invalid.user

Hello everyone,

I have a new bike that is ridden probably less than 50km total. I decided to upgrade my crankset, since it is using an older version (Shimano FC RS-510). I purchased a Shimano FC R7000, but while upgrading, I noticed that the cap on the bottom bracket was broken. I purchased a new press-fit bottom bracket (SM-BB92-41B) and installed it. I installed the new crankset, and everything went smoothly. After I was done, I was taking a look at my work, and noticed that the bottom bracket on the non drive side had a TINY bit of gap between it and the holder (like a fraction of a mm), but I decided since I know how to do it, I might as well put the press back on and press it a bit more. This is where things went wrong. I took off the crank arm normally, but when I tried to take off the crank, it just would not come out. I tried tapping it from the non-drive side, I tried spinning it while pulling, etc. Nothing work. It spins very smoothly, so it's obviously not jammed or anything, but I'm thinking since I added so much grease to it, it formed an air tight bond with the bottom bracket and the suction keeps it from coming out. I eventually gave up and reiinstalled the crank arm, since the space is so miniscule, I figured it's not worth it. However, it keeps bothering me every now and then, and I've removed the crank arm and attempted to take out the crank 4 times since then with the same failure that ends up in me putting everything back together and calling it quits. Keep in mind that the weather here doesn't permit me to ride the bike, so during all of this, the bike is just sitting at home (I keep it in my room, so it's not exposed to the cold). I'm worried that hitting he crank any more forcefully will result in damage to it, the bottom bracket, or the frame. Should I just leave everything as is and see if there are any issues while riding it? (I don't anticipate there would be considering the bottom bracket is like fractions of a mm out; almost imperceptible unless you look really really closely), or do I have to take it apart and press it in more? If so, how?

TL;DR: Press-fit bottom bracket is fractions of a mm away from being fully pressed (almost imperceptible unless you look really closely. a piece of paper would not fit in the space, crank installs normally with no rubbing or anything, and spins freely. There isn't any noise coming from crank or BB). Crank is stuck and refuses to come out, although it spins freely. I'm therefore unable to remove it to press the BB in further. I've tried tapping it with a hammer from the other side, spinning it while pulling, etc. Nothing works. Is it ok to keep things as is or do I absolutely have to take it apart and press the bottom bracket in more?

Solution for anyone else having this problem in the future: Place your old bottom bracket around the exposed part of the spindle and insert it so that it is touching the installed bottom bracket. Hit the old bottom bracket with a rubber mallet a few times, and it'll push in the installed bottom bracket all the way in!

Iride01 

New members can put the URL of the location of your photos in the text of your message and then put a space on either side of the . and remove the https://. Then it's not longer a URL, but most of us have at least enough smarts to figure out how to make it work again.

dsbrantjr

Never Fix A Running Piece

invalid.user

I've seen enough 'new members can't post photos' that I assumed it was against the rules. I'll add photos when I go back home (out of town atm) on Thursday. I doubt it would be visible on camera, however, so I'm not sure how much photos would help :/

Thanks. This is what I'm leaning towards currently, but I wanted other people's more experienced input. I appreciate it.

Iride01 

No, the no photos thing is more about spam control. It's just unfortunate that there isn't a good way to determine programmatically with logic if a user is a spammer or legit. So for high volume traffic sites like this is, it's necessary.

But I've been telling other newb's this for years. No administrator or mod has ever said not to. And to my knowledge the SPAM police have never showed up at any newb's door that was so inclined to defeat the spam filters.

Crankycrank

You may need to give the crank spindle a medium whack to get it out. Not uncommon with some setups. Put a wood block over the end of the spindle and give it progressively harder hits until it comes out. Use your common sense of course and don't use gorilla strength with a 20lb sledgehammer.

invalid.user

This is what I've tried so far, but unfortunately, it will not budge I'm scared to hit it any harder as it seems like something will break if I do. The space between the bottom bracket shall and the housing is small enough that a piece of paper would not fit there. With grease applied, it's impossible to see. I was wondering if anyone has any experience with this and could tell me whether simply leaving it like that will be ok or whether I MUST press it further. I'll post pictures tomorrow night when I get back home, but I don't think the gap will be visible in a photo.

