Wheel spacers have their own set of problems. If they are not hub-centric they can cause balance/handling problems.
Yup. Just ask the guy that walked six miles in the days before cell phones. I would not touch a spacer. Your wheel fits securely on the center of the disc/hub. Just the lug nuts ain't enough. I've had to hammer off a coupla wheels in my time because of that tight fit in the center but I smile each time remembering that six mile walk....

Here's a sample from a GL1800 rear wheel which has a single sided swingarm. Same is true with cars. Unless your spacer matches this design acting like a wheel on one side and the OEM hub on the other..... by then, your studs might get too short. Again, haven't been in the market for spacers for the reasons given. Maybe they fixed them?
