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Old 01-15-10, 11:50 PM   #1
electrik
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Deore m-475 hub worse seals than titanic.



Above is the cursed item, just took them apart for some cleaning during a January thaw and the disc side bearings/cups were half rusted, after a month or so of winter riding.

Will they last till spring? This hub has one measly little o-ring seal(say hi to NASA for me shimano)

Has anybody come up with some DIY type seal i might be able to find, currently the cone flange is submerged under a slathering of grease.
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Old 01-16-10, 08:02 AM   #2
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Those hubs come from the factory with very little grease and are often adjusted too tight. A complete overhaul using a good waterproof grease before the hub is ever installed on a bike is the only way to make them last.
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Old 01-16-10, 09:57 AM   #3
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There should be two plastic rings in there for seals. O-rings are not made for that application.
http://techdocs.shimano.com/media/te...9830608924.pdf
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Old 01-16-10, 10:16 AM   #4
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o rings might work better than those two plastic rings shimano calls seals. its just a really cheap oem hub. the 525 is much better and like 3 dollars more
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Old 01-16-10, 10:20 AM   #5
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Yes, they could indeed seal the hubs much more effectively but then you would complain just as bitterly about the drag.

Clean the hubs out, refill them with copius amounts of grease and reassemble. The excess grease will leak out for the first couple of rides but it will act as a much more effective seal and keep water, dirt, etc. out of the hubs. I have hubs on my "rain bike" that are 20,000 miles old and the original cones and races are still in excellent condition because I overpack them with grease.
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Old 01-16-10, 10:40 AM   #6
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I have the same kind of hub. The metal dust cap in the hub split partway up the inner diameter where it fits around the cone, perhaps as it was being made.

I would use an o-ring myself but I think it would get shredded. Examine your hub to see if the surface the o-ring would seal against is smooth.

I don't personally think an o-ring would create too much drag in that application.

Try one of the square profile o-rings because it has two sealing surfaces and would help prevent the groove from filling with dirt.

The hub is a Nexave component. It is really for comfort bikes, I think.
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Old 01-16-10, 02:34 PM   #7
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The first thing I did with the hub(which came on the wheel I was buying and was simply listed as "deore") was disassemble it, remove the factory grease, repack with a heavier marine grease and then re-adjust the cones to satisfaction. I see now that the o-rings i was speaking about are just "seals" according to Shimano, but they don't work very well(at all, well, maybe at keeping larger debris out). I was hoping i could slip on some external sealing gaskets i had from an older parallax hub but, they won't fit because of the way the hub shell bows out.

I'm just going to over-pack and coat with grease the hub and outer-shell. I'm not sure if i can sneak an o-ring on there, maybe a trip to the hw store is in order - Though I assume the hub is almost gone anyways now(500km!) since there is rust and presumably the associated pitting on the inner race-way which will cause excessive wear.

Here is the techdoc m475 front hub. The above posted one is for the rear-hub

Last edited by electrik; 01-16-10 at 02:39 PM.
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Old 01-16-10, 03:18 PM   #8
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I'm just going to over-pack and coat with grease the hub and outer-shell. I'm not sure if i can sneak an o-ring on there, maybe a trip to the hw store is in order - Though I assume the hub is almost gone anyways now(500km!) since there is rust and presumably the associated pitting on the inner race-way which will cause excessive wear.

Here is the techdoc m475 front hub. The above posted one is for the rear-hub
One of the issues with overpacking hubs is that the grease tends to migrate onto the axle, where the spinning hub pushes it along the threads and out past whatever "seals" are present. Migrating grease eventually splatters on the brake disc or rim- bad for the brakes.

I'd put in the "right" amount of grease- enough to pack the balls, but not so much that it's wasted. Replace the cones if they're pitted, inspect the races, grease, adjust and go ride.
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Old 01-16-10, 03:26 PM   #9
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The first thing I did with the hub(which came on the wheel I was buying and was simply listed as "deore")...
Was it by any chance on some WTB Speeddisc rims with 32 black spokes?

I burned the cones on mine. Wheelsmfg lists the 475 as a nexave.
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Old 01-16-10, 04:03 PM   #10
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I'd put in the "right" amount of grease- enough to pack the balls, but not so much that it's wasted. Replace the cones if they're pitted, inspect the races, grease, adjust and go ride.
Right side cone and race have rust on them already.. i'm just going to ride after the repack and then check a bit earlier on the wear, hopefully the rust will break free into the fresh grease shortly and i can get most of it out that way.

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Was it by any chance on some WTB Speeddisc rims with 32 black spokes?

I burned the cones on mine. Wheelsmfg lists the 475 as a nexave.
No it came on some SUN Rhyno Lite rims, unfortunately the XT hub were not in stock.
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Old 01-16-10, 04:38 PM   #11
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One of the issues with overpacking hubs is that the grease tends to migrate onto the axle, where the spinning hub pushes it along the threads and out past whatever "seals" are present. Migrating grease eventually splatters on the brake disc or rim- bad for the brakes.
I'm not advocating putting in a huge amount of excess but I do fill the cavities on each axle end nearly completely full. The grease does ooze out past the seals for a couple of rides but never gets beyond the dust covers or hub flange and has never gotten on the rims or anywhere else.

