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Old 2005-02-26, 05:02 PM   #1
karl-the-frogman
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Unhappy moving my bearing

I have a bearing pretty close to the inside, on my hub. It causes my other bearing to push out and into my cranks as I ride.
Is there a way to move the bearing out safely? Can I apply some oil or something? Do I need a tool to do the job? Is my other bearing supposed to move like that anyway?
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Old 2005-02-26, 05:06 PM   #2
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I am so confused how does a bearin get pushed out there should only be one set of bearings on each side
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Old 2005-02-26, 10:26 PM   #3
john_childs
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It's not uncommon for a bearing to get loose and slip on the axle like that. The bearings are just press fit on the axle. The only thing keeping them in place is the friction of the press fit. If that press fit gets loose then the bearing will slip and move closer to the crank.

The solution is to use Loctite Sleeve Retainer to secure the bearing on the axle. The Loctite "glues" the bearing in place so it won't slip. You can get Loctite High Strength Sleeve Retainer at auto parts stores. The part number will start with 640. Permatex is another brand that is pretty much the same stuff as Loctite. Either will work fine.

The steps:

Remove your crank

Pull off the bad bearing. If it is really loose you may be able to pull it off by hand, but most likely you'll have to use some sort of bearing puller. Unicycle.com sells a bearing puller. You can also get the same thing at an auto parts store. These pullers are designed to pull off pulleys and gears from cars.

Clean the grease and dirt from the bearing and the axle. The parts need to be clean for the Loctite to get a good bond. You can use some sort of degreaser (like Simple Green) to clean off the grease and oil.

Put some Loctite on the axle where the bearing will go. Put some Loctite on the inside race of the bearing.

Press the bearing on by hand to get it started. Then use a small piece of pipe to press the bearing on the rest of the way. You can use a mallet to pound on the pipe to get the bearing on. You want a pipe that is just big enough to fit over the axle yet small enough that it isn't bigger than the inside race of the bearing. When you press the bearing on you want to be putting force on the inside race of the bearing and not on the bearing seal. If you press on the bearing seal you can (and likely will) damage the bearing so that it won't spin well once you get it pressed on. I have found that a spare section of a 22.2 mm Miyata seatpost works well. Some electrical conduit is also about the right size. You may have to look around for the ideal size pipe.

Put the crank back on.

Let the Loctite cure for about 6 hours then go ride.

If you don't have the tools necessary then you can have a bike shop do it. Most bike shops should have a tool that can be used as a bearing puller. Or you may be able to borrow a bearing puller from someone who does auto work.
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Old 2005-02-27, 05:23 PM   #4
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Has anyone ever used some kind of sleeve or washer between the hub and the bearings to eliminate this problem completely. A sleeve could be a piece of tubing cut to the right length so that the bearings stay at the correct distance from the hub. It could be plastic or metal tubing.

I imagine that you'd want to put grease on the axle before sliding the sleeve on to eliminate any possibility of water collecting between the sleeve and axle to keep rust from forming.
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Last edited by One on one; 2005-02-27 at 05:29 PM.
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Old 2005-02-27, 05:42 PM   #5
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Quote:
Originally posted by One on one
Has anyone ever used some kind of sleeve or washer between the hub and the bearings to eliminate this problem completely. A sleeve could be a piece of tubing cut to the right length so that the bearings stay at the correct distance from the hub. It could be plastic or metal tubing.

I think Torker did that with my DX.
(by the look of it .. don't know for sure, cuz I haven't taken it apart yet)

I bet Jagur would know ...
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Old 2005-02-28, 01:23 AM   #6
john_childs
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Quote:
Originally posted by One on one
Has anyone ever used some kind of sleeve or washer between the hub and the bearings to eliminate this problem completely. A sleeve could be a piece of tubing cut to the right length so that the bearings stay at the correct distance from the hub. It could be plastic or metal tubing.

I imagine that you'd want to put grease on the axle before sliding the sleeve on to eliminate any possibility of water collecting between the sleeve and axle to keep rust from forming.
That's the way that the current splined hubs work (like Profile and KH and Torker) except for the French hub that uses the ISIS splines.

