I have a relatively new Pinarello road bike with an Italian threaded bottom bracket (right hand threads on both cups - those silly Italians!) and I have had the drive side cup work itself loose a couple times - not confidence inspiring when you notice it and are on a mountain road 30 miles from home without the proper tools to reinstall a bottom bracket cup! I have always simply greased the cups and torqued them down to spec. but this doesn't seem to be working. Is there any problem with using blue Loctite on your bottom bracket cups instead of grease?
Italian Threaded BB and Loctite
- Thread starter Nanda
- Start date
Kinda curious are you running campy or shimano? I have seen campy loosen up more frequently than shimano. The Italian Shimano bb's seem to be a tad oversized, and fit really tight. Anyone else seen this or am I breathing too much fumes.
It's a Shimano Dura-ace bottom bracket.
Hmm I've built two Princes w/ DA and neither of them loosened up. You may want to try plumbers tape before the loctite. Plumbers tape is usually used to help solve creaks but it maybe worth trying now.
I will give that a try first then. Thanks.
plumbers tape would be o.k. but i would recommend anti-seize on the threads. just make sure the cup IS tight. don't crank on it but just check that it is tight.
the faword motion of the cranks will try to keep tightening the cup, so it seems to me that it just was'nt tight enough.
those silly italians are kinda smart.
new dura ace italian bb's tend to have a thicker coat of thread locker on the cups for some odd reason and that is usualy why they are more difficult install the first time. just remove most of it with a wire brush and it will go in like butter.
the faword motion of the cranks will try to keep tightening the cup, so it seems to me that it just was'nt tight enough.
those silly italians are kinda smart.
new dura ace italian bb's tend to have a thicker coat of thread locker on the cups for some odd reason and that is usualy why they are more difficult install the first time. just remove most of it with a wire brush and it will go in like butter.
Actually, that is not at all correct. It seems counter-intuative, but the rotating action of the cranks actually loosen the right handed threads on the drive side of an Italian threaded bottom bracket. Have a look at any bottom bracket with standard threads - they thread into the bottom bracket shell in the opposite direction of the rotation of the cranks, because the action naturally tightens them.
I stand by my original opinion - really silly Italians!
i might be missing something but i do not believe that the bearings cause the cup to move the opposite way. italian bb's get tight by turning the cup to the right on the drive side and on the non-drive. (with you standing on the side of it) the spindle rotates to right which cause the bearings to rotate to the right. even if they were a gear (bearings and spindle) it still would not allow the cup to loosen from motion.
if you ment regular bottom brakets as being english BB, the reason they are that way is beacause back in the day when most road frames were steel and rust was a problem the italian bb's had a tendency to cease in the frame because they became rusted and very tight. so those handy peaple at raliegh U.K. canged the dia. of the shell as well as its threading so siezing would be less likely.
if you ment regular bottom brakets as being english BB, the reason they are that way is beacause back in the day when most road frames were steel and rust was a problem the italian bb's had a tendency to cease in the frame because they became rusted and very tight. so those handy peaple at raliegh U.K. canged the dia. of the shell as well as its threading so siezing would be less likely.
No, he's right. If the cranks were turning on bushings in the BB, they may want to tighten the bottom bracket if it was a right hand thread, but bearings are turning the opposite way to the cranks and therefore tend to tighten a standard Euro BB.
Oops - Kona Dude beat me to the punch.
The inner race in a bearing, when rotating clockwise causes the bearings to rotate counter-clockwise, which in turn makes the outer race rotate counter-clockwise.
The inner race in a bearing, when rotating clockwise causes the bearings to rotate counter-clockwise, which in turn makes the outer race rotate counter-clockwise.
ok we understand and are in agreeance that each ball bearing does rotate in the opposite direction of the bb spindle, right?
but the bearings do not work as individuals they work as an unit, for arguments sake you could say they are a bushing.
i appologize what i said about if they were a gear. if they were a geared system where you have teeth in the cup and on the spindle then the english version is the better choice, but the bearings are there to reduce friction just like a bushing. so the cup will always want to remain at rest.
if the ball bearings were to also turn on an axle the english bb would also be the way to go because they do not FOLLOW the direction of the spindle. but since they do follow the direction of the spindle the cup wants to follow, so it may be at rest.
but the bearings do not work as individuals they work as an unit, for arguments sake you could say they are a bushing.
i appologize what i said about if they were a gear. if they were a geared system where you have teeth in the cup and on the spindle then the english version is the better choice, but the bearings are there to reduce friction just like a bushing. so the cup will always want to remain at rest.
if the ball bearings were to also turn on an axle the english bb would also be the way to go because they do not FOLLOW the direction of the spindle. but since they do follow the direction of the spindle the cup wants to follow, so it may be at rest.
