rebuilding XT hubs

[anern]

Hi,
I'm halfway through rebuilding my M760 rear hub and have run across a
couple of problems :
1) I can't get the bearings to run smooth with little play (new ones) -
question : is there any variation in bearing qauilty ? I was told they're
all the same nowerdays. I made sure everything is spotless. The hubs were
perfectly smooth when new.
2) I used lithium grease though the stuff that was in there before was
taslucent green on one side and grey on the other. The stuff I used was
Weldaite and opaque white in colour - does this matter ?
3) I got the axle out OK without undoing the 17mm locking bolt that requires
a 17mm cone spanner but can't adjust properly when refitting. Is there a
bodge to avoid buying a 17mm cone spanner (£5.95 - professional tool) - or
is there a tool with other useful stuff on it that includes a 17mm cone
spanner that would be more cost effective ? I'll probably only use it a few
times before the next bit of technology comes along and makes it obsolete.

Cheers,

Bruce.

 

[Pete Biggs]

anern wrote:
> Hi,
> I'm halfway through rebuilding my M760 rear hub and have run
> across a couple of problems :
> 1) I can't get the bearings to run smooth with little play (new ones)
> - question : is there any variation in bearing qauilty ? I was told
> they're all the same nowerdays.

They should know better.

> I made sure everything is spotless.
> The hubs were perfectly smooth when new.

Bearing balls do vary in quality, but you're unlikely to notice any
difference when brand new. You should use grade 100, or better still, grade
25. The lower the grade number, the more uniform in size the balls will be.

More likely is that either you haven't got the adjustment quite right, or
the cones or cones and cups are worn. Look for pits or little dimples in
them. This can happen quickly if the cones were over-tight or
under-lubricated. New hubs sometimes need adjusting before use.

See http://www.sheldonbrown.com/cone-adjustment.html

Note the trick about using two cone spanners or two locknut spanners
simultaneously for the fine tuning.

> 2) I used lithium grease though the stuff that was in there before was
> taslucent green on one side and grey on the other. The stuff I used
> was Weldaite and opaque white in colour - does this matter ?

Type of grease matters to how long it will last, but not to how well it
works to begin with. Weldite is OK but not the longest-lasting.

> 3) I got the axle out OK without undoing the 17mm locking bolt that
> requires a 17mm cone spanner but can't adjust properly when
> refitting. Is there a bodge to avoid buying a 17mm cone spanner
> (£5.95 - professional tool) - or is there a tool with other useful
> stuff on it that includes a 17mm cone spanner that would be more cost
> effective ? I'll probably only use it a few times before the next bit
> of technology comes along and makes it obsolete.

Get a cheap pair of cone spanners from www.inmotionproducts.com * (formerly
Mike Dyason (retired)). They're only made of pressed relatively-soft steel,
but still they last well enough when used on normally-tightened cones, ie.
not stupid tight.
Buy some other stuff at the same time to justify the postage charge!

* Website not working at the moment. Try later.

~PB

 

[Rob Morley]

In article <[email protected]>, anern
[email protected]n says...
> Hi,
> I'm halfway through rebuilding my M760 rear hub and have run across a
> couple of problems :
> 1) I can't get the bearings to run smooth with little play (new ones) -
> question : is there any variation in bearing qauilty ? I was told they're
> all the same nowerdays.

While there may be some substandard ball Bearings around, their
shortcomings would most likely be shown by poor wear characteristics
rather than poor dimensional tolerances.

> I made sure everything is spotless. The hubs were
> perfectly smooth when new.

Bearing adjustment can seem fine off the bike, but when you fit the hub
and tighten the QR skewer it's subject to extra axial load. Check this
by packing out the axle stubs with washers and fitting the skewer, so
you can feel how smooth the bearing is off the bike

> 2) I used lithium grease though the stuff that was in there before was
> taslucent green on one side and grey on the other. The stuff I used was
> Weldaite and opaque white in colour - does this matter ?

It matters in as much as the grey grease probably started out off-white,
and has become grey because it's loaded with steel particles that have
worn off the bearing surfaces.

> 3) I got the axle out OK without undoing the 17mm locking bolt that requires
> a 17mm cone spanner but can't adjust properly when refitting. Is there a
> bodge to avoid buying a 17mm cone spanner (£5.95 - professional tool) -or
> is there a tool with other useful stuff on it that includes a 17mm cone
> spanner that would be more cost effective ? I'll probably only use it a few
> times before the next bit of technology comes along and makes it obsolete..
>
I doubt that cone spanners are going to go away any time soon. The
spanner costs about as much as a pair of XT cones. From the sound of it
your hub is scrap, or at least part knackered - proper application of a
cone spanner could have prevented that.

 

[Pete Biggs]

Rob Morley wrote:
> While there may be some substandard ball Bearings around, their
> shortcomings would most likely be shown by poor wear characteristics
> rather than poor dimensional tolerances.

