seized rear hub!

[dlv13]

i have just had the strangest breakdown , setting off for a few days cycle camping about 10 miles along the road the rear wheel starts rubbing on the chain-stay investigating all the usual obvious things all seems ok but the wheel will not stay true in the frame or turn easily , with the panniers on its a bit hard to get a good look .
to cut a long story short on moving the bike forward to see if the problem can be identified the quick release skewer snaps , ! end of trip ,,,
then the problem is visible for some reason the hub lock ring has been unscrewing itself spreading the rear frame to the point of snapping the skewer, the axle is seized into the hub and is turning in the frame ,,, i am suspecting a broken axle , . after a long walk home, i take things to bits expecting to find something broken . other than incredibly over tight cones. all looks ok ???

now i had fairly recently serviced the hubs so it is possible that i had not tightened a lock nut properly but this is a job i have done many times over many years and never had any problems before, i am also meticulous about tightening the lock nut cone setup as i know this is something i do not carry tools to sort at the roadside if it does comes loose , the only thing i could find wrong was the free-hub that the cassette fits on was half a turn loose !.

i found this post on another forum http://singletrackworld.com/forum/topic ... what-to-do
read the 7th post down

so this is a guess at what i think may have happened with me ,
the free hub is not tightly screwed onto the rest of the hub, on freewheeling the movement between the moving hub and the non moving free hub tightens it up effectively making the bearings loose , the action of the revolving wheel causes one of the cones to screw inwards away from the lock-nut into the the hub really tightening things up and seizing the wheel .the now solitary lock-nut unscrews itself on the revolving axle as i turn the wheel trying to fathom out what is wrong spreading the frame and snapping the skewer ,,

i will now start checking the tightness of the free hub something i have perhaps wrongly never paid any attention too . this needs a very big allen key that i also do not carry on tour .

the worst aspect of this that because i do not understand what has caused this to happen its shattered my confidence in bike reliability .
has anyone else had similar experiences or any thoughts as to why this has happened . as i really would like to know what went wrong ,
the hub is a shimano 105

[NATURAL ANKLING]

Hi,
If you are talking the freehub hollow bolt, never exactely found one loose when I strip them down from new (mostly mine / old bikes that have never been worked on).

If you ever touch it be carefull to clean well..............and this is one of those occasions when I do add grease to thread copiously and all over the bolt.

The bolt is steel and threads into aluminium so grease will be needed not to gall the threads.
I do this up pretty tight with a key only about 9" long with firm hand pressure (don't use a longer wrench!)

But of course the thread though long, is into aluminium and you could just end up overdoing it which would be apparent at the time of tightening.

Either the thread into the hub was worn / damaged or it was not done up / enough.

Once the hub has gone through this undoing process I would probably junk the hub as the seating of freehub will be worn concave, and will fail again soon!

[dlv13]

yes the free hub hollow bolt if that its name , it was loose. never had need to take this one off . i am still considering options on how to move forward from this . but i doubt very much i will be using this hub again , if this is caused by looseness between the freehub and main hub which reading the other forum thread seems to be something in common , then it could happen again ,no thanks

[meic]

Normally these freehubs are attached with bolts "as tight as car wheel nuts", meaning having to lean on the 8-10" long allen key with your whole weight.
Rebuild it with a similarly excessive torque and you should be fairly convinced that it will stay put.
The worst that can happen by trying this is that you strip the thread (I wonder if you can?), but you were giving up on the wheel anyway.

[NUKe]

Normally these freehubs are attached with bolts "as tight as car wheel nuts", meaning having to lean on the 8-10" long allen key with your whole weight.
Rebuild it with a similarly excessive torque and you should be fairly convinced that it will stay put.
The worst that can happen by trying this is that you strip the thread (I wonder if you can?), but you were giving up on the wheel anyway.

Agreed but if you have one I would find out the torque setting and use a torque wrench.

[Brucey]

having rebuilt hundreds of hubs with freehub bodies that are attached this way I can say that to have the bolt be slightly loose isn't at all uncommon. I check these bolts are tight even if the freehub body isn't removed from the hub and about half of them will tighten a little more and about one in ten is slack enough that it may work loose down the line. The reason this happens is (I think) that the freehub body can settle into the hubshell a bit more. Shimano's MTB hub models have always had a steel washer between the hubshell and the freehub body, which is intended to help prevent such settling.

However.... if you have had a problem of the sort you describe, I would hesitate to put the blame on a loose freehub. I would say that it is far more likely that the cone worked loose on the RHS first, and that this precipitated the chain of events that bust everything. BTW I agree with the proposed chain of events for the most part, but I think the freehub body would almost certainly have loosened as a result of everything else, rather than was the cause of all the trouble.

[NB the axial loading caused by a precessing cone/binding bearing is enough to cause the hub centre to go into yield; it is also enough to cause a freehub body to settle a little further into the soft alloy hubshell.]

The RH cone in a freehub is vulnerable to precession; IGH manufacturers are familiar with this; in SA hubs there has always (until recently, when some idiot deleted it) been a RHS tab washer to prevent the cone from screwing in, and Sachs/SRAM IGH hubs have the RH cone screwed up against a shoulder.

In a shimano freehub you have two options;

1) do the RH cone and locknut up darned tight and/or
2) use threadlocking compound on the RH cone and locknut

How tight is darned tight? About 15-20 ftlbs, depending on the parts ( NB you might strip threads if you are not careful...). Note that if you have vertical dropouts, it is tempting not to do the QR up very tight; this would be a terrible mistake, because the pressure from the QR also helps to keep the RH cone/locknut in place.
It is also a bad idea to adjust the hub so that there is no free play in it; it ought to be set so that there is a little free play that just disappears as the QR is tightened. If there isn't any such free play, this greatly helps the forces of precession to start the RH cone moving, because the bearing is under enormous load whether the bike is loaded or not.

