thoughts on wheel spacers

guess i’ll let you guys know how it goes with slip on spacers, i’ve never seen hubcentric slip on spacers, if anyone knows a company that sells slip on spacers that have different inner and outer hib sizes i’d be interested.

I have seen people use these spacers without a problem, and i’ve seen people use wheels without hubcentric rings, i just want to know if anyone has any scientific reasons not to use a setup like this.