I'm getting a set of wheels, that is (forgive my little knowledge on wheels), 8.5 front and 9 rear, with an offset of 30 all around. Thats what the shop told me, I don't exactly know what the 8.5 and 9 is and what in the world is 30 offset is. Anyways, the shop says, it'll fit, but I can get spacers to make it look better. They guaranteed no vibration issues, etc. Please help me out. I need to give them an answer by friday, so that they can order the spacers to be made, and order Eibach lowering kit for me.

 

im no wheel expert either.. i dunno about offsets.. someone could touch up on that. but the 8.5 and the 9 is the width of the wheel.. like for example.. 20 x 8.5 20 = diameter and 8.5 = width.

 

looked it up.. the offsets are the measured distance between the hub mounting surface and the center line of the rim.. could be positive, negative, or zero. hope i helped a little.

 

Are you sure both hubs are ET30 (offset)? Staggered wheels for an E60 need different offset for front and back really. Style 124's are ET20 (8Jx18) at the front and ET32 (9Jx18) at the rear. The 8J/9J is the width of the hub in inches.

Personally, I'd stick with the recommended BMW sizes, that is:

8Jx18 ET20 with 245/40R18 / 9Jx18 ET32 with 275/35/R18
8.5Jx19 ET18 with 245/35/R19 / 9.5Jx19 ET32 with 275/30R19

If not staggered then:

8Jx18 ET20 with 245/40R18

 

Here's another way to understand wheel offset. If the number of the replacement wheel is higher than your stock offset, say 30mm compared to 20mm stock, then the wheel will be moving INBOARD towards the vehicle by 10mm. If the offset of the replacement wheel is lower than your stock wheel, say 15mm compared to 20mm, your new wheel will be moving 5mm away from the centerline of your vehicle.

In your case it looks like 30mm offset wheels will probably be moving the wheel inboard compared to your stock wheel location, hence the possible need for wheel spacers to move them back outboard for suspension jounce clearance (and appearance).

 

Ok Thanks. If I need spacers, I'm pretty sure, there might be vibration issues. So if I want to correct the 30mm offset for these rims, so they fit the recommended specs from BMW. I should get a 12mm spacer for the front, therefore making the 30mm offset become 18mm right? How much spacer should I get for the rear wheels? Since they are supposedly offset 30 as well. I will go and check at the shop again. Please help me out more. Like how much spacer should I get to make these rims fit, any potential vibrating issues, if so, what to do to fix them? Thanks.

 

Come on guys, can anyone help me some more? About 90% of people with changed rims and none is willing to help?

 

Patience!

 

If you use wheels of a higher offset (e.g. ET30) then you need a spacer (10mm) to ensure the wheels 'stick out' appropriately. You can't go the other way!

Like I said, decide whether you want staggered (different size rims front/rear) and ensure offset as close as possible to the ones I gave you. If you don't want wider tyres on the rear ensure the rims are the same size front/rear and ensure offset very close.

Have a search for 'hub centric' on this forum - vibration can be a real issue. Best to keep to OEM wheels to be sure...

Your 8.5J/9J rims, if you must, need ET18 on the front and ET32 on the rear. So 12mm spacer on the front and the rears are near enough! (They'll stick out 2mm more than 'designed' - shouldn't be an issue, what tyres are you planning?)

 

Cole makes an excellent point. Ask your seller if the new wheels are a 'hub centric' application or not. If not, you'll need centering rings to keep the wheel centered on the hubs. To add to this complexity, centering rings can be nylon or metallic. The plastic/nylon centering rings are reported to not be as accurate in centering the wheels so try to get metallic centering rings if they're required. I recently read a thread on this forum regarding plastic centering rings on a wheel application that resulted in front end vibration since they were not absolutely true.

Sorry, can't answer the spacer vs. vibration relationship. Maybe someone who's worked with spacers can?