I've seen grade 1000 balls (wrongly) advertised as being suitable for
bicycle bearings. By definition, these have poor dimensional tolerances
compared to grade 100. But I don't suppose the difference would be
noticeable straight away.

> From the sound of
> it your hub is scrap, or at least part knackered - proper application
> of a cone spanner could have prevented that.

To be a little more optimistic, Anern might just not have it adjusted as
well as possible yet.

~PB

 

[Rob Morley]

In article <[email protected]>, Pete Biggs
[email protected] says...
> Rob Morley wrote:
> > While there may be some substandard ball Bearings around, their
> > shortcomings would most likely be shown by poor wear characteristics
> > rather than poor dimensional tolerances.
>
> I've seen grade 1000 balls (wrongly) advertised as being suitable for
> bicycle bearings. By definition, these have poor dimensional tolerances
> compared to grade 100. But I don't suppose the difference would be
> noticeable straight away.

Weldtite bearings are grade 1000, and specifically sold for bikes. I'd
never bothered to check before, assuming they'd be good enough (they're
OK for cheap components, but not for better ones). The simple solution
is to buy from a bearing factor, rather than a bike shop where you can't
be sure what's in the little cellophane bags.
>
> > From the sound of
> > it your hub is scrap, or at least part knackered - proper application
> > of a cone spanner could have prevented that.
>
> To be a little more optimistic, Anern might just not have it adjusted as
> well as possible yet.
>
Having serviced quite a few Shimano hubs in my time I'm afraid it's
likely that the cups are worn unevenly, and fitting new cones won't fix
the problem.

 

[renum]

anern wrote:
> 1) I can't get the bearings to run smooth with little play (new ones) -
> question : is there any variation in bearing qauilty ? I was told they're
> all the same nowerdays. I made sure everything is spotless. The hubs were
> perfectly smooth when new.

To add to what others have said, you could have got grade 25 bearing
from simplybearings.co.uk, they aren't that cheap though.

> 2) I used lithium grease though the stuff that was in there before was
> taslucent green on one side and grey on the other. The stuff I used was
> Weldaite and opaque white in colour - does this matter ?

"It will do", but it is not uber long lasting, nor very resistant to water.

> 3) I got the axle out OK without undoing the 17mm locking bolt that requires
> a 17mm cone spanner but can't adjust properly when refitting. Is there a
> bodge to avoid buying a 17mm cone spanner (£5.95 - professional tool) - or
> is there a tool with other useful stuff on it that includes a 17mm cone
> spanner that would be more cost effective ? I'll probably only use it a few
> times before the next bit of technology comes along and makes it obsolete.

Choices:
- Go to Wilko, IIRC, they have a cheapo flat multi tool with a cone
spanner on one end.
- Find a lidl, last week the one round where I live had a special with
one of those bike toolkits for £20, which included 2 large cone
spanners. Look at the lidl site to determine if the store near you
had/has that particular special offer on before going.

 

[Ben C]

On 2008-04-15, Rob Morley <[email protected]> wrote:
[...]
> Having serviced quite a few Shimano hubs in my time I'm afraid it's
> likely that the cups are worn unevenly, and fitting new cones won't fix
> the problem.

I'm inclined to agree with that assessment. But if you have a hub like
that and you set it up as tight as you can (so no binding, and therefore
a bit of play, because it is worn) you can carry on riding it around
like that for a good long while. You don't notice a small amount of play
in normal riding.

 

[anern]

> - Find a lidl, last week the one round where I live had a special with
> one of those bike toolkits for £20, which included 2 large cone
> spanners. Look at the lidl site to determine if the store near you
> had/has that particular special offer on before going.

I got one of these last year but it does'nt have a 17mm one. I just bought a
cyclo tool (£5.95, LBS) so I'm going to have another go, see if I can get
them smooth. They've only done 6000-7000 miles, I should get more life out
of them than that.

For my next batch, I'm going to try
http://www.merlincycles.co.uk/?fn=product&productId=115&categoryId=21, for
grease is this any good ?
Thanks for all the help,

Bruce.

 

[Pete Biggs]

anern wrote:
>> - Find a lidl, last week the one round where I live had a special
>> with one of those bike toolkits for £20, which included 2 large cone
>> spanners. Look at the lidl site to determine if the store near you
>> had/has that particular special offer on before going.
>
> I got one of these last year but it does'nt have a 17mm one. I just
> bought a cyclo tool (£5.95, LBS) so I'm going to have another go, see
> if I can get them smooth. They've only done 6000-7000 miles, I should
> get more life out of them than that.

Certainly have another go, but wreckage is possible even after 60-70 miles
if the bike has been ridden with the bearings badly adjusted or lubricated,
let alone 6000-7000.

> For my next batch, I'm going to try
> http://www.merlincycles.co.uk/?fn=product&productId=115&categoryId=21,
> for grease is this any good ?

It's quite thin, but I think it's good.

~PB

 

[Pete Biggs]

Rob Morley wrote:

>> To be a little more optimistic, Anern might just not have it
>> adjusted as well as possible yet.
>>
> Having serviced quite a few Shimano hubs in my time I'm afraid it's
> likely that the cups are worn unevenly, and fitting new cones won't
> fix the problem.

