Is there a company that makes a 120/70-21 and a matching 180/60 or 55-17? I've been looking for and hour and can't find one.

 

Both Michelin and Dunlop make tires that will fit...

 

avon and metzeler do the 170 for the rear.... avons look wider than metzeler due to the profile of the tire(or they may actually be wider even though claim the same width). IMHO do the avons. Even though I swear by metzeler, I think avons look better. If you could tell the difference between a 170 and a 180 I'd be impressed...