Shimano wheel bearings

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pwa
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Re: Shimano wheel bearings

Post by pwa »

Anyone reading all this, and who has little or no experience of cup and cone bearings, may be under the impression that all cup and cone hubs can be adjusted to a state of perfection. But, of course, we do encounter old and neglected hubs in a really bad state, and with those taking out all play tends to result in the axle not moving freely. The only option is to have enough play for a hub in that state to spin freely, which usually means a displeasing amount of play that affects rim brake adjustment and makes the seals sloppy. I have a skip rescue bike in the garage that is like that. It still works, but it isn't as we would normally want a hub to be. If I cared about that bike I would change the hub.

The totally shot hubs I've played around with have been cheap and nasty things, not Shimano. I always wonder, with things like that, whether the time invested is worth it. Probably not. I am never going to be satisfied with the result.
Brucey
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Re: Shimano wheel bearings

Post by Brucey »

There are such things as worn hubs of course, and the same logic may indeed not apply to those. It is perhaps as well to remind folks that the idea of good hub adjustment is that it is part of a preventative maintenance regime; much as Colin describes upthread, a few minutes annual maintenance makes the difference between a hub which will run smoothly/ last virtually indefinitely and one that won't.

As noted previously one benefit of precise hub adjustment is that should the slightest wear occur subsequently, the bearing will soon get noticeably loose, which is your 'early warning' that all is not well. By contrast bearings which are set with an appreciable preload are both more likely to suffer damage, and are more likely to be badly worn by the time they develop free play.

Bearings which are bindy when correctly adjusted are almost certainly already worn/damaged and the best you can hope for is that the rate of further deterioration will at least be slowed by whatever maintenance you do. Needless to say hub replacement is one option, but another is to renew the bearing parts inside a cup and cone hub; the cup inserts are not easy to change, but fortunately they are also usually the last parts to wear, and hubs which are given replacement cones and ball bearings can typically be given a useful life extension.

cheers
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hamster
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Re: Shimano wheel bearings

Post by hamster »

I'm glad I am not alone in using 531Colin's method - a quick inspectiion to check there's no rusting inside and then a good slurp of grease to keep things sweet. My own view is that harm and contamination is easily done by dismantling and reassembly when all that's necessary is more grease.
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531colin
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Re: Shimano wheel bearings

Post by 531colin »

hamster wrote:I'm glad I am not alone in using 531Colin's method - a quick inspectiion to check there's no rusting inside and then a good slurp of grease to keep things sweet. My own view is that harm and contamination is easily done by dismantling and reassembly when all that's necessary is more grease.

I find I need semi-fluid grease in the right bearing to keep the freewheel running sweet. I used to drill my hubs and inject grease, but eventually the freewheel runs dry if you do that.
Brucey
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Re: Shimano wheel bearings

Post by Brucey »

531colin wrote:
hamster wrote:I'm glad I am not alone in using 531Colin's method - a quick inspectiion to check there's no rusting inside and then a good slurp of grease to keep things sweet. My own view is that harm and contamination is easily done by dismantling and reassembly when all that's necessary is more grease.

I find I need semi-fluid grease in the right bearing to keep the freewheel running sweet. I used to drill my hubs and inject grease, but eventually the freewheel runs dry if you do that.


FWIW if you want to be able to add lube to the RHS of a cassette hub without disassembly, I think it should be possible to drill the RH dustcap. The idea is that the hole would be blocked in service using a ring (eg of closed cell foam) which is trapped in position by the cassette lockring.

cheers
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531colin
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Re: Shimano wheel bearings

Post by 531colin »

OK, I'm bored...I admit it.
I just can't keep warm in these current temperatures, either riding or working in the bike shed.
So I had a bit of a scout round, and found enough bits and pieces for a hub vice.

ImageIMG_5341 by 531colin, on Flickr

The axle is held firm enough to adjust the (unlocked) cone; but locking torque needs 2 spanners. (easy, as the hub (or wheel) is held.

These are the bits I found

ImageIMG_5349 by 531colin, on Flickr

An old headset/lockring spanner which happens to have a hole in it, a proper (internal cam) Q/R skewer (Shimano as it happens, other makes are available), and an M6 nut ....and a hub to play with

The right hand end of the axle goes in the hole in the spanner, the skewer goes through the axle, the M6 nut goes on the skewer so that the compression load is taken by the axle end on the left side, and by the locknut on the right side.....so that I can adjust the cone with the axle under compression from the Q/R skewer.

