Well, we got t-5 days to Moab and today I discover that it would probably be a good idea to get new bearings. I have done searches on this site and I have conflicting reports as to the size I need. My MUni is the 24# Yuni from Uni.com. I have seen OD35mm and OD40mm and ID17mm and 20mm with thinkness of 12mm? I’m leaning toward OD40mm x ID17mm x 12mm. Uni.com is closed till Monday and I’m a “now-now” kind of person.
I’ll check a bearing shop in Pueble tomorrow, with the old bearing in hand. But if they don’t have what I need, it’s gonna be rush-mail ordered, so that’s why Im hopeing someone knows the specs… and by someone I’m thinking John Childs? I’ll buy you a Guiness in Moab.
According to Unicycle.com both models of 24" Yuni’s use a Suzue hub so Darren is right - you’ll need the 40mm o.d. x 17mm i.d. x 12mm wide bearing. That would be a 6203 double sealed bearing.
If you’ve upgraded to a Profile hub then you’ll need a kind of oddball size that’s a combination of metric and inch. It’s 40mm o.d. x 3/4 INCH i.d. x 12mm wide. It’s a 6203-3/4 or something like that. Actually, Profile normally uses an inch series bearing that’s 1 5/8" o.d. x 3/4" i.d. x 7/16" wide. That’s an R12 bearing. I would imagine that those bearings would work in the Yuni frame as well. I’ve got some of all three sizes that I’m going to throw in my tool box and bring to Moab.
I keep extra bearings on hand just so I don’t have to do a rush purchase when a bearings unexpectedly fails.
If you’ve got a standard hub like a Suzue the 40mm OD x 17mm ID 6203 bearings are easy to get and very common. Your local bearing shop will definitely have them. Heck, I can even buy them at my local Lowe’s home improvement store (but they are something like $11 each at Lowe’s).
Get the rubber sealed flavor. Rubber seals work better than the metal seals for muni.
The Profile bearings are an odd size. Not anywhere near as common as the 6203 bearings. And to complicate matters there are two sizes of Profile bearings (1-5/8" OD and 40 mm OD). Best bet is to add the size you need to your next unicycle.com order and keep them on hand for when you do need them.
A local bearing supply shop might have the Profile size in stock, but prices can be expensive if it’s not one of their regular high volume bearings. The price at unicycle.com will be less and you’ll get bearings that are branded “Profile”.
I’ll buy you a Guiness in Moab.