Locktite, carbon frame and headset bearing
Discussion
Is there a specific locktite I can use to remove play in head set bearings? Specifically for a carbon frame and the metal bearing. 608 seems like it has been used by cyclists but I cant find any
My top bearing has movement, a shim will stop this, in my case its a piece of thin cardboard wedged between the frame and the bearing.
Trying to find an alternate IS42 bearing but tested a couple now and both have movement so suspect the frame is the problem. May have ovalised if thats even a word.
My top bearing has movement, a shim will stop this, in my case its a piece of thin cardboard wedged between the frame and the bearing.
Trying to find an alternate IS42 bearing but tested a couple now and both have movement so suspect the frame is the problem. May have ovalised if thats even a word.
Loctite is primarily suited to threaded applications, mainly as it’s an anaerobic retaining compound, I.e it cures in the absence of air.
Bearing retention isn’t suitable for Loctite to work properly and it’s use will at best, be a sticking plaster to an underlying issue.
If the hole in the frame has become oval, Loctite will fill the gap, but won’t cure and even if it did, it wouldn’t be sufficiently strong or durable enough to withstand the forces going through the bearing.
The only solution would be to bore the hole oversize to remove the ovality and fit an oversize bearing to recover the correct retention method.
(Opinion based on more than 30 years experience in engineering using such products in engine and transmission design...
)
Bearing retention isn’t suitable for Loctite to work properly and it’s use will at best, be a sticking plaster to an underlying issue.
If the hole in the frame has become oval, Loctite will fill the gap, but won’t cure and even if it did, it wouldn’t be sufficiently strong or durable enough to withstand the forces going through the bearing.
The only solution would be to bore the hole oversize to remove the ovality and fit an oversize bearing to recover the correct retention method.
(Opinion based on more than 30 years experience in engineering using such products in engine and transmission design...
)wobert said:
Loctite is primarily suited to threaded applications, mainly as it’s an anaerobic retaining compound, I.e it cures in the absence of air.
Bearing retention isn’t suitable for Loctite to work properly and it’s use will at best, be a sticking plaster to an underlying issue.
If the hole in the frame has become oval, Loctite will fill the gap, but won’t cure and even if it did, it wouldn’t be sufficiently strong or durable enough to withstand the forces going through the bearing.
The only solution would be to bore the hole oversize to remove the ovality and fit an oversize bearing to recover the correct retention method.
(Opinion based on more than 30 years experience in engineering using such products in engine and transmission design... )
Yeah, ive used loctite for a while now, but they do offer retaining compounds that supposedly work in this sort of applicationBearing retention isn’t suitable for Loctite to work properly and it’s use will at best, be a sticking plaster to an underlying issue.
If the hole in the frame has become oval, Loctite will fill the gap, but won’t cure and even if it did, it wouldn’t be sufficiently strong or durable enough to withstand the forces going through the bearing.
The only solution would be to bore the hole oversize to remove the ovality and fit an oversize bearing to recover the correct retention method.
(Opinion based on more than 30 years experience in engineering using such products in engine and transmission design...
)Other option is to leave the shim ive put in place to prevent movement while I try warranty it, if I can warranty it for that matter
If you really need to use it, It’s the green Loctite you want ( 270 I think ), not the blue one ( 243). However, are you sure you’ve pre tensioned the headset properly? and are you sure the top cap isn’t bottoming out on the top of the steerer? When you assemble the headset, you only want the split / tension ring to sit in the middle of the top bearing, don’t push it down with your hand / a tool, before you put the stem back on. If you do that, you use up all the adjustment range, before you start tightening the top cap bolt. If the top cap is bottoming out on the steerer, pop a 3mm spacer between the top of the stem and the top cap.
Maximus_Meridius101 said:
If you really need to use it, It’s the green Loctite you want ( 270 I think ), not the blue one ( 243). However, are you sure you’ve pre tensioned the headset properly? and are you sure the top cap isn’t bottoming out on the top of the steerer? When you assemble the headset, you only want the split / tension ring to sit in the middle of the top bearing, don’t push it down with your hand / a tool, before you put the stem back on. If you do that, you use up all the adjustment range, before you start tightening the top cap bolt. If the top cap is bottoming out on the steerer, pop a 3mm spacer between the top of the stem and the top cap.
