silent_chief

So I've got a very nice Ti frame that I am upgrading the groupset on. The parts are in the mail and I'll be getting them on Wed. In anticipation I took off the cranks and removed the shimano cartridge BB. I don't remember it being particularly difficult to remove and I made sure to pull out my trusty park tool bike repair manual to run me through the process. I don't remember any brute force. The threads look fine to my untrained eye and I scrubbed them down with some degreaser, WD40 a toothbrush and some elbow grease.


As the new parts aren't in yet, I wanted to see if I could re-install the cartridge BB easily to see how the hard work on my cleaning paid off. The non drive side cup installs like butter. I can thread it on by hand easily and it seems secure. The drive side is a little tricky. I can get a few revolutions easily enough, but then it starts to stick and requires that I start to use a tool. Looking at the non drive side it appears that the axle is coming in slightly off kilter. Not wanting to force the issue I backed it out. I believe the last time I serviced this BB the same thing happened to me. I was able to thread the DS on by hand several turns and then needed to break out the wrench. Last time I didn't check to see if the axle was coming in center, so I didn't stop. However last time I was also able to screw everything down and it didn't require a Herculean amount of force and everything seemed just fine. I'm also not using a particularly large wrench. Maybe only 8-10 inches long and I'm not the strongest guy. Doesn't real damage require some real strength?


However I'm also OCD and paranoid that I have some damage to my threads. I've gone over them with a bright light and I truly can't see any obvious deformations. The threads all appear to be of uniform depth throughout the shell. I don't see any metal shavings or missing chunks. I also have some spare external BB cups for use with a hollowtech crank lying around (new cranks are going to be hollowtech as well) Curious I tried threading these on, and both NDS and DS thread on easily and firmly by hand, and only need a tool to crank them down at the very end. Once installed there is no play.


So what's the problem here? Are my threads misaligned? I never had any problems with the BB before. Is the old BB cartridge somehow off kilter? I looked at the threads on the cartridge and they seem fine. There is a tiny amount of dirt I can't seem to remove. Perhaps the answer is that this is all normal and the axle will normally straighten out as it engages into the NDS cup when I screw things down? A self correction that I didn't necessarily catch last time I did this?


Part of this is just curiosity, but part of me wonders is there something I should be doing before my new parts arrive? I've read about facing, but I don't think that will be necessary as it is unpainted Ti. I guess I could also have the threads chased? That also seems un-necessary, but what do I know. Anyways, it's raining and I'm day dreaming about my new dream machine.

dsbrantjr

Try greasing the threads (I recommend TefGel) and see how it goes. Ti has a tendency to gall and some lubrication should help. Having the threads chased could also be helpful.

silent_chief

Hmm, I think this may be it. I hadn't applied a slathering of new grease when I was putting the cartridge bb back in, as I had just spent so much time cleaning it out and just wanted to check fit. The other external BB that threaded on so nicely have never been mounted before and I think they had a thin coating of factory lubricant.


Thanks! I'll obsess a little more before the package comes and may do some testing before hand.

SquidPuppet

The fact that one BB cup goes in nicely and the other jams, that kinda points to the threads on the DS threads of the Shimano BB.

Don't do anything. Wait until you get your new parts. See how the new DS BB screws in before taking any other action. It might just float right in.

corrado33

If the axle is off center, you likely messed up the threads on the drive side. I'd recommend taking it to a shop/coop and getting the threads chased.

When installing cartridge BBs, install the NDS cup a few threads (or a lot, just as long as it doesn't stop the bb from going all of the way in), then put the DS in, making sure the spindle goes through the hole in the NDS. Tighten the DS down all of the way, then tighten the NDS.

trailangel

Nothing is wrong

silent_chief

Thanks for the replies, I'm just going to hold tight until Wed and report back. I'm pretty confident things are fine. The threads most inbound that the BB's don't touch are of the same depth/ sharpness/ etc as the ones closest to the cranks. I'm putting this down to a combo of an old cartridge and not using a slathering of grease for my test. If things go south I'll consider chasing.


Anyways, idle hands and minds on a dreary Monday and all that.

SquidPuppet

This is 99.9% the likely situation.

It's really difficult to mangle threads when removing the male component or fastener. It's foreign debris or a cockeyed approach during penetration that scars things up.

dsbrantjr

The difference between a loose-ish fit and a snug-to-tight one is a fraction of a thousandth of an inch. As long as your new BB threads in with moderate effort (fingers may not be enough) you will be fine.

wesmamyke

It could be a procedure problem than an actual thread problem. Ideally the threads would be perfect but that's really never the case.

It will almost always cause some fussing around if you install the drive side all the way first on a cartridge BB. Try installing the non-drive side first, that way you can rule out any threading issues. Next back the non-drive side off half way and install the drive side, now you can see if it's a misalignment between the two sides.

silent_chief

Wed can't get here fast enough. Didn't muck w/ the cartridge last night nut a DS external BB w/ some grease threaded on just fine.

blamester

Nothing wrong with haveing to use a tool for installation. Once a few threads are engagaed the torque required should stay more or less the same untill it is seated and then increase.
To start you can turn it the wrong way first to find where the threads engage. Once you find this point firm presssure, check it is square and then turn the correct way to engagae the first thread.
Use grease