The difference is that, unlike a bushing the individual bearings are free to rotate individually (while still being free to move around the bearing shell as a unit). The rotation of the individual bearings will create some friction with the outer race and cause it to rotate in the opposite direction.
get a nice bb, ensure there is little to no oil/grease in the bearings, lightly hold the shell and rotate the spindle you will notice that the amount of force to hold back the cup increases not decreases.
remember the bearings are not turning the spindle, the spindle is turning the bearings.
remember the bearings are not turning the spindle, the spindle is turning the bearings.
I really have nothing more to add rfemurfx.
The problem of loosening drive side Italian BB cups is well documented. You don't have to believe it if you don't want!
The problem of loosening drive side Italian BB cups is well documented. You don't have to believe it if you don't want!
Just for rfemurfx:
Some documents listing problems with Italian bottom bracket drive side cups are listed below - sources are Velonews, Grandmaster mechanic Sheldon Brown and the rec.bicycles FAQ - I am sure a search engine would turn up a whole bunch more if you care to look...
http://www.velonews.com/HyperNews/get/archives/archive80/13/5.html
http://www.sheldonbrown.org/gloss_bo-z.html (scroll down to "bottom bracket")
http://www.faqs.org/faqs/bicycles-faq/part4/index.html (try finding the word "Italian")
Some documents listing problems with Italian bottom bracket drive side cups are listed below - sources are Velonews, Grandmaster mechanic Sheldon Brown and the rec.bicycles FAQ - I am sure a search engine would turn up a whole bunch more if you care to look...
http://www.velonews.com/HyperNews/get/archives/archive80/13/5.html
http://www.sheldonbrown.org/gloss_bo-z.html (scroll down to "bottom bracket")
http://www.faqs.org/faqs/bicycles-faq/part4/index.html (try finding the word "Italian")
http://www.faqs.org/faqs/bicycles-faq/part4/index.html
at this site you gave i found some answers.
i am not purposely trying to be rude or "right" im just trying to understand. i have studied physics and mechanical principals and i am having trouble understanding. the other sites you gave me i did not like only because they seemed single sided with no real explanation. granted this one does not give formulas but at least is coming from a stanford alumni.
Subject: 8f.18 Bottom Bracket Bearing adjustment
From: Jobst Brandt <jobst.brandt@stanfordalumni.org>
Date: Wed, 03 Jan 2001 16:50:20 PST
A left hand thread is preferred on the right hand cup because it has a
tendency to unscrew if not rigidly tight. The propensity to rotate is
small, and will, depending on pedaling, sometimes unscrew a left hand
thread that was not tight so that a left hand thread alone will not
prevent loosening. The right hand cup should be made as tight as
practical and not be removed during regular maintenance. Because cups
seldom fail, right hand cups seldom require removal.
i do like this conversation because you have to admit it does make you think.
at this site you gave i found some answers.
i am not purposely trying to be rude or "right" im just trying to understand. i have studied physics and mechanical principals and i am having trouble understanding. the other sites you gave me i did not like only because they seemed single sided with no real explanation. granted this one does not give formulas but at least is coming from a stanford alumni.
Subject: 8f.18 Bottom Bracket Bearing adjustment
From: Jobst Brandt <jobst.brandt@stanfordalumni.org>
Date: Wed, 03 Jan 2001 16:50:20 PST
A left hand thread is preferred on the right hand cup because it has a
tendency to unscrew if not rigidly tight. The propensity to rotate is
small, and will, depending on pedaling, sometimes unscrew a left hand
thread that was not tight so that a left hand thread alone will not
prevent loosening. The right hand cup should be made as tight as
practical and not be removed during regular maintenance. Because cups
seldom fail, right hand cups seldom require removal.
i do like this conversation because you have to admit it does make you think.