ImageIMG_5345 by 531colin, on Flickr
mattsccm
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Re: Shimano wheel bearings

Post by mattsccm »

:D
mattsccm
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Re: Shimano wheel bearings

Post by mattsccm »

Finally got round to it. Used Colin's version as above as I have always been suspicious of my "just enough play" when just clamping the right lock nut in a vise or socket.
Did everything up and gave the wheel a flick of my wrist and no more. Wheel was spinning a minute later which is reasonable I reckon. It does have a tyre on so that might help. Silent and absolutely no grinding or anything that might be associated with the bearings being too tight. Sweet as could be.
Dismantled the "vise" and spun the wheel in my hand. Well tried to. Absolutely solid. No way could I hold the nuts tight enough to spin that wheel.
Grrr. I guess I have "felt " this wrong and also that, despite appearances, the hub may be damaged.
The reason why I prefer cartridge bearings.
I can't abide feeler gauges either. Too subjective. :D
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simonineaston
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Re: Shimano wheel bearings

Post by simonineaston »

I've said this before, but I'll say it again - the sum total of contributions from Brucey et al, is far too good to 'waste' by simply leaving it all in the archive of a forum database... or is that indeed the perfect place for it all? Discuss.
(rides: Brompton nano & ever-changing Moultons)
Brucey
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Re: Shimano wheel bearings

Post by Brucey »

mattsccm wrote:...Dismantled the "vise" and spun the wheel in my hand. Well tried to. Absolutely solid. No way could I hold the nuts tight enough to spin that wheel.
Grrr. I guess I have "felt " this wrong ...


No kidding. The while point is that once the QR pressure is off, there should be free play in the hub bearings. There are only a few ways you can have got it that far wrong, and all of them involve some kind of assembly problem.

BTW as your experience with this hub shows, spinning the wheel may tell you very little. Your 'preferred' cartridge bearings may be fitted with unacceptably high preload levels and you would never know. If cartridge bearings are installed and lubricated properly they ought to last almost indefinitely; as it is there ae plenty of folk who claim to 'like them' who think it is 'perfectly normal' to have to change the bearings every year.... Death by natural causes...? No, they are 'murdered'....

I may be casting aspersions here but if you think 'hub maintenance' mainly involves hitting things with hammers, there is something wrong somewhere....?...

cheers
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mattsccm
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Re: Shimano wheel bearings

Post by mattsccm »

If only I could hit them.
It would be good if these hubs were wrongly assembled. I could chuck them back at the vendors as they have about 500 miles on them. Needless to say I didn't bother to check them before I rode the damn things so quite possibly they suffered from poor greasing etc from new and I have managed to damage them through poor care. Some new balls have now been inserted and jobs a good un. One or two of the old ones were less than round!
Some Shimano 475 hubs.
I dislike anything that needs subtle adjustment as it allows for error until experience comes. That's art not science! The same reason I hate through axle chain sets which rely on preloading by hand. A nice square taper can be just done up bloody tight and whilst it shouldn't be done with a 10 foot scaffold bar , its easy to do. Things with torque settings appeal as well. Couldn't stand windsurfing either. . You have to be fairly good before its fun. I could never set the points on my Minis either but could do a cylinder head with my eyes closed (I did a lot :roll: Never bought a good one)

Cartridge bearings are easy. Bang the buggers out and in. Replace for a couple of quid every couple of years when you feel a touch of play. Funnily enough I can detect a touch a movement easily but can't adjust a cone exactly. A bike isn't, to me, something that that should cost nothing to run espcially despite me being as tight as they come.


More than anything and the point of my post was that I was surprised that a wheel that felt so sweet sat in the vice with a Qr closed on it, felt so rough with no tension at all. If I hadn't spun it by hand I wonder if I would have noticed. Ah well , something to do in these dull evening, practice. Cheers for all the help.
Brucey
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Re: Shimano wheel bearings

Post by Brucey »

mattsccm wrote:...It would be good if these hubs were wrongly assembled....


to my mind they pretty well have to be, in that if they are worn or damaged so that 'just play free' = 'too tight to turn by hand' they would have to be obviously worn/damaged, to the extent that you wouldn't now be wondering what exactly is wrong with them, you would have seen it already. Other than that, the remaining possibilities involve bits being in the wrong places when the hub was reassembled (wrong position or quantity of balls, damaged seals etc) or the worst possible adjustment. Have another go.

