Join Date: Mar 2008
Location: Hamilton, ON, Canada
Wheel bearings don't last forever, even if fully sealed. They operate in a somewhat harsh environment, and are quite heavily loaded. They're fairly cheap and relatively easy to replace. I replaced all the wheel and suspension bearings (i.e. shock linkage, swingarm, steering head) on my bike at around 65,000 km. Maybe some didn't strictly need it, but it's often hard to tell without removing them, at which point they're usually wrecked anyway.