RCinNC
Well-Known Member
I had to replace the rear wheel bearings at 61,405 miles. Only one, the non-drive side, was actually notchy, but naturally I replaced them both. There was no noise from the bearing, and it wasn't noticeable with the usual method of checking the bearing with the wheel still on. I found it during a tire change when I rotated the bearing with my fingers and it felt notchy. I believe that's uncharacteristically early for a motorcycle wheel bearing (at least one that was made by a quality manufacturer); I've never used high pressure water to wash the bike and the hubs have never been submerged, two of the normal reasons that a bearing might fail before its time.
I'm always a little dubious about the whole "add grease to a sealed bearing because the factory doesn't put enough in there". The bearings for our bike, along with a lot of other bikes, are made by Koyo and KBC, both of whom are recognized as top quality bearing manufacturers. The company that owns KBC also owns F.A.G., another world class bearing company. The engineering that goes into making quality bearings is pretty substantial, so it never makes sense to me that they would put an insufficient amount of lubrication in a sealed bearing that really isn't designed with the idea of prying open the seal and adding more. Why would they do this? If you pack grease into a confined space that wasn't designed for that much grease, seems like the only thing that would happen is the movement of the bearings in the races would squeeze whatever excess grease was in there out past the seal, and you'd be left with whatever amount of grease the designers originally intended. Worst case scenario would be that the excess couldn't escape, which means the bearings are moving through increased resistance (the excess grease that can't move out of the way of the bearings). This would tend to generate friction and excess heat, which are two more causes of early bearing failure.
Everyone's gotta do what they think is right, but I don't think adding grease to a quality sealed bearing does anything, and just adds another opportunity to allow contaminants inside the bearing that can eventually cause damage.
I'm always a little dubious about the whole "add grease to a sealed bearing because the factory doesn't put enough in there". The bearings for our bike, along with a lot of other bikes, are made by Koyo and KBC, both of whom are recognized as top quality bearing manufacturers. The company that owns KBC also owns F.A.G., another world class bearing company. The engineering that goes into making quality bearings is pretty substantial, so it never makes sense to me that they would put an insufficient amount of lubrication in a sealed bearing that really isn't designed with the idea of prying open the seal and adding more. Why would they do this? If you pack grease into a confined space that wasn't designed for that much grease, seems like the only thing that would happen is the movement of the bearings in the races would squeeze whatever excess grease was in there out past the seal, and you'd be left with whatever amount of grease the designers originally intended. Worst case scenario would be that the excess couldn't escape, which means the bearings are moving through increased resistance (the excess grease that can't move out of the way of the bearings). This would tend to generate friction and excess heat, which are two more causes of early bearing failure.
Everyone's gotta do what they think is right, but I don't think adding grease to a quality sealed bearing does anything, and just adds another opportunity to allow contaminants inside the bearing that can eventually cause damage.