I am critical of shimano's hub adjustment with new hubs, but then again the correct hub adjustment before the wheels are built is simply not possible; the elastic deformation of the hubshell under spoke loading throws the bearing adjustment out . Likewise if their hubs come without enough good grease inside them it is no big deal; if you don't grease them properly all you are doing is postponing 'a repair' (of the sort you are currently undertaking) which should have been another routine service. If you know what you are doing you can set up a pair of shimano hubbed wheels in a few minutes such that they will not need to be touched for another year, and then only demand another few minutes of your time to last a further year, and so on.

I think you have done something that is fairly obviously not correct, and I suggest that you have another go.

cheers
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PT1029
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Re: Shimano wheel bearings

Post by PT1029 »

Dismantled the "vise" and spun the wheel in my hand. Well tried to. Absolutely solid. No way could I hold the nuts tight enough to spin that wheel.


Did you readjust the bearing looser and recheck? Also, did you check the cone you were NOT adjusting was secure against it's lock nut - sometimes it is not, so it can alter its position regardless of what you do to the other cone. To do this on a cassette hub, you will need to loosen the LH cone a lot so the RH cone can become exposed outside the cassette body.

Sometimes with a solid axle hub I have adjusted the LH cone while the RH wheel nut is tight against the RH dropout (acting as a vice), having first checked the RH locknut/cone was tight. Spin the wheel, fine, it spins seemingly well. Take the wheel out to double check by hand, all tight and gritty.
A tight bearing can sometime spin a remarkably long time, especially if a tyre is fitted, it adds extra momentum. I'm talking of modest but not knackered hubs here.

A more subtle check is not so much the lenght it spins for, but how sudden the final stopping of the spinning is. Usually a correctly adjusted bearing stops by getting slower and slower with a small/minimal bit of a backwards spin when it finally stops*. Less so on the rear wheel (freewheel and all that), but often a back spin within the movement of the freewheel ratchet can be seen. In a tight bearing the final stopping spinning is more abrupt.

*Not to be confused with over tight pitted bearings, where the "back spin" is the wheel rocking as the squidged balls settle into their pitted holes.
Brucey
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Re: Shimano wheel bearings

Post by Brucey »

the 'old test' for nice free hub bearings was always that the valve (or rim joint in some cases) ended up settling at the bottom when the wheels were spun. IME even quite modest hubs can be made to pass this test reasonably well.

However if the bearing surfaces are beautifully smooth, overly high preload is not readily detected this way. Furthermore the bearing surfaces certainly don't stay smooth when overly preloaded. A common result is that folk who use this method and buy expensive hubs can turn into 'serial hub murderers' (for much the same reasons as some folk end up replacing cartridge bearings on a regular basis). By contrast hubs which start out with imperfect bearing surfaces will tend to have less preload should they pass this test.

If you have a six-month old shimano hub and it binds as described then it will definitely suffer from one or more of the following;

1) severe wear
2) bad assembly
3) very poor adjustment.

A simple check for the first two above is to screw the LH cone in finger tight and spin the wheel. You should soon feel if there is a big problem there or not.

cheers
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Brucey
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Re: Shimano wheel bearings

Post by Brucey »

mattsccm wrote: Funnily enough I can detect a touch a movement easily but can't adjust a cone exactly.


if what you say is true then there is absolutely no reason why you cannot set up a cup and cone hub correctly; when the adjustment is correct the hub bearings have free play in them when the QR is not fully tightened. When set correctly the QR pressure (in a standard QR hub) eliminates that free play. [With vertical dropouts and rim brakes, you can vary the QR pressure and use this to fine-tune the hub adjustment. ]


A bike isn't, to me, something that that should cost nothing to run espcially despite me being as tight as they come.


This is missing the point. If you ride around with hubs that are eating themselves it means that some (usually simple) aspect of their setup has been (needlessly) done wrongly. It is a bit like setting your brakes to rub and then saying 'it doesn't matter because I don't mind the cost of brake blocks' .

cheers
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