105 front hub - seals interfering with bearing adjustment

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Pneumant
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Joined: 7 Oct 2010, 8:25pm

105 front hub - seals interfering with bearing adjustment

Post by Pneumant »

I stripped down & regreased a 1-year old 105 5700 model front hub this morning (to investigate a 'roughness' felt through the bars with the front of the bike lifted) and had a devil of a job re-adjusting the bearing play. The hub was either ridiculously tight or too loose or it would appear to be adjusted and then inexplicably lose its adjustment when spun. I tried a fresh set of decent bearings with the same results. After 2 hours I was really fed up!
After a rejuvenating cup of Tea and a contemplative biscuit I pondered the unusual design of this hub. Eleven balls crammed in per-side and seals which look like they are an afterthought. I decided to assemble without the internal seals (part number 8 on the attached diagram). I knew I was onto something here when the hub adjusted up perfectly first time. These seals were undoubtedly the cause of the initial roughness. I can only think they somehow had become distorted in service? I initially removed them with care - in fact they popped out easily with light finger pressure. The hub spins very freely now with zero roughness - perfect! I imagine / hope the sealing on this hub is still OK, after all the cone/dustcover are a close fit to the hub-body. Anyone else experienced this seal problem?
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Brucey
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Re: 105 front hub - seals interfering with bearing adjustmen

Post by Brucey »

from your description I am almost 100% sure that one or more of the balls was misplaced when you reassembled the hub first time round.

What can happen is that if you one ball sits slightly outside of the cup, it makes adjustment impossible, and the hub will feel as rough as a rough thing with added extra roughness. If you are curious to see if this has really happened, examine the balls and the edge of each cup for marks, using a x20 lens or a microscope. I would expect you to see marks.

I nearly destroyed a shimano front hub like this in about 1982. I got as far as riding it a mile down the road and back again. I could tell that all was not well, and when I stripped the hub there was a broken (crunched into tiny pieces) ball bearing inside. Fortunately the hub survived (just).

Very many shimano front hubs can be reassembled badly like this; there is very often enough room between the back of the seal/dustcap and the edge of the cup insert for a ball to sit wrongly. If there are contact seals they will drag because the cone is now off-centre. A misplaced ball may even dislodge a seal axially and make it drag more than normally. When you reassemble the hub you need to stick the balls in place using grease, and to be sure that you don't give the cone a chance to lift a ball out of position (so don't wiggle the axle back and forth with the adjustment very slack, this will allow the balls to get into the wrong places). By contrast with shimano rear hubs you can almost throw the balls into the space and they find their own way quite nicely; you almost can't go wrong with rear hubs.

A good test for the balls being in the right place is to finger tighten the cones (as much as possible using fingers alone) and to turn the hub. If the hub turns with little resistance then all is well, and you can proceed to adjust the hub correctly (i.e. with a little slack that just disappears when the QR is tightened).

BTW I would expect the hub to have been adjusted way too tight originally; shimano hubs usually are like this out of the factory.

hth

cheers
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NATURAL ANKLING
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Re: 105 front hub - seals interfering with bearing adjustmen

Post by NATURAL ANKLING »

Hi,
I have got a "Joy Tech" front hub with mechanical seals, 10 balls a side :?:
Is that right ? Feels ok but will take apart again to check ball size ?
I always have found that balls were odd numbers in loose bearings on cycles ?
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Pneumant
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Re: 105 front hub - seals interfering with bearing adjustmen

Post by Pneumant »

Thanks Brucey, I will try and readjust when I get a spare moment taking super-care as advised, will post back if this has made a difference. I have a x10 botanical use lens so will also check the bearings for marks :)
Pneumant
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Re: 105 front hub - seals interfering with bearing adjustmen

Post by Pneumant »

Well I tried and failed (again).
Careful assembly, grease holding bearings in place and same results as before .
Remove the seals (as before) and the hub adjusts up perfectly. Attempting to adjust this hub with the seals in place is just like adjusting a cheapo BSO hub - frustrating & futile! I guess these seals really have become distorted and useless.
So away with these daft seals and memo to self to avoid this design of hub in the future. Thanks for the advice Brucey - much appreciated :D
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NATURAL ANKLING
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Re: 105 front hub - seals interfering with bearing adjustmen

Post by NATURAL ANKLING »

Hi,
Is it the dust cover (metal ?) on the cones which might have slipped in which foul the seals ( rubber / plastic ?)
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Pneumant
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Re: 105 front hub - seals interfering with bearing adjustmen

Post by Pneumant »

NATURAL ANKLING wrote:Hi,
Is it the dust cover (metal ?) on the cones which might have slipped in which foul the seals ( rubber / plastic ?)

