I'm fixing up my old 1989 Fisher Montare for a commuting bike. I need to get rid of the knobbies! It now has specialized 26 x 1.95 rockcombo tires and I wish to go thinner, I'm thinking about a 26 x 1.5. Will the Araya RM 20's be ok for that?
I don't think you'll have a problem with the tires. I rode that size on Sun Ryno's.
I'm about to do the same with a bike that was rescued from the garbage. Just need North Bend style bars, narrow tires and some fenders.
'''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
I have a Trek MTB that came with 26x 2.1 knobby tires on the factory Matrix rims. I've since fitted Nashbar's house brand 26x1.25 slick tires to these rims and they work just fine. You certainly don't have a problem.
Most MTB rims can handle 26x1.5 unless it's something like a Surly Pugsley with Large Marge rims (65mm wide!). I put Ritchey Tom Slicks 26x1.4 on mine (~28mm wide rims). I think the RM20 is ~25mm wide so you can go down to 26x1.5 with no problems. 26x1.25 should even be possible, but 26x1.0 is probably too narrow.