Sealed hub bearings: to replace or not to replace?
 

i'm posting this in C&V instead of mechanics because of the vintage nature of my project.

i'm rebuilding some older araya 27" rims on suzue sealed bearing hubs that came off my 1985 shogun tourer. i've never torn down a hub with sealed cartridge bearings before. i don't know if i should replace the bearings or not. since they're cartridge-type, i have no way of inspecting the ball races. after thorough degreasing and close inspection, they seem to spin smoothly and freely, and there was no noticeable dirt buildup-- the old semi-hardened grease looked clean. how can i determine if they should be replaced? and should there be slight resistance from the rubber seal? because there is no resistance with these. they spin almost *too* freely, in that i think the rubber would no longer function as a proper seal. also there is the slightest, almost imperceptible axial play between the inner and outer "casings" (not sure what you would call them since they're not cones and cups). since i have never handled a new cartridge bearing, i don't know how these things should feel. i can replace them easily enough (fronts are 6000RS and rears are 6200RS), but i'd rather not have to spend $20 for a set if these are perfectly fine.

Most sealed cartridge bearings can be serviced in a similar manner to conventional cup/cone bearings. If your hubs feel smooth all they should need is cleaning out of the old grease and regressing with some fresh grease.

<Disclaimer!: I'm not an expert on these by any means.>
Don't cartridge-bearing setups have nuts on the axle whose purpose is to establish some (adjustable) compression loading of the bearings? Seems to me that I've read that, here, or in Mechanics forum. The bearings themselves are not that expensive, assuming that you've got a standard size. Pressed-in, obviously, so one needs a puller to remove them, and quite possibly a press to install.

charles, i think you may be right. the outer casing press-fits into the hub (but is easily removed with a slight tap of the axle from the opposite side of the hub), while the inner "shaft" fits onto the axle. there is a compression adjusting ring with flats for standard cone wrenches to provide compression on the bearing. i assume the adjustment is performed the same way as for for older cup/cone setups.

as i said, the bearings are standard size, and are available online for about $3 a piece + shipping, so figure on $20 all said and done. i'm not overly concerned about the expense (even though this project has alread gone way over budget!), but i just don't want to throw away perfectly fine ones if i don't have to.

the thing that surprises me is that when i read the specs for this type of bearing online, it seems as though they are designed for much heavier duty than is ever seen on a bike! they are designed to withstand a load of almost 500lb each and are rated to 16,000 RPM! granted, this is for a full-loaded touring bike, but still...

I have never succeeded in cleaning out and regreasing a cartridge bearing without compromising the seals. Do you have a trick for that?

As the OP notes, these bearings are capable of handling a lot more load than they will see in bike use. However, most machinery that generates 16,000 rpm does not work in the weather and grit that a bike sees. Considering the relatively low cost, I would go with new units to insure good seals and protection from the elements. If the seals are truly intact, the grease should not even get hard with age because there is no way for the volatiles to escape.

"sealed" cartridge bearings are never truly 100% sealed, they have to allow gaps in the inner diameter of the seal/cone interface so an axle can spin. The grease injected in them does eventually degrade or get lost due to a number of factors, it just takes longer and they get far less intrusion from contaminants than conventional bearings...but it does happen. I've gotten seals off and cleaned/repacked cartridge bearings, but it's akin to micro-surgery, and very hard to do without crimping the seals and rendering them useless...I actually used a scalpel to pry the edge up...I'd only do it when there was no way to press out old and in new bearings in a unit. Some older ones have a very thin spring clip that holds the seal in place, these are easier to remove the seals from, but still not what I'd call "easy".

That's a good question, and I don't have an answer, either.

I recently replaced the spindle on my old Klein. It uses pressed in sealed bearings. I can confirm that new sealed bearings have some drag because of the seals. I think the drag is supposed to decrease after the break in period.

I replaced the bottom bracket bearings when I changed the spindles for two reasons. First, the force required to press the bearings out of the shell and remove the spindle is substantial. So there is a chance of damage. Second, the bearings were old and I don't really expect to do this again anytime soon. I didn't inspect the old bearings, but even after removal, they were smooth. BTW I bought Phil Wood bearings, which are supposed to be very high quality, for a little over $10 each and shipping.

Should you replace them? I don't think it's likely you'll experience catastrophic bearing failure. You may not even notice a difference with the new bearings. But if you decide to replace them, you'll be set for years.

