cnighbor1
05-16-2020, 10:51 AM
May 16, 2020
INSTALLING BOTTOM BRACKETS
I posted this video to a few friends including Grant Petersen and Robert Freeman. Both in the bicycle sales business including repair. Here is their comment on installing bottom brackets.
Robert freeman
A Couple of rookie moves there:
*
1.* He should have had the BB at the bottom when tapping, not up at chest high,* so the cutting oil and chips don't go into the down tube.** And he should have washed it out with solvent, not just wipe with a cloth.
2.* Should have put the grease in the BB shell instead of on the cups, so that you don't just wipe it off the threads on the way in.* If it is in the shell, it will have grease on all the threads.*
*
47 years and counting, putting bottom brackets in.*
Robert D Freeman
North Bend WA
-----Original Message-----
From: Charles Nighbor
To: Robert Freeman
Sent: Fri, May 15, 2020 4:29 pm
Subject: View video
https://www.rivbike.com/collections/bottom-brackets
From Grant Petersen
What to grease and when to grease is not something we haven't thought about. In other words, we've thought about it.
In theory, yes, threading a greased cup into a raw shell will force the grease outward. A few points to consider, though, and I say all this non-defensively, more just "explaining the thinking."
• if the shell threads effectively strip the cup threads of grease during insertion, then greasing then a raw cup would probably do the same to the greased shell threads.
In the first case, you'd have a ring of great on the outside of the shell around the cup, and the volume would be near equal to the amount you put on the cup threads. That doesn't happen. There's a small bit, which means the rest of it is in the threads, and there's so little space for grease, that the small bit remaining is probably enuf.
In the second case, the raw cup would invisibly push the grease past the innermost threads. It probably happens a little, but not enough to worry about.
The argument, as I see it, isn't where to put the grease, but whether to grease at all. Phil says loctite. Should you grease the threads and then apply the blue loctite?
Shimano and others supply their own threadlocks already on the fixed cup, at least. It always feels like
Robert Freeman-- not entirely superb, to neuter that with grease, but we do it.
I think the best stuff for bb shells, steer tube threads, bottle bolts, rack bosses, and other threaded things that need lube to go* in and protect the interface, but you don't want them to loosen...is a mix of beeswax and either pine tar or lanolin or both. It's slipper enough, is anti-vibration, and coats the threads/prevents bonding and rust. I do that on my bikes half the time, not all the time. I do it when I have it (and these days I usually do) and when I believe in my heart that grease is better for bearings than it is for threads.
I think the stuff you use on threads is "of minor import," and mechanical skill trumps (ugh) all. :)
Grant
sent from my iPhone
Grant Petersen
Robert Freeman
Good arguments.** Here's the difference.* When you put the grease in the shell instead of on the cups, you won't remove it all when putting the cups in. They can't be that tight, or they won't go in at all.** There has to be some amount of clearance.* So all the threads will have some grease on them.* In addition, since you are pushing the grease ahead of your part, you are thoroughly coating the innermost threads, whereas if you only have it on the cups, and you are scraping a good deal of it off on the way in, the innermost threads may not get much at all.* I don't look at the grease so much as lubricant for the surfaces.* Obviously since there is clearance, it doesn't really need that.* But as rust prevention.** A rusted-in BB is the devil to remove.* A rust molecule FE2O3, is bigger than the iron molecule it came from, which is why it seizes in place. ** I also coat the part of the shell between the threaded parts, so that when water gets in there, you don't have rust forming there.** I know that water getting into a BB shell is a foreign idea for you Californiators, but here in the NW it is almost guaranteed.**
Phil Wood recommends loctite because you aren't bottoming out anything against the shell to keep it tight, so it does what loctite is designed to do, keep threads from unthreading.* And their rings being only 3/8" or so wide, don't need much lube.* They are stainless, so should not be able to rust in place.** I still coat the inner part of the shell with grease, being careful not to get it on the part where the rings will be.* I grease the cartridge/ring interface too.*
Those Shimano and other cartridge BB's with cups that have loctite on them, even though they bottom out on the right side, they can squeak.* The loctite helps against that.* But like you I grease them anyway.* It won't prevent the loctite from doing its job in the case, preventing squeaks.* I think probably in the factories, when they put one of those BBs in, they don't use grease at all, so the loctite is necessary. ** It's good that you also grease the inside of the adjustable cup where it fits on the cartridge, as that is another area that often squeaks.**
Next subject - Are you a taper greaser or a dry-installer?* I go with Jobst on that, and have long before I ever heard of Jobst.*
Robert D Freeman
North Bend WA
INSTALLING BOTTOM BRACKETS
I posted this video to a few friends including Grant Petersen and Robert Freeman. Both in the bicycle sales business including repair. Here is their comment on installing bottom brackets.
