Shimano wheel bearings

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mattsccm
Posts: 3623
Joined: 28 Nov 2009, 9:44pm

Shimano wheel bearings

Postby mattsccm » 28 Dec 2020, 4:35pm

I know that this has cropped up many times but a search doesn't really produce one definitive thread.
Would some kind soul be able to come up with a post detailing the correct service procedure?
I read about spacing the QRs and lock nuts etc to get correct cone adjustment etc but can't work out how to keep things locked and adjust at the same time. I seem to miss a sentence somewhere!
Another issue I have when tightening the lock nut is that that nut moves the axle in the cone no matter how clean it is. Bang goes adjustment. It has got to the point where I am steadily rebuilding wheels with cartridge bearings as they are much simpler. Consequently I have a pile of good Shimano hubs that I should really use up if I could only get the hang of getting those cones just right.
Maybe this could become a "Too good to lose"

Brucey
Posts: 42272
Joined: 4 Jan 2012, 6:25pm

Re: Shimano wheel bearings

Postby Brucey » 28 Dec 2020, 5:18pm

All you really need to know is that there should be a little free play in the bearings which just disappears when the QR is used to secure the wheel in the frame. Everything else is pretty straightforward.

The work is best done (in the absence of a special hub vice) by gripping the RH locknut in a bench vice whilst you work on the LH cone and locknut using two spanners.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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531colin
Posts: 13335
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Shimano wheel bearings

Postby 531colin » 28 Dec 2020, 5:35pm

I'm sure Brucey has posted a scheme whereby he adjusts the bearing preload with the Q/R done up on "dummy dropouts" such as big nuts/washers.
I'm too idle to change my way of working, so I still stick to adjusting the bearing pre-load so there is a tiny bit of play which just disappears when I put the wheel in the frame and do up the Q/R. (trial and error!)
Re. the cone moving when you nip up the locknut, the cure for that is to hold the cone with a cone spanner while you tighten the locknut. As I am only blessed with the regular number of hands, I hold the opposite cone locknut in the vice at the time.
My annual maintenance is.....
undo left cone and back it off a long way, remove left grease seal.
Inject fresh grease into left bearing
Pull axle through to get access to right cone
Check right cone locknut is as tight as possible
Inject fresh semi-fluid grease into right bearing
Re-assemble left seal, locknut, etc and adjust bearing as detailed above.

Semi-fluid grease is used on the right side so some oil migrates into the freewheel mechanism
the right cone if it comes loose will precess and destroy the bearings by exerting a huge preload. Do the locknut tight!
I don't remove the "old" grease, and I have XT hubs in use which are probably old enough to vote!

pwa
Posts: 13683
Joined: 2 Oct 2011, 8:55pm

Re: Shimano wheel bearings

Postby pwa » 28 Dec 2020, 5:44pm

With a cone spanner on the cone as the lock nut is tightened, I end up with the lock nut rotating in one direction while inevitably the cone rotates a little in the opposite direction to tighten against it. I can't avoid this slight movement in the cone, which takes some pressure off the bearings, so I factor it in by starting the tightening of the lock nut with the cone a tiny bit firmer against the bearings than I want it to be in the end. I know it is right when, with the lock nut fully tightened, the axle rotates freely, with the slightest hint of play. And with the wheel back in the frame / forks the free spinning is maintained.

Brucey
Posts: 42272
Joined: 4 Jan 2012, 6:25pm

Re: Shimano wheel bearings

Postby Brucey » 28 Dec 2020, 5:52pm

you don't get that movement if you hold the RH locknut in a bench vice or similar, and you can (obviously) get more precise bearing adjustment too.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

mattsccm
Posts: 3623
Joined: 28 Nov 2009, 9:44pm

Re: Shimano wheel bearings

Postby mattsccm » 28 Dec 2020, 5:56pm

But how much is that little bit of movement? :roll:
I resorted to the rh lock nut in the vice or, slightly easier, a socket on short extension in the vice.
And just why won't the cones stay tight? Bearing surfaces look fine as do the balls. Better grade of balls?
Every other project is done apart from the damn axles on the trike so I guess this is how to spend the evening.

slowster
Posts: 1816
Joined: 7 Jul 2017, 10:37am

Re: Shimano wheel bearings

Postby slowster » 28 Dec 2020, 6:08pm

I've bookmarked Brucey's various posts on setting up and adjusting Shimano hubs so that I can find and refer to them when needed. I've given the links below, and the specific one to which I think you refer is the bottom one, which I have quoted in full afterwards. I think they should be in 'Too Good To Lose', but maybe Brucey would prefer to extract from them and collate them into one post.

Touring hubs: Shimano Deore LX 670

Greasing new hubs

Really tough and reliable hub for touring?

Snapped Shimano freehub

CX Wheel build and hub advice

To Freehub Or Not Freehub, Over Tightening!

Servicing Shimano SLX M665 Freehub

Rear hub service

Brucey wrote:you can get the hub bearing adjustment spot on in less than a minute using a 'hub vice', provided the hub is a conventional cup and cone QR hub.