I use Phil Grease which is only moderately heavy bodied but has never caused any migration problems and it does make my hubs last a long time
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Old 01-16-10, 04:53 PM   #12
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I'm not advocating putting in a huge amount of excess but I do fill the cavities on each axle end nearly completely full. The grease does ooze out past the seals for a couple of rides but never gets beyond the dust covers or hub flange and has never gotten on the rims or anywhere else.

I use Phil Grease which is only moderately heavy bodied but has never caused any migration problems and it does make my hubs last a long time
Unfortunately there are no dust covers on these hubs...
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Old 01-16-10, 05:00 PM   #13
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Unfortunately there are no dust covers on these hubs...
I think there are. They're in the hubs, not pressed around the cones. If you stick your finger in where the cone is supposed to go you will feel that it's a pressed-in sheet metal cover. The edge may be jagged though.
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Old 01-16-10, 07:25 PM   #14
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My Deore disc hubs (have had 2 sets) came with dust covers, that was the first thing I noticed. The only axle end that didn't is the freehub itself. My first set lasted three years of near-year-round riding, before the rear rim split along a spoke hole. The other set is still going -- on a bud's bike, he traded me a set of Mavic 819's with Cannondale disc hubs, straight up. He hated the feel of the 819's, and wanted a 2nd set for his bike; I love the things!
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Old 02-06-10, 03:06 PM   #15
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Got around to pulling the wheel apart again... the over-packing with grease seems to have helped, but conditions haven't been that sloppy since i last posted. You can see the pitting/rust some of which came out.
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Old 02-06-10, 03:56 PM   #16
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It sure looks like you may have excessive quick release tension from the way the pitting goes all the way around the cone after not that much use. Or, the cones could be adjusted too tight, so that normal skewer closure makes them too tight. Anyone else concur? Not that it's a good thing to have rust and water in your hub.
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Old 02-06-10, 04:26 PM   #17
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It sure looks like you may have excessive quick release tension from the way the pitting goes all the way around the cone after not that much use. Or, the cones could be adjusted too tight, so that normal skewer closure makes them too tight. Anyone else concur? Not that it's a good thing to have rust and water in your hub.
That would be my assessment too, although I couldn't be sure, doesn't look like damage from poor seals to me though, I've ran many old hubs that have no seals other than dust caps and have ridden them through several winter seasons repacking about once per month (which I usualy find to be unnecessary but I'm fine paying sub one dollar every month for peace of mind)
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Old 02-06-10, 04:38 PM   #18
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Well, you may be right about the tensioning but i try to leave some play in the cups and cones. I've not had wear issues with the opposite side's races they look brand new. The damage was done mostly by salt-water intrusion, after i pulled the wheel apart the right side(pictured) was full of rust and rust grease, it had already been going for a month or so that way.

The most recent pictures are from today... and by over applying grease there hasn't been further slushy salt water getting past the dust seals.
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Old 02-06-10, 05:59 PM   #19
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hub is toast
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Old 02-06-10, 07:23 PM   #20
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hub is toast
Yah, but still going to use it till winter is over... might as well
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Old 02-06-10, 07:25 PM   #21
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Is it possible you had too much preload on the bearings? There is fair amount of fretting on the cones as well as the hub race.
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Old 02-06-10, 07:35 PM   #22
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Is it possible you had too much preload on the bearings? There is fair amount of fretting on the cones as well as the hub race.
I figured that was just from rust breaking free and occasionally getting stuck between the race and the bearing resulting in material transfer... that is another possible cause i think.

I'm pretty sure the preload was ok... if the preload was too high wouldn't i have fretting on the left side of the hub also?
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Old 02-06-10, 08:02 PM   #23
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Just conjecture on my part. I think that the drive side bearings are under a bit more stress than the nondrive side due to the torsional forces of the chain drive. Over tightening or inadequate or incorrect grease can cause similar symptoms. Over tightening causes the bearing to "bottom" out on the race with not enough grease between the surfaces. Although these lubricants normally appear liquid (not solids), under high pressure they act as solids and keep the bearing and race from touching.

If the lubricant is removed, the bearings and races can touch directly. While bearings and races appear smooth to the eye, they are microscopically rough. Thus, high points of each surface can touch, but "valleys" do not. The bearing load is thus spread over much less area increasing the contact stress, causing pieces of each surface to break off or to become pressure-welded then break off when the bearing rolls on.

The broken-off pieces are also called wear debris. Wear debris is bad because it is relatively large compared to the surrounding surface finish and thus creates more regions of high contact stress. Worse, the steel in ordinary bearings can oxidize (rust), producing a more abrasive compound which accelerates wear.


They are shot, but as long as you load them up with lots of grease they should work till you replace them, but with some drag.
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Old 02-06-10, 09:04 PM   #24
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The chain tension is the highest load on the hub short of really big bumps. That suggests the problem is definitely too much bearing preload. The pitting which is evident on the rh cone is a fatigue failure stemming from an excessive load being applied and reapplied every time the bearings rolled over the races.

When you get a new hub or wheel, try testing the preload by clamping a stack of washers to each end of the hub with the quick release and adjust the skewer for proper closure to compensate for the slightly different thickness of the washers vs your dropout. You should feel solid contact but no drag. Then readjust skewer closure when you reinstall the wheel.
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Old 02-06-10, 09:09 PM   #25
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I just clamp it onto the outside of the drop-out to get the feel... though a stack of washers might be less awkward.
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