kreveta

When using 8,5" OEM same offset rims all way round, non-staggered, does that mean I can use 1 inch spacers (25mm) on rears completely safe?

I'm assuming this because standard setup from BMW specs is 8,5" front and 9,5" rear.

Will I also need some longer bolts? I guess not since I'm just actually filling the offset gap, not going over spec?

Thanks.

Anzafin

The only thing that a spacer does is that it pushes the wheel more out. So, without knowing the actual offset of your 8.5" rim, we can't tell how thick spacer you would be able to use. You can measure this by yourself. Measure the gap (horizontal) between the outer edge of the tire and the edge of the fender and that is the max. thickness you can go.

Of course you need longer bolts! The original bolts may not be long enough to reach the threads behind the wheel and spacer. Especially if you are going to use 1" thick spacers. On the other hand, if you want to use that thick spacers, I suggest you buy a model that is mounted to wheel hub with 5 bolts and the wheel is mounted to spacer with another 5 bolts.

- Antti -

kreveta

Thank you Antti.

Specs say to use:

front 8,5 offset 18
rear 9,5 offset 32

I'd use 8,5 offset 18 all way round, so if my math is correct I can actually use only 14mm spacers max and still be on stock size.

With this 12-14mm spacers setup I would also not need to use special longer bolts.

Right?

kreveta

Hmm... According to this calculator it's 26,7mm. Guess I was right in my first post with 1inch spacers

Anzafin

No!

If you are comparing the 8.5" ET18 wheel to 9.5" ET32 wheel it will go this way:



So the outer edge will be almost in the same position as with the 9.5" wheel. There will be 27mm more space on the inner side (strut side). I understood that you consider this 9.5 ET32 setup as a "stock", right?

However, if you're putting 8.5" ET18 wheel onto rear, you can use 15mm spacers to push the wheel out more. I know this because my current summer setup is a 8.5" ET14 wheel + 12mm spacer and it doesn't rub.
Again, using a spacer like 12-15mm, you will definitely need longer bolts!

- Antti -

kreveta

Now that makes sense! Sorry for my dumbness, I was lost but now I understand the sizing.

Basically, from the outside appearance, it doesn't matter if I use a 9,5" ET32 or 8,5" ET18 wheel as long as there is enough fender space. The difference is only 1mm from outside view.

Adding a spacer to stock configurations (matching offsets and rim widths with the specs table) will just add more aggressiveness to the appearance, while 12-14mm is generally safe and doesn't rub. Of course with longer bolts.

Right?

And so using spacers makes practical sense (or a necessity) when using non-stock configs with non-matching offset/width rim. Longer bolts than OEMs may not be always needed in this scenario.

Thank you very much for the explanation.

Anzafin

Here's a useful thread about measuring the correct thickness for the spacer:
http://www.bimmerfest.com/forums/sho....php?p=5769868

Anzafin

Yes.
Altough it can not be said that 12-14mm spacer will never rub with stock wheels. It all depends on the wheel's specs, as you figured...