Give me 30 minutes to write the tutorial.....

how does one compromise the seals by cleaning? these bearings have seals only on the exposed side, they are not double-sided sealed. i cleaned them from the inner, non-seal side and didn't perturb the outer seal by trying to remove it. the balls are clearly visible from the non-seal side. i probably wasn't able to get *all* the remnants of old grease this way, but between soaking in simple green and using a soft toothbrush, probably >95% got cleaned out. i'm curious why you think the seals get compromised this way... does the degreaser dry them out? i only soaked them for about 5-10 minutes before brushing, rinsing, and drying them. visibly they appear 100% intact.

unworthy1, i agree that the term "sealed" is a misnomer in this application. any two surfaces that experience dynamic friction are incompatible with *true* sealing, but they do a "good enough" job of keeping out 99.9% of the grit that would normally get into the bearings without the seal present.

I use an xacto knife to carefully lift the seals off. Clean out all the old grease, flush really well with brake cleaner or similar, repack with marine grease, put the seal back in and crack a beer and toast a job well done.:)

Let me start off by clarifying a few things about 'sealed cartridge' hubs:

'Sealed': For all intents and purposes sealed cartridge/sealed bearing hubs use sealed bearings. The bearings thenselves have seals to keep them clean. They are sealed. To call them anything other sealed would be a misnomer or akin to splitting hairs. A perfect seal that never allowed moisture in would have too much friction or would be too overly complex or cost prohibitive for a cycling application.

Inside/outside seals: Over the years I've repacked hundreds of selaed cartridge hubs. Every one of them has had seals on the inboard and outboard sides of the bearing. On the occasion when I'd replace a bearing it was always uni-directional, it didnt matter which side was facing in or out because both sides were sealed. The only cartridge bearing I've ever seen without seald on both sides was from an Olmo BB I disassembles a few weeks ago. It had a seal on the outboard side but was open on the inner side relying on the BB sleeve to keep everything clean.

Adjustment: Dont over think this. 'Play' with conventional bearing hubs is checked by rocking the axle 'up and down' or wiggling the tire between the chainstays. 'Play' with a cartridge bearing hub is checked by pressing the axle left to right or in and out.

Q/R compression: As a Q/R is clamped down everything is squeezed together on both conventional and cartridge hubs. I've noticed that conventional hub need much more 'play' to compensate Q/R compression whereas cartridge hubs need virtualy none.

Overhaul procedure:

Pic 1. The hub depicting the direction play is checked. Red/1 is for conventional hubs while Blue/2 is for cartridge bearing hubs.
Pic 2. Take it apart like any other hub.
Pic 3. Disassembly detail. If axle doesnt cone out easily tap it with something. A BFH works well.
Pic 4. Disassembly detail 2.
Pic 5. Removal of outer seal with a cutting blade. Always remove from the inside edge. Its nowhere near as bad as it looks. A screwdriver is too big and will damage the seal.
Pic 6. Opened up. This hub had been previously serviced.
Pic 7. Cleaning it up. I use a toothbrush and Dawn Direct Foaming dish detergent.
Pic 8. Nice and clean.
Pic 9. Greased up.
Pic 10. Seal back in place.

Pic 1
http://i.imgur.com/OcCewcq.jpg

Pic 2
http://i.imgur.com/6cSsrtW.jpg

Pic 3
http://i.imgur.com/1ZBjCxA.jpg

Pic 4
http://i.imgur.com/G9NpxF5.jpg

Pic 5
http://i.imgur.com/9sIin27.jpg

Pic 6
http://i.imgur.com/aMsdOF3.jpg

Pic 7
http://i.imgur.com/P7frpiu.jpg

Pic 8
http://i.imgur.com/KVRs07q.jpg


Pic 9
http://i.imgur.com/VjxYM8P.jpg

Pic 10
http://i.imgur.com/epWLsDp.jpg

^ he makes it look so easy! ;)^
Thanks for the great instructions, Jim!

I am probably just a klutz, but even prying the seal off with an xacto knife, I usually crimp it, which leaves it open to contamination.

So to summarize. The original question was: "Sealed hub bearings: to replace or not to replace?"

Some would say, You may damage them when you take them apart; you can never get them really clean because you can't dismantle them all the way; there may be wear in the bearing parts or the seals that you can not see; and replacement cartridges are cheap, so why not just replace them?

Others say, With a small amount of work, you can get a lot more life out them with no perceptible decrease in performance, and that can be pretty satisfying by itself. Even in the worst case, catastrophic failure is not a real risk.

So I guess the answer to your question is "Yes".

If it spins fine its probably okay. If it spins and has a little bearing noise that is common. I'd not worry at all. It's best to have a shop press in new bearings if they have the proper tools.

You can use the old socket method of pounding a new one in with the right size socket but its not as neat or fail proof as having the proper tools.

