UN55 BBs not so good anymore?

[robc02]

Can't recommend the carbon-shelled Token type, rough bearings after one wet ride. Re-greased them and re-fitted but a couple of rides later the thing is making all sorts of noises again so will be headed for the bin!

I might have mentioned this upthread, but I managed to get several years of foul weather use out of one of these, but I did disassemble it and fill with semi-fluid grease to begin with. So all is not lost if you don't mind a bit of intervention
I was more miffed that the bearings are not a standard size, so replacements are quite expensive, and you still have the old external seals in place, so I felt it was not economical to repair.

[fastpedaller]

My apologies if this has already been stated, but with sealed BB's how is it possible to get more lubrication into the bearings without taking a risk of either 1) damaging the external seals or 2) drilling a hole in the sleeve? 2 is presumably easier with a carbon sleeve, but drilling any sleeve runs the risk of contamination to the bearings.

[bgnukem]

Brucey has previously suggested the approach of grinding an area of the sleeve until it is almost a hole, then punching a hole in the thinned material, then injecting grease through the hole and closing it with some tape or similar.

The sleeve on the Token BB just buts up against the non drive side bearing and the cup fits loosely around the bearing and sleeve, so the join on the non-drive side would not be grease-tight if using a semi-fluid grease and grease inside the sleeve would not necessarily run into the bearing but could bypass it altogether.

Presumably it would also be necessary to remove the internal shields from the bearings if filling the shell with grease, but how does one access the drive side bearing when the cup on that side can't be removed from the shell??

[bgnukem]

Token type BB has extra seals which in practice can mean that there is more scope for the thing to make funny noises. The seals are not that good despite there being two sets of them.

cheers

I'm getting a clicking noise once per pedal revolution. Initially thought it was a badly-fitting LH crank or loose LH cup so took it off, checked the cup (was tight) and applied a very light smear of grease to the axle taper and refitted the crank. Was quiet for a while then started clicking again - crank still tight enough, and towards the end of Sunday's ride I was getting two clicks each rev.

I suspect the bearings might have had it!

[Brucey]

clicking? -always check the pedals and chainring bolts.

In the case of the chainring bolts 'making sure they are tight' is not sufficient. IME if you want to eliminate the chainring bolts from enquiries they should removed, the chainring interfaces cleaned, and the bolts regreased (on the threads only) before being reassembled and properly retightened (pretty tight).

Apologies if this is obvious but if you can make the cranks click by leaning on the pedals but not pedalling, you should be able to reproduce the noise when the bike is stationary, eg by leaning on both pedals at once. If you

a) lean on the cranks directly (not the pedals) or
b) do the same test with the chainrings off

and either results in silence instead of noises, you have just found your culprit.

If you can cause the noises to disappear by standing on the pedals (instead of sitting in the saddle) it might be the saddle or the seat pin.

Similarly if you can make the noises go away by holding the bars just either side of the stem instead of further out, it is probably the handlebars/stem.

If the click is really a clunk (a movement which you can feel twice per pedal rev) then it is probably something to do with the BB assy.

cheers

[robc02]

Brucey has previously suggested the approach of grinding an area of the sleeve until it is almost a hole, then punching a hole in the thinned material, then injecting grease through the hole and closing it with some tape or similar.

The sleeve on the Token BB just buts up against the non drive side bearing and the cup fits loosely around the bearing and sleeve, so the join on the non-drive side would not be grease-tight if using a semi-fluid grease and grease inside the sleeve would not necessarily run into the bearing but could bypass it altogether.

Presumably it would also be necessary to remove the internal shields from the bearings if filling the shell with grease, but how does one access the drive side bearing when the cup on that side can't be removed from the shell??

