Shimano wheel bearings

[Brucey]

FWIW the easiest way I know of to make 'dummy dropouts' is to weld a small stack of M10 washers together. Using this simple (and compact) tool, you can check for bad (front or rear) hub adjustment with the QR pressure on normally. One of my chums now has two stacks of four SS washers in his toolbox, because I welded them together.

In point of fact, only one 'dummy dropout' is really required, on the side with the QR lever. On the other side, you can use an M6 nut (a la Colin) or sometimes nothing at all, provided the springs are removed.

[Cyclothesist]

I have an even easier approach. I use 2 chunky M10 nuts. Just slide 1 over each end of the axle. They abutt against the locknut and are deeper than the protruding axle ends so providing a good drop out substitute for checking bearing adjustment with the QR firmly clamping on the M10 nuts.
I got the nuts in a centre isle pack of various sizes at a discount supermarket.
It is inferior to Brucey's welded stack of M5 washers on the left which compresses the axle end rather than the locknut allowing you to adjust the left cone with the axle under compression.

[SprokenBroke]

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 recently dismantled, cleaned and re-greased a front axle. The grease was so infiltrated with dirt that it was black. I'm not sure where the contamination could come from? Surely in that case I'm getting rid of contamination? Even if there's no dirt what about steel that has worn off and is mixed with the grease?

[SprokenBroke]

At what point would you replace bearings? I recently serviced a front wheel hub and the bearings on one side were shiny but dull on the other. I reused them because I didn't have any on hand and I wanted to get the hub back together.

Is it worth using good bearings in a hub of unknown quality? I'm thinking about the difference between Shimano bearings and the Weldtite ones which are apparently case hardened. The hub in question is unbranded and is on a Trek bike that was probably about £500 new.

[hamster]

I always buy bearings from my local trading estate bearing factor - you can get good quality ones for a couple of pounds, so yes it's worth it even in cheap hubs if you buy smart.

[Brucey]

the weldtite balls are good because they are cheap and readily available. However, their biggest flaw is that they are not the same size as one another and this can really show.

With good quality bearings, they can/will run rough if lower quality balls are installed. In extremis, only the three largest balls will bear any load. Many years ago, I fitted shiny new balls into my campagnolo pedals. I was surprised to discover that they ran a lot smoother with the old discoloured balls fitted.
Obviously this matters a bit less with cheaper hubs, but once used, the bearing surfaces tend to wear such that the races become slightly rounder, making better balls more likely to be worthwhile.

So sometimes it is very good policy to re-use good balls even if they are suspected of being damaged eg the balls now have a discoloured surface finish

[Keezx]

CUT
Is it worth using good bearings in a hub of unknown quality? I'm thinking about the difference between Shimano bearings and the Weldtite ones which are apparently case hardened. The hub in question is unbranded and is on a Trek bike that was probably about £500 new.

Good quality bearing balls ( grade 25 or even better 10) will extend the life of ANY bearing

[Brucey]

......Good quality bearing balls ( grade 25 or even better 10) will extend the life of ANY bearing

yes, but I would still prioritise good lubrication and good adjustment over ball quality.

[AndyB1]

I have just added lube and adjusted a couple of front wheels using the advice in 531colin’s post on page 1 (except that I left the seals undisturbed).

With the rim braked hub his instructions worked fine but on the Shimano disc braked hub (HB-M525A) I could only access the LH cone and lock nut after loosening the RH ones. This was because of the disc mount. So adjustment had to be made to the RH cone and lock nut (after checking the LH ones were locked tight).
Which is the wrong way around.

Or am I missing something?

[531colin]

Long time since I did this job, or thought about it.
My recollection is that if the right hand cone isn’t tightly locked off, then precession will wind the cone inwards and eventually destroy the bearing by running it much too tight.
So as long as the right hand cone is tightly locked off when you’ve finished, I would adjust whichever side is convenient.
(I imagine this thread pre-dates disc brakes being common on bicycles!)

[Brucey]

........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.

Any hub with an Al shell (no matter how cheap) can (without great difficulty) be converted to use nice smooth cartridge bearings.

[AndyB1]

Long time since I did this job, or thought about it.
My recollection is that if the right hand cone isn’t tightly locked off, then precession will wind the cone inwards and eventually destroy the bearing by running it much too tight.
So as long as the right hand cone is tightly locked off when you’ve finished, I would adjust whichever side is convenient.
(I imagine this thread pre-dates disc brakes being common on bicycles!)

Thanks Colin.
The thread originated in 2020!
Yes, locking the RH cone tight is important. But the only way I could have made final adjustments from the LHS would have been to remove the disc in order to get a spanner onto the cone……or is there a special cranked 13mm cone spanner for this job?

[Brucey]

....... on the Shimano disc braked hub (HB-M525A) I could only access the LH cone and lock nut after loosening the RH ones. This was because of the disc mount......

FWIW if you use a cranked cone wrench, you ought to be able to access the LH cone normally; this is highly desirable because the RH cone/locknut might well be (thread-) locked onto the axle as a guard against precession.

[Brucey]

....…or is there a special cranked 13mm cone spanner for this job?

I have never seen one, but I have designed one, if that makes sense.

[AndyB1]

‘Cranked’ is probably the wrong term (my mistake) - the spanner needs to be ‘offset’ so it can fit on the cone and avoid the disc mount in order to operate on the LHS.
How do others adjust Shimano hubs that take discs?

As Brucey has said, a ‘special’ tool may be needed.