The problem with rotating a bottom bracket in your hand is that you haven't put a load on the bearings. Holding the shell and rotating the spindle will, of course, make the shell feel like it wants to spin in the same direction - the "bulk" friction between the bearing, the lubricant/packing and the race far overcome any load induced rotational force that would be transfered to the outer race by the spinning bearing (the net load on the bearing is only a couple grams - the weight of the spindle). Try the same experiment with a 200lb load on the axle and see what happens...
i've been trying to find some answers with some kind of legitemate(sp?) explanation. i've found that it is not easy.
we both agree that the bearings spin in opposite direction to the spindle. do we also agree that the bearings as they spin follow the spindle as it rotates?
p.s. if you do not want to reply to this anymore just say so. stuff like this bothers me. specialy when i cant find a logical explanation. it bothers me more when the only answer i find is "the bearings turn opposite to the spindle and thats that."
thats not the only thing that happens in there you know. anyways sorry if i was a jerk.
we both agree that the bearings spin in opposite direction to the spindle. do we also agree that the bearings as they spin follow the spindle as it rotates?
p.s. if you do not want to reply to this anymore just say so. stuff like this bothers me. specialy when i cant find a logical explanation. it bothers me more when the only answer i find is "the bearings turn opposite to the spindle and thats that."
thats not the only thing that happens in there you know. anyways sorry if i was a jerk.
I just followed all of this and also agree that the bearings spin in opposite directions. They also follow the spindle as they rotate.
However, their rotation in that direction makes then push the bottom bracket in such a way that a right hand thread on the drive side would want to loosen (turn counterclockwise)...
The same applies for pedals. Right hand pedals are standard thread, left pedals are left thread, because the bearings make the axle actually want to tighten in this configuration. Try riding a unicycle backwards, the pedals will almost surely unthread.
There is no doubt that the bearings rotate in the opposite direction of the spindle.
The bearings rotate around the spindle (in the same direction the spindle turns) because of friction created from the contact between the loaded bearing and both inner and outer races. The turning inner race will spin the bearing on it's own axis, but since the outer race is (supposedly!) immobile, the friction will cause the edge of the bearing to be "dragged along" with the spindle. However, at the same time the inner race pushes the loaded bearing forward, the friction created on the opposite side of the rotating bearing will apply a force in the opposite direction against the outer race (subject to the different contact angle, etc.) making it want to rotate backward.
P.S. If it helps, I appreciate your curiosity - I've studied a bit of physics and mechanical principles myself. In fact, I get paid pretty good because of it these days! --> Nanda = Jeff Dyck - B.A.Sc (Engineering - U of Waterloo '94), M.A.Sc (Engineering - U of Waterloo '98)
it seems to me now that this is the same argument that has been going on ever since the change to english bbs.
so the question remains (after some investigating), is the force of the bearings strong enough to overcome the seals and grease? i have not been able to figure out a way to prove or dis-prove this, but the concensus is definately against me!
oh yeah, loctite on the fixed cup (blue 242) is a very good way to keep any cup in place. an other way if you rather not use loctite, make sure the bb shell is faced and tighten.
ps. if you care to know, i dont feel a piece of paper speaks of ones knowledge.
so the question remains (after some investigating), is the force of the bearings strong enough to overcome the seals and grease? i have not been able to figure out a way to prove or dis-prove this, but the concensus is definately against me!
oh yeah, loctite on the fixed cup (blue 242) is a very good way to keep any cup in place. an other way if you rather not use loctite, make sure the bb shell is faced and tighten.
ps. if you care to know, i dont feel a piece of paper speaks of ones knowledge.
rfemurfx, the effect which you are not seeing is called precession.
Try this: Make a fist of your left hand. Rest a pen fairly snugly between your index finger and palm. Now, make a sweeping circle with the other end of the pen. Note the direction in which the pen turns.
Try this: Make a fist of your left hand. Rest a pen fairly snugly between your index finger and palm. Now, make a sweeping circle with the other end of the pen. Note the direction in which the pen turns.