The Penrite Semi Fluid Grease I used stayed in place for a good four or five years, so the join between sleeve and cup - at least on my sample - was good enough to keep most, if not all, of the grease inside. I think I took it apart to check it once during that time (while I was doing general maintenance to a rusty frame - not because anything seemed wrong with the BB), and all was well. In fact a tiny bit of grease began to seep past the seal towards the end so the grease must have been getting to the right place.

Yes, the inner seals of both bearings are removed. The RHS one can be tapped out - I think I supported the cup on the jaws of a vice. Anyway, with a bit of tapping and supporting/gripping it all came apart in a few minutes. I fitted another one a few months ago and this time I made sure there was some semi fluid grease in the void between bearings and outer seals.

A bit more info here:
https://forum.cyclinguk.org/viewtopic.php?f=5&t=137839&hilit=Token+bottom+bracket

[Brucey]

I fitted a cheap BB of this type ( a SunRace one actually) about seven years ago and it is slightly worn but it is also -to my surprise- still going. When I installed it I removed the inner seals and flooded the insides with SFG (much as robc02 describes) and I also installed additional external shields.

I have disassembled many BBs of this sort and perching the RH cup over vice jaws and a little tapping with a hammer is usually all that is required to get the bearing out of the RH cup so that you can deal with the seals etc. I keep meaning to make a better tool for this job; something as simple as a length of tube would do the trick, but then so would temporarily screwing the BB cup into a suitable frameset.

FWIW I am also working on a scheme that converts this type of BB to full complement bearings. If I really get my act together the bearings might even be adjustable. Depending on which breaks first - the BB or the frame it sits in- will probably determine whether this happens.

cheers

[fastpedaller]

I'm puzzled how it's possible to get the bearings out without (potentially) damaging them - unless the cup fit is VERY loose? To get inside the sleeve to remove the inner seals would also require removing the bearings off the axle - again, risk destroying it. If putting in new bearings (removing inner seals and applying lots of suitable grease) and then assembling (with suitable tubes) is possible IMHO. As for the UN55's, I can't see how the NDS bearing could be removed, as it looks like the casing/sleeve is spun over, thus preventing it (without major surgery).

[Brucey]

I'm puzzled how it's possible to get the bearings out without (potentially) damaging them - unless the cup fit is VERY loose? To get inside the sleeve to remove the inner seals would also require removing the bearings off the axle - again, risk destroying it. If putting in new bearings (removing inner seals and applying lots of suitable grease) and then assembling (with suitable tubes) is possible IMHO.

to get inside a Chin Huar (or similar) you can either remove the LH bearing or knock the RH cup off as described. The RH cup will come off either with the RH bearing in it still or not. It doesn't matter which, either way you can access the inside of the sleeve and remove inner seals and/or add more lube.

Yes it risks damage if the bearings are a tight fit but the alternative is guaranteed damage because there isn't enough grease in the unit.

As for the UN55's, I can't see how the NDS bearing could be removed, as it looks like the casing/sleeve is spun over, thus preventing it (without major surgery).

it is not required that you remove the bearing. As described previously you grind the centre sleeve of the unit and then punch through to make a lube port.

cheers

[fastpedaller]

to get inside a Chin Huar (or similar) you can either remove the LH bearing or knock the RH cup off as described. The RH cup will come off either with the RH bearing in it still or not. It doesn't matter which, either way you can access the inside of the sleeve and remove inner seals and/or add more lube.

Not being awkward or confrontational, but if the RH cup comes off leaving the bearing still on the axle, how is it possible to get inside the sleeve without somehow ( grips? ) holding the outside of a bearing or sleeve, and pushing the axle? This looks like a gamble worse than just leaving the bearings with the 30% initial grease fill!

[Brucey]

to get inside a Chin Huar (or similar) you can either remove the LH bearing or knock the RH cup off as described. The RH cup will come off either with the RH bearing in it still or not. It doesn't matter which, either way you can access the inside of the sleeve and remove inner seals and/or add more lube.

