I just ripped apart my mom's mountain bike's rear hub. One of the bearings was incredibly rough, so I replaced it, and the other one was smooth, but didn't turn very easily. Since I didn't have a replacement for it on hand, I just put it back, but I'm not sure if I should try to replace it. Is there a good rule of thumb on bearings? Does one failed bearing imply that another one is likely to go soon?
While we're at it, should I be doing anything to the freewheel other than cleaning it and re-greasing it? I've heard it's important not to put too much grease inside the freewheel, or it'll increase drag when you're coasting, so I was careful of that.
The specifics for this bike:
- Mavic wheels
- Shimano 9-speed freewheel
- Full suspension mountain bike that gets fairly heavy use on XC singletrack terrain