I’m swapping parts over to a new frame. There was as expected a fair bit of dirt & grit around the bottom bracket area when I took off the threaded (GXP) cups.
Is there anything worth opening up, inspecting, possibly greasing, etc…? Or are these ‘sealed cartridge’ bearings truly sealed?
Or do I just want to clean off any obvious external grit, relube the threads, & install in new frame’s shell?
I suppose the same question would apply to threadless headset cartridge bearings.
Thanks!
In general it is fine to clean the exterior of the bearings unless you see a substantial amount of lubricant being expelled from the bearing, in which case, it may be worth while to press in new bearings.
That said, sealed bearings are somewhat serviceable. As kids we pulled the polymer seals out of our sealed skateboard wheel bearings and rinsed the grease out then shot oil in them to make them “better”. Then we had to buy new bearings with some regularity.
You can get a brand new bottom bracket on eBay for under $30, including shipping.
As far as I know you leave them alone. Wipe off external crap.
If/when the grease inside is gone, or contaminated the bearings will fail.
That’s how they are.
I’ve taken a few sealed cartridges apart and re-packed them, just cuz I have that tinkering DIY kind of streak, but honestly unless you are simply after the satisfaction of cracking a puzzling nut it’s really not worth the time & trouble relative to the cost, and there’s a good enough chance of buggering the job if you get a little overzealous with crude tools.
In one case I was able to get just the replacement bearing cartridges off eBay and re-built the rest of the BB assembly, but that was an older square-taper style and I didn’t want to have to replace the matching crankset too, so it was worth a little more hassle since I couldn’t find a whole new equivalent BB as easily. For a current model though, total replacement would be much easier and more cost-effective than re-conditioning a crunchy one.
SRAM recommends regreasing the Red BB every hundred hours of ride time or after riding in the rain.
+1 on Tom’s post.
If the bearing are “sealed” (plastic caps) on both sides then not much should get in or out. You could peel off the seals with an Xacto knife, relube, and put the seals back; but it’s not worth the effort/risk. Any local bearing distributor (look for Motion Industries, Bearing Inc. etc. in the yellowpages) will have replacements.
If the bearings have metal “shields” they can be regreased (and should be occasionally).
SRAM GXP is serviceable as opposed to Shimano Hollowtech or FSA Mega Exo. You’re supposed to pry off the dust cap, the gutter seal, and the inner seal and regrease the whole thing every 100 hours of riding. See their website for the tech doc.