The hub vice uses a QR skewer (or long bolt or w.h.y.) which is tightened to normal QR tension in such a way as the load is seen by the RH locknut and the LH axle end, using a suitable spacer each end (eg out of an old derailleur pulley at the LH end) or a stack of washers. The hub axle/locknut is then held (eg using a bench vice) on the RHS.

Because the QR load is borne by the LH axle end and not the LH locknut, the LH cone and locknut are readily accessible. When you trial an adjustment, you can snug the locknut down and it'll be much as if the wheel is in a frame with the QR similarly tight.

The fastest adjustment procedure is to finger-tighten the LH cone and then back it off about 1/5th of a turn. Then tighten the locknut and check for free play. This won't be exact but it is rare that you will be more than 1/10th of a turn out. The best adjustment is a tiny bit of free play followed by a further small (1/50th of a turn say) adjustment which removes the free play.

I've posted details of the hub vice I built here before and I might be able to find the relevant thread. There is also a write-up on Sheldon Brown.https://sheldonbrown.com/cone-adjustment.html where the hub vice is referred to as a special tool.

FWIW although it is common practice I do not recommend backing cones and locknuts against one another willy-nilly. For one thing you can't back off cassette hubs this way (there is usually no access to the RH cone) and for a second, if the RH cone and locknut start to move, it can destroy the hub. The RH cone and locknut ought to be tightened fully against one another (ideally using threadlock on the RH cone threads) and then left alone. With the RH cone/locknut in a vice, you must hold the LH cone using a cone spanner when loosening or tightening the locknut. This way (provided you keep track of any backlash between the cone spanner and the cone) you can get a really precise adjustment.

FWIW if you work to a tolerance of 1/100th of a turn then the bearings will be set to an accuracy of about ten microns. This is far better than the usual accuracy you get in a cartridge bearing hub, by the time you have allowed for typical variations in the fit quality of the bearings and so forth.

BTW rebuilding freehub bodies is not work for the impatient. Normally the topmost shims come out with the balls still in position, but they don't always come out easily. A pair of (tiny , non magnetic) paddles is often the best way of lifting the shims. The amount of free play you describe is still too much really, so more adjustment is required.

cheers
Last edited by slowster on 28 Dec 2020, 6:10pm, edited 1 time in total.

mattsccm
Posts: 3623
Joined: 28 Nov 2009, 9:44pm

Re: Shimano wheel bearings

Postby mattsccm » 28 Dec 2020, 6:09pm

woohoo :D Cheers.
It's this bit I don't get.
"The hub vice uses a QR skewer (or long bolt or w.h.y.) which is tightened to normal QR tension in such a way as the load is seen by the RH locknut and the LH axle end, using a suitable spacer each end (eg out of an old derailleur pulley at the LH end) or a stack of washers. The hub axle/locknut is then held (eg using a bench vice) on the RHS.

Because the QR load is borne by the LH axle end and not the LH locknut, the LH cone and locknut are readily accessible. When you trial an adjustment, you can snug the locknut down and it'll be much as if the wheel is in a frame with the QR similarly tight"

I'll persevere. I struggle to pick out the important bits from peoples comments .

alexnharvey
Posts: 1461
Joined: 10 Jan 2014, 8:39am

Re: Shimano wheel bearings

Postby alexnharvey » 28 Dec 2020, 6:35pm

Using a quick release clamping onto large washers (e.g. M10) on the right hand side to bear against the lock nut, smaller washers on the left hand side (e.g. M5) bearing against the axle end.

It does not eliminate the slight backlash in tightening locknut and cone but it does remove almost all the other guesswork.
Sheldon brown has a picture of his hub vise setup. https://sheldonbrown.com/cone-adjustment.html
Last edited by alexnharvey on 28 Dec 2020, 6:38pm, edited 1 time in total.

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531colin
Posts: 13335
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Shimano wheel bearings

Postby 531colin » 28 Dec 2020, 6:36pm

The reason for the difference in the adjustment with the Q/R done up vs. undone is the axle compresses
Frightening, isn't it?
So, loading the axle as Brucey suggests, you can compress the axle yet still adjust the bearing preload.
I may even try it myself!

(BTW, isn't "Slowster" organised.....how do you do that?

slowster
Posts: 1816
Joined: 7 Jul 2017, 10:37am

Re: Shimano wheel bearings

Postby slowster » 28 Dec 2020, 7:43pm

531colin wrote:BTW, isn't "Slowster" organised

Thank you...erm...I think.

531colin wrote:how do you do that?

I do some tasks so infrequently that I need to read Brucey's posts or watch the relevant Park Tool video again before I start, to make sure I do it correctly. I've only bookmarked links for two subjects: various videos etc. on hydraulic brakes and Brucey's posts above on Shimano hubs.

What prompted me to do it were the consequences of doing it wrong, e.g. destruction of the bearing and worse if the RH cone precesses, and the benefits of doing it right, i.e. hubs that should last for years with minimal further maintenance and adjustment.

pwa
Posts: 13683
Joined: 2 Oct 2011, 8:55pm

Re: Shimano wheel bearings

Postby pwa » 28 Dec 2020, 7:59pm

mattsccm wrote:But how much is that little bit of movement? :roll:
.

