BMW M5 Forum and M6 Forums banner

Rear wheels Offset equation

2076 2
Good day!

Here is what I know for sure:
1. 2003 M5 E39;
2. AC Schnitzer DFC Suspension;
3. I got wide body fenders so I don't care about fender rubbing.

What I want:
To order customs rims. 12J x 19 with 335/25 ZR19 Tires
I don't want any spacers. (no spacers)

The only thing I know about the rims I want to order is that should be 12J x 19 and 335/25 ZR19 tires but I don't know the offset .

What offset must have those rims please and why?
I need an exact number! :) They are expensive ...

Also if anybody can give me an ideea how I can find the exact offset ... maybe a local shop or so ...

Thanks in advance!
1 - 3 of 3 Posts

13,086 Posts
#1 Rule: DO NOT blindly follow any recommendations posted.

Here is what I would do:

1. Determine what tires and rims are on their now. Width, diameter, offset, section width (actual and tire mfg listed)

2. Determine how much distance you have until the tire rubs- inside and outside. Try to estimate this with full compression on the suspension.

3. Do a drawing. Figure out if that 12" wide rim with a 335/25-19 sectionwidth (hey, there is no such size...)

4. Then just adjust the offset of the new wheels based on how much you can 'encroach' towards the body AND based on the offset of your current wheels.

For example, if you currently have an 18x9.5 and there is 1" before they rub.

Stock rear has a 22mm offset.

So a 9.5" is 241.3mm. It will project towards the center 120.65mm from the center of the wheel (not taking offset into account- since you are doing 'differences between known ofsets' this doesn't matter for now.)

A 12" will be 304.8mm. The 12" will project 152.4mm from the 'midline'

152.4 minus 120.65 is 31.75mm

(An inch is 25.4mm)

In this hypothetical we said you could tolerate one inch MORE, so 25.4mm more than the stock wheel.

Since the wider wheel is actually 31.75mm further towards the centerline, you'd want an offset of LESS than 22mm... you'd want 15mm. The 7mm difference would reduce that 31.75 down to 25mm- Hence a 12" wheel with a 15mm offset would mount up ONE INCH CLOSER to the centerline.

(NOTE THIS IS JUST AN EXAMPLE, no idea if one inch is too much or not.)

Do you really 'not care' how far the wheels stick out??


663 Posts
Discussion Starter · #3 · (Edited)
Yeah, that's a good ideea.
In fact I got Hamann Daytona Beach Wide Body (is not a kit) - not installed yet - so far I have only front and rear fenders also front and rear bumper extensions and side skirts.

But I'd like to get other wheels - not Hamann - and those guys at Hamann refuse to tell me the offset for both fron and rear.
Here what I want ...

and here if a shortcut to Tirerack ...
they have 335/25/19 tires



1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.