Robert freeman
A Couple of rookie moves there:
*
1.* He should have had the BB at the bottom when tapping, not up at chest high,* so the cutting oil and chips don't go into the down tube.** And he should have washed it out with solvent, not just wipe with a cloth.
2.* Should have put the grease in the BB shell instead of on the cups, so that you don't just wipe it off the threads on the way in.* If it is in the shell, it will have grease on all the threads.*
*
47 years and counting, putting bottom brackets in.*
Robert D Freeman
North Bend WA
-----Original Message-----
From: Charles Nighbor
To: Robert Freeman
Sent: Fri, May 15, 2020 4:29 pm
Subject: View video
https://www.rivbike.com/collections/bottom-brackets
From Grant Petersen
What to grease and when to grease is not something we haven't thought about. In other words, we've thought about it.
In theory, yes, threading a greased cup into a raw shell will force the grease outward. A few points to consider, though, and I say all this non-defensively, more just "explaining the thinking."
• if the shell threads effectively strip the cup threads of grease during insertion, then greasing then a raw cup would probably do the same to the greased shell threads.
In the first case, you'd have a ring of great on the outside of the shell around the cup, and the volume would be near equal to the amount you put on the cup threads. That doesn't happen. There's a small bit, which means the rest of it is in the threads, and there's so little space for grease, that the small bit remaining is probably enuf.
In the second case, the raw cup would invisibly push the grease past the innermost threads. It probably happens a little, but not enough to worry about.
The argument, as I see it, isn't where to put the grease, but whether to grease at all. Phil says loctite. Should you grease the threads and then apply the blue loctite?
Shimano and others supply their own threadlocks already on the fixed cup, at least. It always feels like
Robert Freeman-- not entirely superb, to neuter that with grease, but we do it.
I think the best stuff for bb shells, steer tube threads, bottle bolts, rack bosses, and other threaded things that need lube to go* in and protect the interface, but you don't want them to loosen...is a mix of beeswax and either pine tar or lanolin or both. It's slipper enough, is anti-vibration, and coats the threads/prevents bonding and rust. I do that on my bikes half the time, not all the time. I do it when I have it (and these days I usually do) and when I believe in my heart that grease is better for bearings than it is for threads.
I think the stuff you use on threads is "of minor import," and mechanical skill trumps (ugh) all. :)
Grant
sent from my iPhone
Grant Petersen
Robert Freeman
Good arguments.** Here's the difference.* When you put the grease in the shell instead of on the cups, you won't remove it all when putting the cups in. They can't be that tight, or they won't go in at all.** There has to be some amount of clearance.* So all the threads will have some grease on them.* In addition, since you are pushing the grease ahead of your part, you are thoroughly coating the innermost threads, whereas if you only have it on the cups, and you are scraping a good deal of it off on the way in, the innermost threads may not get much at all.* I don't look at the grease so much as lubricant for the surfaces.* Obviously since there is clearance, it doesn't really need that.* But as rust prevention.** A rusted-in BB is the devil to remove.* A rust molecule FE2O3, is bigger than the iron molecule it came from, which is why it seizes in place. ** I also coat the part of the shell between the threaded parts, so that when water gets in there, you don't have rust forming there.** I know that water getting into a BB shell is a foreign idea for you Californiators, but here in the NW it is almost guaranteed.**
Phil Wood recommends loctite because you aren't bottoming out anything against the shell to keep it tight, so it does what loctite is designed to do, keep threads from unthreading.* And their rings being only 3/8" or so wide, don't need much lube.* They are stainless, so should not be able to rust in place.** I still coat the inner part of the shell with grease, being careful not to get it on the part where the rings will be.* I grease the cartridge/ring interface too.*
Those Shimano and other cartridge BB's with cups that have loctite on them, even though they bottom out on the right side, they can squeak.* The loctite helps against that.* But like you I grease them anyway.* It won't prevent the loctite from doing its job in the case, preventing squeaks.* I think probably in the factories, when they put one of those BBs in, they don't use grease at all, so the loctite is necessary. ** It's good that you also grease the inside of the adjustable cup where it fits on the cartridge, as that is another area that often squeaks.**
Next subject - Are you a taper greaser or a dry-installer?* I go with Jobst on that, and have long before I ever heard of Jobst.*
Robert D Freeman
North Bend WA