How do i determine spacer size?

[e30loverSC]

Whats the best way to find out what size spacer you need for that particular rim? Whats is the stock offset of a 87 325is?

[StereoInstaller1]

Whats the best way to find out what size spacer you need for that particular rim? Whats is the stock offset of a 87 325is?

If you aren't using a 14" wheel, stock offset is of no importance.

[e30loverSC]

Ok on a wheel with 38mm offset how would I determine the spacer size ?

[StereoInstaller1]

You generally wanna end up at about ET15, or at least most guys do.

There is a whole thread about wheel fitment, have you read it?