BBS Offset/fitment quick qeustion

[DinanDave]

I was wondering if you all could help me with a wheel fitment issue?

I just picked up a set of bbs rs splits for my e36. They are 17x8 et 20 with a one inch lip currently. I'd like to go with a 2 or 2.5 inch lip in the front and a 3 inch lip in the rear. Is it doable? And what would the offset be? Would I need spacers to make them fit?

[electricalbox]

I was wondering if you all could help me with a wheel fitment issue?

I just picked up a set of bbs rs splits for my e36. They are 17x8 et 20 with a one inch lip currently. I'd like to go with a 2 or 2.5 inch lip in the front and a 3 inch lip in the rear. Is it doable? And what would the offset be? Would I need spacers to make them fit?

Simple math man, since you posted up so many options I don't want to do it for all. If they fit now why would you need spacers? Adding a lip is extending the wheel out not in, spacers are in fact opposite of what you may potentially run into lowering the offset by adding a larger lip.

[DinanDave]

So no spacers then. I'm leaning towards a 2'' front lip and a 3'' rear lip does adding a larger lip change the offset?

[electricalbox]

Of course it does a larger lip will lower the offset.

Please search, this forum lately is just a bunch of people asking the same damn questions every 2 minutes. Here I searched on this website for 30 seconds and found this, not to mention google has a billion results as well. No disrespect, but people you will actually learn something if you pursue it rather then asking for it to be handed to you.

http://www.stanceworks.com/forums/showthread.php?t=3145

[DinanDave]

Thanks for you insight or whatever you want to call it. I was asking a simple qeustion. The thread you posted was of no help to me nor does it answer my qeustion.

[electricalbox]

Yep it doesn’t have the answer at all (taken from link)

“I have noticed for every .5" you go out (pattern), while maintaining the same inner position/clearance, you will lower your offset by ~6mm (6.35mm to be exact (25.4 / 4 = 6.35). I have also noticed the outer position will go out 12mm (using the calculator, it gives you 12mm) (12.7 to be exact; 25.4 / 2 = 12.7)).”

OK since you really want it handed out here it goes; once again I will reiterate this information is easily found on google in a few seconds and/or a simple grasp of high school mathematics, hopefully it serves as a reference point for all others who ask and can't find the hundreds of discussions on this exact topic.

Your wheel is 8” wide (bead to bead, not edge to edge). Your offset is 20mm, offset can simply be thought of as how much the hub mating surface of the wheel is offset from the center line of the wheel. Since your wheel is 20mm positive offset, that means that the hub mating surface is just 20mm (.79”) from the center (4”) of your wheel. Now if you want to increase your wheels lips, you will effectively be creating a new center line for your wheel. If you replace your 1” lip, with a 2” lip you are now left with a wheel that is 9” wide and a center line of 4.5”. Since the wheel is now 9” wide and you increased the size by only adding to one side of the wheel (outer not inner) the offset will change .5” or 12.7 negatively leaving you with an offset of 7.3mm.

I even made up a paint picture to illustrate it though not exactly to scale its pretty good, and included another link with just the answer.

http://forums.bimmerforums.com/forum/showthread.php?1074863-Widen-3-piece-wheels-how-to-calculate-offset