Shimano BB-5500 Question
 

I have an Octalink 5500 bottom bracket that's feeling a little gritty. Doesn't make sense as it's only a few months old and has no real wear on it. I pull the BB and it looks like on the fixed cup side of the bb there's a small plastic dust cap looking thing that's been mangled (there's a whole one on the adjustable cup side as well). I pull the bit out and the bb now turns noislessly (although not quite as smoothly as I'd like. not a big fan of the cartridge bearings I guess.), I pull both off and it's smoother still. So the question is am I going to have problems if I reinstall the bb without the dust cap looking bits? I'm going to give the threads and spindle a nice coat of Phils grease before I put her back in, just want to know if I'm going to have problems down the road.

that's the shimano 105 bb right? I just put one of those in my bike and Im trying to remember the dust cap thing and cant recall it?

Yeah, it's the 105 Octalink BB. Here's a question...Does your BB seem a little stiff compared to the to older non sealed cartridge bearing BB's? I seem to remember my older UN-52 spinning much more freely than the 5500 seems to.

Does it seem stiff when you scrutinize it endlessly on your bike stand or is it stiff when you're actually riding? They are great BBs and super cheap these days, 15 bucks from Nashbar. Sure, it might be a bit rougher than Ultegra, but you won't notice it whilest riding.

UN-52 and their slightly upmarket UN-72/73 brethren were all sealed bottom brackets too. They had square tapered spindles, not the Octalink splined crank interface, but they were sealed.

Are you exposing the bearings when you pull the plastic dust cap off, or are you referring to the non-drive-side plastic thing that threads into the frame to hold the BB from shifting around in the frame's bottom bracket shell?

Also, word is that square-taper sealed-cartridge BB's usually run with lower drag than comparable-quality sealed-cartridge oversized-hollow-axle BB's.

I have a BB-5500 with only 1100 miles on it, and the drive side seal itself is completely gritty and noisy.
I have futzed with it a great deal and concluded, based on the frequency of the noise per revolution that there is not much grit in there but that a small amount makes a big difference. Since reading this post I tried to pry the right side seal out with a tiny screwdriver and could not do it. I was wondering if I might get a few more miles out of it if the grit is in fact confined to the seal itself and has not made it into the bearing. My RS seal does NOT look mangles at all, it looks mint.

It is worth noting that I have never had a BB become degraded even this far until nearly 3000 miles, including a very cheap BB-LP28, which is a very low-precision boat anchor of a BB, but rolled OK for longer than the BB-5500. My Campag AC-H has 4700-ish on it and is smooth as silk though I upgraded to true Centaur recently.