Not being awkward or confrontational, but if the RH cup comes off leaving the bearing still on the axle, how is it possible to get inside the sleeve without somehow ( grips? ) holding the outside of a bearing or sleeve, and pushing the axle? This looks like a gamble worse than just leaving the bearings with the 30% initial grease fill!

with both bearings still on the spindle, but both cups off, the sleeve just pushes sideways and you can always fill the space with grease, and usually destructively remove the inner seals etc. FWIW if you don't remove the bearings when new it only gets more difficult later on; there will always be a bit of crud under the bearing radius where it fits on the spindle and this will hamper the movement of the bearing on the spindle.

These units are so cheaply made they are basically disposable. LBS's that have fitted them expected them to last about a year (of daily use) and those which don't fit them see a steady stream of bikes needing replacements (with these fitted from new) at about that age. Remember that not only is there not enough grease, but the grease that is there has almost no weather resistance whatsoever. If your bike sees the weather, IME nothing is as bad as leaving the fate of a BB of this type to chance by not adding grease; its premature demise is basically inevitable if you do this.

cheers

[fastpedaller]

But isn't the OD of the sleeve the same as the OD of the bearings and thus not removable until one bearing (at least) is off the axle? Otherwise, I'd be able to just remove the sleeve once the LH cup is off. There would also be no preload through the outer tracks of the bearings when the cups are tightened in the frame. I'm going to have to try and get an old one to dismantle - maybe one of our 3 bike shops in town will have one in the scrap?
YES - we have 3 local bike shops, that's if you include the car spares/bike spares shop which was the only one 2 years ago. Since then we have one additional (pretty good) bike shop, and another bike shop/Cafe which is a strange place with just bikes displayed and apparently no parts. it does have a sign saying "bike repairs" - maybe they take the bikes to the real place 2 shops away whilst you have a coffee

[bgnukem]

I guess there must be an axial gap between the sleeve and bearings, when the RH cup is removed?

I can't see how you'd get the RH cup off though without passing the removal force through the RH bearing, as the bearing is presumably an interference fit on both the axle and into the cup.

As a follow up to my original issue with water ingress into a Token cartridge BB, I had previously regreased the LH bearing and reassembled the BB. After ONE rainy ride (but no floods immersing the BB) I disassembled again and once again found water in the LH bearing. The twin seals (one in the up and the bearing shield itself) seem to be pretty useless. Can't imagine they would be much use at keeping semifluid grease IN the BB shell??

These Token units cost around £30-40 so are not exactly priced as disposable units!

Oddly the much cheaper all-steel Powerpro/Sugino/various other brand names BB7420 unit has identical construction, only one set of seals (on the bearings) and has given me no problems, and no water found when re-greasing the LH bearing!

[robc02]

The twin seals (one in the up and the bearing shield itself) seem to be pretty useless. Can't imagine they would be much use at keeping semifluid grease IN the BB shell??

These Token units cost around £30-40 so are not exactly priced as disposable units!

As mentioned upthread, mine were OK. I suppose it depends how thin your grease is and how bad a fit your particular seal is. A bit of seepage is a good thing.

I have located a source of reasonably priced replacement bearings for the Token units:

[url]
https://www.airevelobearings.com/produc ... as-a-pair/[/url]

A bit more info on this thread:

https://forum.cyclinguk.org/viewtopic.php?f=5&t=137839&p=1546812&hilit=token+ISO#p1546812

[Brucey]

….I can't see how you'd get the RH cup off though without passing the removal force through the RH bearing, as the bearing is presumably an interference fit on both the axle and into the cup.....

yes that is the case but the fit is normally not that tight. The load required is sufficient to be concerned about for sure but I appear to have avoided damage in any of the units I have thus far dismantled; they have all lasted much longer than normal. Thus dismantling is very much the lesser of two possible evils here.

I find that if SFG is slowly weeping out something like this ( a hub or BB unit) past 'the seals' it is much less likely that crud will be going the other way.

cheers