details.

http://www.bmwe34.net/e34main/upgrade/wheels_upgrade.htm

Is it the same for most other size wheels as well?

Could you re-write the above in another way...I can't really figure out what you're asking? Is what the same for other wheels? As stated in the post above, the CAR'S wheel hub is 72.56mm (see #1 in diagram below) on all 5/6/7/8/Z8 models except the E39 which has a 74.1mm wheel hub. The BMW wheels designed for each model will have it's hub opening bored (cut) to fit the car's wheel hub. Many aftermarket wheel makers will either design their wheels with a 72.56mm hub to fit specific models...OR...cut a 74.1mm hub to fit a wide range of models and then sell hub-centric rings to cut down on having to stock wheels just for one model.

http://www.bmwmobiletradition-online.com/bmw/diagrams/m/k/4.png


BTW, the E39 is the only modern BMW that has the 74.1mm wheel hub. All other 5/6/7/8/Z8 BMWs all share the same wheel specs (except the e39's 74.1mm hub) and that includes even the newest 5/6/7 models.

The 3/Z3/Z4/X3/X5 BMWs have a different offset range (35mm-48mm) which too high for the 5/6/7/8/Z8 models.

I meant is there the same problem, and therefore need for the hubcentric rings, with most other wheels aswell?
Also, is there any way to fir the 3 series wheels on an E34, or is there a problem because of the different offset (which means what exactly?).

I meant is there the same problem, and therefore need for the hubcentric rings, with most other wheels aswell?
Also, is there any way to fir the 3 series wheels on an E34, or is there a problem because of the different offset (which means what exactly?).

You can fit a 3 series wheel onto an e34... you WILL NEED to run spacers in order for them to fit properly.

http://www.tirerack.com/wheels/tech/techpage.jsp?techid=101

Basically, a 3 series offset too is high.. therefore, the wheels will mount closer to the car.. most likely causing some rubbing issues with the struts.

Thanks for your help, I think I almost get
what the hubcentric rings, spacers and offset have to do with the wheels, and why I can't just pick up any random wheel and bolt it on.

There are 3 major things you have to watch for and consider when looking at BMW originals OR aftermarket wheels....wheel offset range, hub diameter, and wheel bolt pattern.

Again, the 5/6/7/8/Z8 BMW models share the same:
10mm-28mm wheel offset range (with the newest 5/6/7/models having a few staggered wheel set-ups with rear wheels with up to 32mm wheel offset)
72.56mm wheel hub (EXCEPT the E39's 74.1mm wheel hub)
5x120mm wheel bolt pattern


The 3/Z3/Z4/X3/X5 BMW models share the same:
35mm-48mm wheel offset range (EXCEPT the E30 & E46 M3 which has rear wheel offsets between 24mm-28mm)
72.56mm wheel hub
5x120mm wheel bolt pattern


To compensate for a wheel's larger hub opening versus your car's wheel hub size...you utilize hub centric rings to "fill" the gap:

(aluminum hub-centric rings)
http://memimage.cardomain.net/member_images/1/web/433000-433999/433594_136.jpg

To compensate for incorrect wheel offset...you utilize wheel spacers which moves the wheel further out from the car's hub:

http://www.focussport.com/images/wheelspacers.jpg

Thanks a bunch, you're awesome =)

Are there any negative effects from using hubcentric rings or spacers?

hub rings.. no.. spacers.. debatable...

hub rings.. no.. spacers.. debatable...

Yup - the bigger the spacers the bigger the debate. Personally, I wouldn't run big spacers - I just don't like the idea of another major element in the mix and (especially) the longer lug bolts you have to run. The other thing is there aren't really any 3-series specific wheels I like very much on an E24/E34.

That said, I've heard from plenty of folks who race cars with spacers and say they are fine.

Lastly, spacers aren't cheap.

Net: I'd find a good wheel that is bolt-on for E34 or just w/ $20 rings.