AeroGut

As long as the bb isn’t binding on the crank, there’s no need to “fix” it. Just keep an eye on it that it doesn’t start to work itself farther out.
If you decide you must get it all the way in, just hit it harder as others advised. It’s rare that “Hit it harder” is the right answer, but this is one of them. Crank spindles are really strong, so you’re not likely to break anything

cxwrench

If it ain't broke, fix it til it is.

Litespud

Is the gap consistent all the way around? Maybe the BB shell wasn't properly faced, so it's not perfectly flat and perpendicular to the BB axis (winging it here - not too familiar with press-fit BBs). Could it have always been this way but you never noticed before?
BTW if you installed the crank through the BB, you know there's nothing specific holding it (the "suction" theory is imaginative, but unlikely). Hit it harder, with a dead blow mallet and/or a piece of wood to protect the end

Camilo

Look up some pro-quality videos on YouTube under topics like "remove crank" or "replace bottom bracket" (they often begin with crank removal). That will give you an idea of how hard it needs to be whacked - pretty hard sometimes. It's often recommended that you have a helper hold the frame when you whack the crank spindle so that it is relatively stable, not twisting against whatever tube the repair stand is holding it by, or even if the bike's on the floor, just to stabilize the forces involved.

3alarmer 

...in essence, all those press fit cups on either side do is provide a fixed location for the bearings.

So in this particular case, if the BB shell has not been previously faced level on both sides, and the press fit thingies have a lip that is supposed to contact the shell (by which they gain both further support, and alignment), you might get a less perfect alignment of the bearings. If they are roller bearings, an imperfect alignment of them with each other and the shaft running slightly cattywumpus because of it, the bearings might have a slightly shorter lifespan. But I think that now some of them are not roller bearings.

In real world applications, it's usually not a big deal.

It is entirely possible, if you tap that shaft hard enough, and it's really stuck in the interior bearing collar, that you can screw up the clearance in the cartridge bearings. usually, some kind of penetrating oil applied to the shaft where it enters the bearing assembly will solve this problem. i.e. make it easier to tap the shaft through.

I think if the space is as small as you say, I would just leave it alone and not obsess about it. Worst case is you get a slightly shorter bearing life, or a creak. The creak is bad, but you can address it when it arises, if it ever does arise. Which it probably won't, but might. You never know.

3alarmer 

invalid.user

Thanks for the comments and wisdom, everyone! I appreciate everyone's feedback. As promised, here is a photo of the bottom bracket with the barely visible gap, full of grease:

i.imgur(DOT)com/0qS4fcM.jpg (replace (DOT) with .)

After reading all the comments, I'm leaning towards leaving it in there and keeping an eye on it (if the gap gets any bigger, any noise, etc.). Is that a logical conclusion? Thanks again.

Iride01 

The pic...

Troul 

send it.

invalid.user

Thank you!

invalid.user

So, yet again, I tried to remove the crankset and failed just like all the other times. I can take off the non drive side crank arm just fine, but the drive side part of the crank attached to the spindle does not budge. I was hitting the spindle so hard with the rubber mallet, that I was concerned the carbon fiber frame was going to break. I started thinking if there was any way to press the bottom bracket without having access to the other side for bracing, and a thought occurred to me. I still had the old bottom bracket. I placed one side of the old bottom bracket around the protruding part of the spindle, where the non drive side crank arm would attach, which meant that this bottom bracket was now directly touching the installed one that wasnt pressed in all the way. I hit the old bottom bracket with the rubber mallet a few times, and it worked! The bottom bracket was now pressed in completely all the way with no gap! I'm so glad that worked!

TL;DR solution for anyone else having this problem in the future: Place your old bottom bracket around the exposed part of the spindle and insert it so that it is touching the installed bottom bracket. Hit the old bottom bracket with a rubber mallet a few times, and it'll push in the installed bottom bracket all the way in!

Troul 

can you post a picture of the process?

invalid.user

I was beating myself up for not taking photos, but was hoping my description was good enough. Unfortunately, did not take any photos, but if I take that non drive side crank arm off and remember to, I will definitely post a photo. The bottom bracket itself is now FULLY pressed in with no gap, so I can finally stop obsessing over it and worrying about the dirt that would’ve gotten in there.