The other option for that size wheel is a 90-90-21. Those are the only options.

 

Time to find a new shop. Sound like the guy you were using doesn't know his stuff.

 

I really like them, they do good stuff. They're the only place near me and it's still a half hour drive. Another hour and I could find a Harley dealership, but I doubt they will mount and balance for $30.

I ended up taking the wheel and tire to a Honda place nearby, they mostly sell ATVs. They mounted it on a machine in about 2 minutes for $16, but couldn't balance it. I had the Indy Harley shop balance it, and the guy asked how I got the tire on the rim. And I told him what I'd read about the 80/90 being the same as an MH90. And he said MH90 was just slightly bigger. But he balanced it and tomorrow I'll finally get it back on. He apologized for not being able to get the tire on there, which I know they do it by hand on a manual tire changing machine, whereas the Honda guy was kicking pedals and pulling levers.

I think maybe these 21" tires are just hard to mount? I remember I had them install one or two before, same size rim, same size tire, and I remember it being a chore then too. This is my daily driver, it sitting on blocks for a week is just too damn long.

Thanks guys.