Great tutorial MiamiJim! There should be a way to tag such posts for a C&V Maintenance sticky.

It should be noted that the construction of sealed cartridge hubs that were OEM-ed by Sanshin (Suzue, Sunshine, Sansin, Sanshin, Suntour, Specialized) will share similar adjustable cone/axle design on one side.

OK, Jim, two questions:
1. I'm under the impression that
a) "sealed bearing" just means a cup-and-cone setup with some sort of wiping (rubber) seal, and
b) what you've pictured above, a bearing that can't have balls disassembled from races without destroying it, even though the seal may be removable, is a cartridge bearing.

Am I wrong about that? Is a cartridge bearing one where the seal can't be removed?

2. Do you dry out a hub that you clean that way completely before relubricating? Maybe in the oven at 130 degrees F (hard to do with a wheel, but a light bulb or careful heating with a hair dryer might help).

1a. 'Sealed bearing' could mean alot of things. Do sealed mechanisms like 'O' rings or labarynth seals fall under the 'sealed bearing' heading? I dont think they do. In my opinion the only type of sealed bearings are the ones pictured in this thread and that would be ones of the cartridge design. Everything else would be of the sealed mechanisn type and thus a pseudo sealed bearing.

1b. Correct. Whats pictured is this thread is a sealed cartridge bearing and in my opinion its the only true type of sealed bearing. In my opinion sealed bearing and catridge bearing are synonymous.

2. Yes, I dry the bearing out with compressed air but a hair dryer or would work equaly well.

okay, i went to the LBS and asked to see some new sealed cartridge bearings to compare with mine. after holding some new ones in my hand, spinning them, and checking for free-play, they feel essentially like my old ones. so, i'm sticking with my old ones!

i'm intrigued by all the comments about the cartridges being pressed in. all four of mine came out with no effort at all. one slid out when i pulled the axle out, and the other four popped right out with the slightest tap. if they came out so easily, why would the reverse not be just as easy?

The convention wisdom regarding conventional cup-and-cone bearings is to replace the balls with every second repack, because use turns the spheres into oblate spheroids. Does this advice hold for sealed bearings, as well?

It all depends on the tolerances of the new ones. They may or may not.


I've never heard that conventional wisdon but I'm going to say no, it doesnt apply.

Vintagers,
Consider this technique used in the dual sport motorcycle world for wheel bearings...remove the rubber seals, wipe out as much old grease as possible with toilet paper, do not use solvents or degreasers, wipe in new grease, reseal and adjust, ride.

Wheel bearings on my BMW are around 150K miles and running strong.The machine has been to the bottom of S.America(Tierra del Fuego) and Panama twice using ths technique. Regrease every 30K or so.
Same for the steering head. This works, is quick and easy.
bill

You have to be careful when dealing with hubs from the mid 80's and even into the 90's... manufacturers were trying to capitalize on the durability and ease of maintenance of the cartridge bearings that were becoming more common in upscale hubs. Many manufacturers labeled their hubs "Sealed Bearings" without making any distinction as to what "Sealed Bearings" meant exactly. With many hubs (even higher quality hubs in some cases) "Sealed Bearings" were nothing more than conventional cup-n-cone bearings with an outer cover pressed on.

It gets confusing, but with the OP's mid 80's hub I'd almost guarantee that his Sealed Bearings aren't cartridge... but a simple cup-n-cone set up with a seal popped on top to keep crap out.

another point with *cartridge sealed* bearing hubs: the outer race is usually a tight press-fit in the hub shell, and the axle is firmly held to the inner race by the friction of the so-called "cone" because that's what makes the rotating action taken completely by the ball bearings. If the cartridge pops out of the shell as easily as you say, I think the hub shell has worn to the point that the cartridge itself can spin...which defeats the principal. Your hubs may not be worth rebuilding if that's the case, and continued spinning will just make the wear worse. If you want to save them I'd try LocTite GREEN for the outer races/hub contact, if the wear is too much for that maybe an epoxy like JB Weld.

I know the 86 Cannondale SR500 used 'sealed' or 'cartridge' bearings and they are tight in the hub. Now I know how to lube them. Thanks MiamiJim

no, these are true cartridge bearings. as i said in my first post, they are standard 6000-RS and 6200-RS series, which defines them as cartridge bearings. there are no cups and cones. there is an inner bore and an outer bore with channel groves on the inside, on which the balls rotate. the balls hold the bores together and the assembly can not come apart. they look like this, but with a black seal, not blue:

http://www.vxb.com/ball-bearings-images/6200-2rs-6.jpg

unlike the newer cartridge bearings with seals on both sides, mine only have the seal on one side. that is how i was able to clean them without removing the seal.