So it might just be one of those unlucky things, but in future you might like to consider that you

a) use threadlock on well-tightened RH cone and locknut
b) use an MTB hub for loaded touring, rather than a 'road' model
c) be sure that the hollow bolt is tight; (you can use threadlock on it, but this won't help if the freehub body settles)
d) be sure to adjust the hub correctly (so that QR pressure doesn't overload the hub bearings)
e) be sure to tighten the QR fully.

cheers

[NATURAL ANKLING]

Hi,
Never had a cone locknut come loose but you always tighten the RH side so tight that it will never move when you get round to adjust the hub bearings, as if the RH side loosens then you have to remove / push it far right after loosening the LF locknut to re-tighten!
Once stuffed we will never know but prudent to check the hollow bolt and check the RH locknut too, when you service hubs at all.

Not sure what the bicycle service manual suggests on rear locknuts?

[Brucey]

BTW that freehub bodies usually 'become loose' via settling (rather than the bolt backing out) is evident when retightening them after a period of use. It is nearly always the case that the bolt is reluctant to move at all, but once shifted, it moves a little easier even if it goes ~1/8th of a turn or so. Such sticking friction is not at all suggestive of a bolt that has been on the move previously. Needless to say if the settling is bad enough, the one thing might eventually lead to the other, but the usual course of events is that way round.

cheers

[dlv13]

its starting to look like i just did not tighten the righthand side locknut enough and ive paid a heavy price for my mistake
as it was the rh side that unscrewed and spread the frame snapping the skewer.

as suggested
i think in future i am going to use thread lock and really tighten it up, then access the hub from LHS never undoing the RHS

The RH cone in a freehub is vulnerable to precession; IGH manufacturers are familiar with this; in SA hubs there has always (until recently, when some idiot deleted it) been a RHS tab washer to prevent the cone from screwing in, and Sachs/SRAM IGH hubs have the RH cone screwed up against a shoulder.

i seem to remember solid axles i was using back in the 1980s having a shoulder on them , never could understand what it was for ,,, now i know

b) use an MTB hub for loaded touring, rather than a 'road' model

i hear you, but its a old frame and its OLN is for road hubs , just a thought thats occurred to me would it be possible to fit a mtb hub into a 130mm road spacing by using narrower axle spacers on LHS losing the extra 5mm ?, dishing adjusted to keep rim central ,has anyone done this ?

[Brucey]

yes you can respace most MTB (rim brake) hubs to 130mm without great difficulty. In practice ~132mm will go into most '130mm' frames without any problems.

cheers

[dlv13]

this is really starting to screw my head up ,,, thinking about fitting a 135mm mtb hub into my 130mm frame, and getting really confused about the wheel dishing ,,,, will not the dishing stay the same as with a 130mm hub ? ,as the rim needs to be central in the frame which is central between the dropouts the distance from RH locknut to RH hub flange is the same on either sized hub and the rim is on same centre line so spoke angle will be same on the dished side on 130mm hub or 135 mm hub ? and only less steep on LH side if some of the extra 5mm is used to make distance between flanges greater ? so the 135mm hub wheel will not be stronger through less dishing? in a 130mm spaced frame the RH flange / rim / lock nut positions = dishing are all the same either hub ?? ?
anyway regardless i appreciate that there are other reasons that a mtb hub is more suited for loaded touring so at the moment i am thinking new back wheel , deore lx hub / sputnik rim

[MikeDee]

yes you can respace most MTB (rim brake) hubs to 130mm without great difficulty. In practice ~132mm will go into most '130mm' frames without any problems.

cheers

Without changing the wheel dish and not have spoke length problems? I guess you mean a bare hub and take a 5mm spacer off the left side and fit a shorter axle? Mountain bike hubs used to be available in 130 spacing. No more?

[Brucey]

if you are respacing an accurately built wheel from 135mm to (say) ~132mm and you don't redish accordingly the rim will have a 1.5mm error in position between the brakes. Plenty of wheels/frames are built that far off to start with. When you re-dish, it will only be about one turn on the spokes, so no 'spoke length problems'.

cheers

[rjb]

This is a timely post. I had a puncture yesterday on the rear wheel of the tandem, Shimano M475 disc hub. Having repaired the inner tube i replaced the wheel but it had excessive play. Tightened the cones to attempt to elimante the play but even when fully tightened to the point that they were binding i couldnt eliminate the excess play. At this point i noticed the play appeared to be at the freehub where it joined the hub. On stripping the hub i found the freehub retaining bolt to be loose and required approx a full turn to tighten it. Test ride today and what i noticed was that the vague feeling which i had experienced in the preceeding weeks that i had a soft tyre on the back had disappeared. I had previously drilled the hub to enable grease injection and wonder if this had contributed to the retaining bolt loosening. I assume these bolts are inserted relatively dry during manufacture with no lubricant and they are not expecting to see any in use. Any opinion on this. Thanks all.

[Brucey]

it might be worth taking it all apart and then cleaning the screw thread of the hollow bolt before refitting it with some thread locking compound. This won't prevent the freehub from going loose again if the original cause was settling at the interface between the freehub body and the hubshell, but it might prevent the bolt from being damaged if you ride on it whilst it is loose.

I don't think that having the hub well lubricated ought to have hastened the problems you have had; I think it is more likely that the rigours of tandem service are responsible.

cheers