Been on the same races top and bottom in my CA's since October of 2002, I've tightened them once in that time, and grease them probably once every 3-5 months. They outlasted the rubber once already, probably go through another set of rubber before I have to worry about the races. HTH
Ary
Oh yeah, I wheel in gritty mud more often than not that likes to get into anything not 100% sealed and wear it out quickly, just for reference...