Thanks both, I know not to use the blue stuffYeah, Im sure. The upper bearing is the issue
The lower bearing is a snug fit as you'd expect
The top bearing is no longer a snug fit and has about 1mm or less of play in it, looks like its ovalised, if that's a real word. But it rocks back and forth when the compression bearing is under tension and everything tight.
With a shim in place, a piece of card about the width of 2 or 3 pieces of printing paper, the bearing is then a snug fit and there is no rocking.
Ive raised this with the bike shop i bought it from but of course no response yet
If it is an integrated headset, then the bearing should sit on an angled face, your frame might just need this angled face recutting. Park do a tool for this, although I don’t know if it is suitable for carbon, but you are only cleaning it up, so should be fine.
You just need to find a shop with one...
You just need to find a shop with one...
Assuming that you don't get anywhere with the warranty then either speak to a carbon frame repair specialist like Rob Hayles or build up the worn area with epoxy - araldite - and then sand it back to the correct shape.
It's the tapered face that does the work of centering the headset bearing and for the frame to wear oval it bike must've done some miles with a lot of play in the headset - or a seized bearing. Worth making absolutely certain that nothing is bottoming-out or working loose.
It's the tapered face that does the work of centering the headset bearing and for the frame to wear oval it bike must've done some miles with a lot of play in the headset - or a seized bearing. Worth making absolutely certain that nothing is bottoming-out or working loose.
HardtopManual said:
lufbramatt said:
Loctite 641 is the medium strength bearing retaining compound. Not sure how well it would work on CF though.
Have used it for BB30 bottom bracket bearings, seems to work well.
And make sure you use the relevant activator with it, otherwise it won't cure.Have used it for BB30 bottom bracket bearings, seems to work well.
If its a big gap then 7649 or 7471 can be used
As my first post alluded, Loctite ‘whatever grade’ is a sticking plaster to the problem that the bore that retains the bearing shell is borked.
As previously stated, the retaining compound cures on the exclusion of air. If the gap to too great it won’t cure. The data sheet above states this.
The activator is to speed the cure process up, but it doesn’t cause the cure to happen, only excluding the air will do that, and if there’s a significant clearance between the shell and housing it won’t cure....
Until the method of retaining the bearing shell is returned to proper operation by reboring and fitting an oversize shell, it will never be more than a temporary fix, which will ultimately fail.
Given its part of the headset, from a safety POV, that should be the only fix imho.
As previously stated, the retaining compound cures on the exclusion of air. If the gap to too great it won’t cure. The data sheet above states this.
The activator is to speed the cure process up, but it doesn’t cause the cure to happen, only excluding the air will do that, and if there’s a significant clearance between the shell and housing it won’t cure....
Until the method of retaining the bearing shell is returned to proper operation by reboring and fitting an oversize shell, it will never be more than a temporary fix, which will ultimately fail.
Given its part of the headset, from a safety POV, that should be the only fix imho.
Edited by wobert on Wednesday 7th April 12:39
Edited by wobert on Wednesday 7th April 12:39
probably worth a go though, might work. If it doesn't then sort a more permanent fix.
I've read the same about using a wicking Loctite to fix creaky fork crowns, 2 years later my Fox crown is still silent, and it was much cheaper than trying to get hold of a new CSU for a 10 year old pair of forks.
I've read the same about using a wicking Loctite to fix creaky fork crowns, 2 years later my Fox crown is still silent, and it was much cheaper than trying to get hold of a new CSU for a 10 year old pair of forks.
wobert said:
As previously stated, the retaining compound cures on the exclusion of air. If the gap to too great it won’t cure. The data sheet above states this.
They are what as known as ‘anaerobic adhesives’. 25 ( odd ) years ago, I used to develop and make them for Unilever. Having someone Switch the bulk mixers off, before you were ready to ‘tip’ them, was something you really didn’t want to happen.Jimbo. said:
On a related note, is there any benefit to using Loctite 641 when there are no problems re headset play, creaks etc? Good garage practice? I normally use a smear of grease when dropping the bearing into the cups and never had any problems, but always happy to learn!
I don't, because it'll probably me who eventually has to try to get the thing apart again. I use a smear of grease for press-fit components and carbon paste for clamps.Headset cartridge bearings get enough grease to - hopefully - ensure they don't rust and the cups, if there are any, don't corrode.
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