Originally Posted by bigjae1976
I don't like 5mm spacers without hub extenders. If the back of the wheel bore is tapered then there is VERY little material in contact with the wheel and the hub. I know that APEX ARC8s with 5mm spacers leaves about 2mm of contact.
I think the clearance issue comes in when you have a helper spring which pushes the spring perch lower. I know KW had this issue. If you fit an 17x9 ET42 on a non-M E46s, the KWs would need a 5mm spacer whereas Bilstein and Koni (which didnot use a helper spring) would clear. I've heard of some people taking out the helper sping and then not having clearance issues...not sure how true that is or what the side effects were.
HRE uses a smaller wheel hub chamfer than OEM and other wheels so there is > 2 mm of hub engagement with a 5 mm spacer.
Yes, removing helper or tender springs and couplers helps clearance with some setups; however, with my Motons the issue wasn't due to a helper/tender spring or coupler and that's why I ended up going with a 9.5" F wheel.