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BB coming loose?!

canadmos

Cake Tease
May 29, 2011
14,145
11,459
Canaderp
I got a new bottom bracket; bsa30 or whatever for Race Face Cinch cranks, if it matters.

Last week looking for a creak on my bike, I discovered the drive side bb cup was ever so slightly loose.

Took it off, cleaned, greased and put it back on. Gave her an extra uggadugga, as @roflbox would recommend.

Nope, the drive side cup came loose again tonight. I thought it was the preload thing on the cranks, but noticed that the ISCG tabs that are splined behind the cup are also loose. The thing got so tight while I was trying to nurse it out of the forest that I had to start walking.

This is the first time a BB has ever come loose on me. What would cause that? Am I just not giving it enough beans tightening it? It seemed plenty tight to me. And while pedaling, aren't you spinning the bearing in the tightening direction anyways??

????
 

Katz

Monkey
Jun 8, 2012
371
786
Arizona
Try pedaling backwards? Work on your fakie skills!

How does the bearing feel? Any chance it binds up a bit under heavy pedaling load and causes the BB cup to start backing out?
 

canadmos

Cake Tease
May 29, 2011
14,145
11,459
Canaderp
Try pedaling backwards? Work on your fakie skills!

How does the bearing feel? Any chance it binds up a bit under heavy pedaling load and causes the BB cup to start backing out?
I did notice that the drive side bearing does feel ever so slightly not as smooth as the other one. Tried pedaling backwards a bunch last night, but it didn't help get the cup back in at all. :(

I cranked that sucker down this morning and it didn't budge today.

I still need to find this creak, so will take a closer look at the bearing when I grease the pivots. Maybe I got a bunk one?
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
18,161
2,307
01776
I'd consider chucking a little loctite on there. I have an older (older like tapered) bb that came from the factory with I believe red loctite. I'm guessing it's not true red "permanent" loctite, but it probably serves to avoid the issue you're facing. I'd think a very light duty threadlocker might help this situation, but the threads are so fine on a BSA BB and many of the BB cups out there are pretty shitty when it comes to tool engagement, so just a dab'll do ya.
 

4xBoy

Turbo Monkey
Jun 20, 2006
5,697
812
Minneapolis
I have a frame that likes to loosen up the BB almost want to threadloc it but the 30mm bearings fail so often it would probably be toast in a year.
 

Westy

the teste
Nov 22, 2002
45,210
10,825
Sleazattle
you'd use 243 in that case though, right? (assuming you also grease the bb)
Considering the large diameter I would probably use bearing retainer or 222 and would only apply to the last few threads.

I have also found that using loctite with lubed threads still works for a light bond. The loctite doesn't adhere to the metal, but fills gaps helping to hold things tight.
 

Westy

the teste
Nov 22, 2002
45,210
10,825
Sleazattle
I've had good success using Teflon tape and grease in similar applications. "Locks" without locking.
I really want to see how high viscosity damping grease works with fasteners, theoretically it could help where a fastener comes loose from vibration. It is the stuff the use on things like volume knobs to give a cheap lightweight plastic part a weighty feel.

 

Adventurous

Starshine Bro
Mar 19, 2014
7,231
4,447
Crawlorado
I really want to see how high viscosity damping grease works with fasteners, theoretically it could help where a fastener comes loose from vibration. It is the stuff the use on things like volume knobs to give a cheap lightweight plastic part a weighty feel.

Huh, neat, I wasn't familiar with damping grease. Seems like a fantastic product for a very specific purpose.

Thanks for the heads up.
 

Westy

the teste
Nov 22, 2002
45,210
10,825
Sleazattle
Huh, neat, I wasn't familiar with damping grease. Seems like a fantastic product for a very specific purpose.

Thanks for the heads up.
I am going to pull dampers out of forks, lube them with that stuff and sell them to weight weenies.

I am assuming at some speed/force the stuff just breaks down, if not on some mechanical level but from temp rise.
 

Adventurous

Starshine Bro
Mar 19, 2014
7,231
4,447
Crawlorado
I am going to pull dampers out of forks, lube them with that stuff and sell them to weight weenies.

I am assuming at some speed/force the stuff just breaks down, if not on some mechanical level but from temp rise.
You should also replace the oil in the damper with a Newtonian fluid while you are at it. Let the digressive nature of your damping grease be offset by the now rigid high speed compression!
 

Westy

the teste
Nov 22, 2002
45,210
10,825
Sleazattle
Back to the question at hand. What is acting as the spacer? BBs usually use some kind of plastic. Having a softer material helps to pre-load the threads and maintain torque. A hard smooth material like aluminum can make it more likely to come loose. Lightly peening the surfaces of the spacer with a punch can give the clamping surfaces something to bite into.
 

Westy

the teste
Nov 22, 2002
45,210
10,825
Sleazattle
You should also replace the oil in the damper with a Newtonian fluid while you are at it. Let the digressive nature of your damping grease be offset by the now rigid high speed compression!

If I use heavy cream, can I ride and make butter at the same time?
 

Jm_

sled dog's bollocks
Jan 14, 2002
13,536
5,174
AK
I had a frame back in the day that I chased the threads backwards (wrong side). I went for broke and did the other side, installed my BB with loctite, never had any problems...I never told anyone this.
 

StiHacka

Compensating for something
I really want to see how high viscosity damping grease works with fasteners, theoretically it could help where a fastener comes loose from vibration. It is the stuff the use on things like volume knobs to give a cheap lightweight plastic part a weighty feel.

I have a tube of damping grease and use it to silence a rattling two piece cassette. Works for a while but getting that fucker out of the tube is not easy.
 

Westy

the teste
Nov 22, 2002
45,210
10,825
Sleazattle
I just ordered a jar for that reason.
I had a frame back in the day that I chased the threads backwards (wrong side). I went for broke and did the other side, installed my BB with loctite, never had any problems...I never told anyone this.

Would be a fun surprise to discover when buying a used bike.
 

HardtailHack

used an iron once
Jan 20, 2009
3,224
957
I really want to see how high viscosity damping grease works with fasteners, theoretically it could help where a fastener comes loose from vibration. It is the stuff the use on things like volume knobs to give a cheap lightweight plastic part a weighty feel.

Not quite grease but this polymer can be cycled(?) up to five times-
 

canadmos

Cake Tease
May 29, 2011
14,145
11,459
Canaderp
2 ugga duggas
Two rides in after adding an extra ugga dugga and so far so good.

But I have to take the crank off for like the 5th time in two weeks, to take out the lower pivot bolts. Dammit I so wish they were Shimano cranks.

Going to look at the driveside bearing a little closer and send a note to Cane Creek if it feels rough.
 

canadmos

Cake Tease
May 29, 2011
14,145
11,459
Canaderp
Back to the question at hand. What is acting as the spacer? BBs usually use some kind of plastic. Having a softer material helps to pre-load the threads and maintain torque. A hard smooth material like aluminum can make it more likely to come loose. Lightly peening the surfaces of the spacer with a punch can give the clamping surfaces something to bite into.
On the driveside there is no spacer (I think, could be wrong from memory), but it sits up against the ISCG tab bracket thing, which is smooth aluminum.
 

Jm_

sled dog's bollocks
Jan 14, 2002
13,536
5,174
AK
But I have to take the crank off for like the 5th time in two weeks, to take out the lower pivot bolts. Dammit I so wish they were Shimano cranks.
.
I got 2 foot sections of PVC in various sizes. One section goes over the breaker bar, one section goes over the crank arm with the pedal removed. Bigger lever wins.