That may be a common sight at bike shops with neglected bikes that are taken
in for service as a last resort, but I still think it's just as likely that
this hub simply isn't adjusted properly. This is after the OP has made an
attempt. It takes some practice for the home amateur mechanic to adjust a
hub properly. Get it wrong and you get the symptoms described.

~PB

 

[anern]

> > I just
> > bought a cyclo tool (£5.95, LBS) so I'm going to have another go, see
> > if I can get them smooth. They've only done 6000-7000 miles, I should
> > get more life out of them than that.
>
> Certainly have another go, but wreckage is possible even after 60-70 miles
> if the bike has been ridden with the bearings badly adjusted or
lubricated,
> let alone 6000-7000.
>
> > For my next batch, I'm going to try
> > http://www.merlincycles.co.uk/?fn=product&productId=115&categoryId=21,
> > for grease is this any good ?
>
> It's quite thin, but I think it's good.
>
> ~PB
>
>

I've re-done it with the new tool and it seems OK - time will tell. I
thought thinner bearing lubes were prefered by racers, I was looking for
somthing a resilient and long lasting as possible, I just assumed that since
the MTB'ers were using it, this would be the case. I'm a touring/transport
cyclist.

One thing I still don't understand is why the old grease was a different
colour on the cassette side from the stuff on the oposite side.

Thanks for all your help.

Bruce.

 

[renum]

anern wrote:
> One thing I still don't understand is why the old grease was a different
> colour on the cassette side from the stuff on the oposite side.

Could have been exposed to contaminants/water/dirt etc...

 

[Pete Biggs]

anern wrote:
> I've re-done it with the new tool and it seems OK - time will tell. I
> thought thinner bearing lubes were prefered by racers, I was looking
> for somthing a resilient and long lasting as possible, I just assumed
> that since the MTB'ers were using it, this would be the case. I'm a
> touring/transport cyclist.

Finish Line Premium has been OK for me so far, but I've not left it long
enough between services to give its durability a really good test.

Marine grease might be best for you. Try a supplier of boat equipment.

~PB

 

[Rob Morley]

In article <[email protected]>, renum
[email protected] says...
> anern wrote:
> > One thing I still don't understand is why the old grease was a different
> > colour on the cassette side from the stuff on the oposite side.
>
> Could have been exposed to contaminants/water/dirt etc...
>
They were different types of grease - that weird Shimano fluorescent
green stuff on one side and what I'm assuming was once white waterproof
grease (but could have been moly grease) on the other.

 

[Rob Morley]

In article <[email protected]>, Pete Biggs
[email protected] says...
> Rob Morley wrote:
>
> >> To be a little more optimistic, Anern might just not have it
> >> adjusted as well as possible yet.
> >>
> > Having serviced quite a few Shimano hubs in my time I'm afraid it's
> > likely that the cups are worn unevenly, and fitting new cones won't
> > fix the problem.
>
> That may be a common sight at bike shops with neglected bikes that are taken
> in for service as a last resort, but I still think it's just as likely that
> this hub simply isn't adjusted properly.

It happened to my own Ultegra hub many years ago, before I figured out
that you need to adjust them with the skewer fitted and cranked up
tight. It doesn't take long running a hub too tight for the the bearing
surfaces to deform, even though they may not be obviously grooved or
pitted. As someone else has pointed out you can adjust a hub that's
damaged in this way so it's not binding and it will often remain
serviceable for ages with just a bit of slack, although I've found it's
less than ideal for the front hub on a racer - if I rode mine no-hands
the front would develop a progressive shimmy.

 

[CJ]

On 16 Apr, 06:58, Rob Morley <[email protected]> wrote:
> In article <[email protected]>, renum
> [email protected] says...> anern wrote:
> > > One thing I still don't understand is why the old grease was a different
> > > colour on the cassette side from the stuff on the oposite side.
>
> > Could have been exposed to contaminants/water/dirt etc...
>
> They were different types of grease - that weird Shimano fluorescent
> green stuff on one side and what I'm assuming was once white waterproof
> grease (but could have been moly grease) on the other.

Whenever I've opened a new-ish Shimano hub (to modify it for external
grease injection, so I never have to open it again!) I've always found
the same green translucent grease in both sides. I think the grey gunk
is the same grease, with added water, grit and powdered steel.

An SKF bearing catalogue I have says that grade 10 is for precision
bearings, grade 100 for general engineering purposes, grade 1000 for
ball catches, furniture castors and the like. We know that Campag use
grade 25 and Shimano grade 40. Grade 1000 has no place on any
reasonably good quality bicycle.

Frankly, I wouldn't trust a firm that supplies grade 1000 balls as
suitable for bicycle hubs to know any more about grease than its
price! Ordinary lithium grease is better than nothing of course, but
not optimised for the high load, low speed, poorly sealed conditions
of bike components.