These parts look OK. To be honest I can't see this hub being any worse-off for weather sealing minus these seals when compared to lots of other cup & cone hubs.
Johnnyv
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Re: 105 front hub - seals interfering with bearing adjustment

Post by Johnnyv »

Bumping a very old thread because I have the exact same problem. Did you ever figure out a solution? I don't want to junk the hubs

I've tried many times with the seals but can't get them right. If I do it with no seals I get them spinning perfectly

Thanks
cromo
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Re: 105 front hub - seals interfering with bearing adjustment

Post by cromo »

I would be tempted to try assembling the bearing with the seal, but leave out one ball bearing per side. Maybe you have already tried this?
Samuel D
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Re: 105 front hub - seals interfering with bearing adjustment

Post by Samuel D »

How rough is rough?

I have the same hub. The seals create detectable drag when spinning a light wheel off the ground, and they might make discernible noise with an ear as close as you dare to the spinning hub – in comparison to the same hub with the seals removed.

But! I once did a rough calculation of the energy loss in a spin-down test. The average power dissipation of the seals in the hub turned out to be well under one-quarter of a watt.

So spinning a wheel off the ground reveals effects that are, practically speaking, irrelevant to performance.
Brucey
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Re: 105 front hub - seals interfering with bearing adjustment

Post by Brucey »

further to the above I have noticed that some shimano front hubs are not machined perfectly concentrically, i.e. the hubshell swashes slightly when the wheel rotates. Even if the hub is set up perfectly the seal drags a tiny bit more than it should, because it is not perfectly centred over the cone. Fortunately the seal is squashy enough that the sealing still works OK.

With a 5700 (or an LX hub which is of similar design) if there is a distinct (and abnormal) rubbing it could mean that the seal is touching the back of the dustcap or it is possible that the dustcap is just touching the bore of the hub. In either case there would be rubbing marks accordingly. T guard against the former it is a good idea if the seal is not removed unless it is absolutely necessary.

Needless to say the correct adjustment is in any case a little free play that just disappears as the QR is tightened fully. This can require that the cone is adjusted to 1/100th of a turn, i.e. much more precisely than most folk ever do it.

If the seals are dragging slightly (in the normal way) then this effect can be mitigated to some extent by using a semi-fluid grease instead of the usual #2 stuff.

cheers
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Pneumant
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Re: 105 front hub - seals interfering with bearing adjustment

Post by Pneumant »

Johnnyv wrote:Bumping a very old thread because I have the exact same problem. Did you ever figure out a solution? I don't want to junk the hubs

I've tried many times with the seals but can't get them right. If I do it with no seals I get them spinning perfectly

Thanks


Three years on absolutely no issues with running this hub (on a summer bike) minus the seals. It runs as sweet as ever. If you use the bike through the winter like this be prepared to re-grease the hub - actually this is hardly an onerous task if the bearings can be quickly brought into adjustment which is the point where this post started!
Brucey
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Re: 105 front hub - seals interfering with bearing adjustment

Post by Brucey »

the correct adjustment is defined by an absence of free play, just, (either following a small adjustment with a solid axle, or following tightening the skewer with a QR hub). Whether the seals are present or not is irrelevant to this.

Taking the seals out entirely is a bit mad TBH; that it doesn't cause instant failure is only to be expected though; after all seals were not fitted to most hubs for many decades...

IME if a shimano hub of moderate quality is adjusted properly and lubricated properly (i.e. with a generous fill of semifluid grease) it will go many tens of thousands of miles without further attention.

The seals will by contrast wear and fail more quickly if they are lubricated with a #2 grease, because the lubricant film at the seal lip isn't renewed in the same way.

cheers
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