Why not just ask without the rolling eyes? :lol:
The answer is: so slight that I am only just sure I am not imagining it. And my method works, if the definition of success is free spinning wheels with no play, and bearings that seem to last and last. I don't currently have room for a bench on which to put a vice, and as I don't have a problem with bearing adjustment I don't see a reason to make space for it.

There's more than one way to skin a rabbit. Okay, sometimes it takes two or three goes to get it perfect, but I do that job a few times a year and waste maybe two minutes a year doing it my way.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Shimano wheel bearings (in fact all cup and cone bearings in QR hubs); "Au Point" adjustment.

Postby Brucey » 28 Dec 2020, 9:02pm

thanks to slowster for being more organised than I am!

Regarding the amount of free play; when the wheel is in the hub vice it can be felt and the relationship between QR pressure and bearing free play can be determined. A good way of feeling for free play is to put one fingertip so that it is touching both some part of the axle and the adjacent dustcap, whilst wiggling the wheel rim (in a direction parallel to the axle). You should feel the slightest free play this way, and you can double check this later, too; when the wheel is in the frame the free play can be felt at the rim when the QR is half-tight, and felt to go away when the QR is fully tight.

Other observations include that in some installations there is a broad tolerance to variations in QR pressure, and in others there is no such thing; there isn't a 'one-size fits all' hub adjustment that you would use regardless of frame and brake type. Vertical dropouts together rim brakes can allow a ~50% variation in QR tension and this allows fine adjustment of bearing clearances, all without actually adjusting the cones and locknuts. However rear wheels in slotted dropouts need to be pretty tight and front wheels with disc brakes need to be tightest of all if they are not to move in service, and with these wheels you can't vary QR tension much and therefore adjust the bearing preload.

So if you are using a hub vice tool (or equivalent), it is important to use the same QR pressure as you would when that particular wheel is installed in a bike.

With a hub vice tool, it is normally used with one end clamped in a bench vice. However it can be taken out of the bench vice and remain attached to the hub (i.e. with the service QR load still applied), and this way the you can feel if the hub bearings bind, drag, or feel rough in any way.

A final comment is that if you use 'au point' bearing adjustment, should there be the slightest wear inside the hub, or reduction in QR pressure, you will feel this as free play at the rim before there is any significant damage inside the hub.

Using hub bearing clearance as a proxy for QR pressure, it is easy enough to demonstrate that 'security skewers' offer more tension (holding force) than internal cam skewers and external cam skewers offer the lowest tension of all. Furthermore that the plastic cam seatings commonly used in external cam QR skewers creep under sustained load and those skewers lose tension all by themselves.

FWIW many current shimano hubs (with oversize aluminium axles and cup and cone bearings) offer the appearance of precise bearing adjustment but this adjustment cannot be made precisely whilst allowing for the effects of QR pressure. By contrast the campagnolo (and Fulcrum, and some Miche) bearing system with the pinch bolt collar on the LHS allows precise adjustment with the wheel in situ and whilst the QR skewer tightened in the normal way, so it is potentially super-accurate. All that would be needed is for the RH hub bearing to be in a more sensible place and those hubs might be strong enough for bikes with a proper load on.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

NickJP
Posts: 323
Joined: 24 Sep 2018, 7:11pm

Re: Shimano wheel bearings

Postby NickJP » 28 Dec 2020, 10:59pm

Brucey wrote:All you really need to know is that there should be a little free play in the bearings which just disappears when the QR is used to secure the wheel in the frame. Everything else is pretty straightforward.

The work is best done (in the absence of a special hub vice) by gripping the RH locknut in a bench vice whilst you work on the LH cone and locknut using two spanners.

cheers

For making the final bearing adjustment, I have two very fat washers (about 6mm thick) that I slip over the axle ends so that the QR can be clamped down on the washers with the wheel out of the frame, to put the same compression on the axle as when the wheel is in the frame. Makes it very easy to to feel, by turning the axle, whether the adjustment is right or not.

I do prefer the system that Campagnolo use for cup and cone hub bearings (for the past 20+ years, anyway), where the split adjustment collar allows much easier fine adjustments to be made to get zero play in the bearings without having them too tight.
Last edited by NickJP on 29 Dec 2020, 1:08am, edited 2 times in total.

Brucey
Posts: 42272
Joined: 4 Jan 2012, 6:25pm

Re: Shimano wheel bearings

Postby Brucey » 28 Dec 2020, 11:10pm

NickJP wrote:Ror making the final adjustment, I have two very fat washers that I slip over the axle ends so that the QR can be clamped down on the washers with the wheel out of the frame. Makes it very easy to to feel, by turning the axle, whether the adjustment is right or not.


what you have made is effectively a very simple hub vice, but one that isn't so easily held in a bench vice, and doesn't locate on the RH locknut. If the LH end of the skewer/ axle is mounted in the right way, you can access the LH cone and locknut for adjustment whilst the QR skewer is still tight.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~