That wouldn't work well for standard square tapered cranks. One problem is that different cranks slip on the axle a different distance so you'd need a custom spacer for each brand of cranks combined with each brand of hub. And then that design would tend to push the crank off the axle which is exactly not the thing that you want to have happen with a square taper setup. Not a good idea for standard hubs. The Loctite solution works well enough.
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Old 2005-02-28, 01:30 AM   #7
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Quote:
Originally posted by john_childs
That's the way that the current splined hubs work (like Profile and KH and Torker) except for the French hub that uses the ISIS splines.

That wouldn't work well for standard square tapered cranks. One problem is that different cranks slip on the axle a different distance so you'd need a custom spacer for each brand of cranks combined with each brand of hub. And then that design would tend to push the crank off the axle which is exactly not the thing that you want to have happen with a square taper setup. Not a good idea for standard hubs. The Loctite solution works well enough.
Wouldn't that only be the case if the washer / sleeve were placed on the outside of the bearing.
If it was placed on the inside between the bearing and the hub, there wouldn't be any pressure on the cranks because any pressure would be between the bearing and the hub. There would be very little movement because everything would be sandwiched between the bearing holders.
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Old 2005-02-28, 02:16 AM   #8
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Quote:
Originally posted by One on one
Wouldn't that only be the case if the washer / sleeve were placed on the outside of the bearing.
If it was placed on the inside between the bearing and the hub, there wouldn't be any pressure on the cranks because any pressure would be between the bearing and the hub. There would be very little movement because everything would be sandwiched between the bearing holders.
That is the way that it is currently done on the square taper hubs. There is either a slip on sleeve or a machined lip that acts as a physical stop for the bearing when it's pressed on. But that only stops the bearing from moving too far towards the hub. It doesn't stop the bearing from moving towards the crank.

Very few frames are stiff enough to hold a loose bearing in place, and those that are stiff enough are overbuilt. You can't rely on the frame to keep a loose bearing in place.
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Old 2005-02-28, 04:44 AM   #9
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Quote:
Originally posted by john_childs
That is the way that it is currently done on the square taper hubs. There is either a slip on sleeve or a machined lip that acts as a physical stop for the bearing when it's pressed on. But that only stops the bearing from moving too far towards the hub. It doesn't stop the bearing from moving towards the crank.

Very few frames are stiff enough to hold a loose bearing in place, and those that are stiff enough are overbuilt. You can't rely on the frame to keep a loose bearing in place.
So what you are saying is that the frame ends up flexing apart wider because of pressure from the bearing.

In my line of work, we use bearings that have a set screw to hold the bearing in place on the shaft. Is there a bearing manufactured that is the correct size for the uni, that also would have a setscrew to lock it onto the shaft? Has anyone ever looked into that?
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Old 2005-02-28, 06:28 AM   #10
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Quote:
Originally posted by One on one
So what you are saying is that the frame ends up flexing apart wider because of pressure from the bearing.

In my line of work, we use bearings that have a set screw to hold the bearing in place on the shaft. Is there a bearing manufactured that is the correct size for the uni, that also would have a setscrew to lock it onto the shaft? Has anyone ever looked into that?
Yup. The frame legs flex apart due to the slipping bearing. The bearing gets the outward force do to pedaling forces. There is more outward force on the bearing when climbing hard or pedaling hard.

I'm not familiar with the type of bearing you describe. I can't say whether that type of bearing would work or not.

The Loctite fix does solve the problem. Two of my unicycles have had a slipped bearing. The first was my stock Coker and the second was my DM freestyle uni. Loctite solved the problem and the slipping hasn't reoccurred.

Unfortunately, when you buy a new uni it's not going to come with the bearings Loctited on the hub. That's unfortunate.
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Old 2005-02-28, 08:41 PM   #11
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<magically returns from the wilderness>

Similar problem:

The bearings on this 'ere 29er are utterly knackered to the point that turning the wheel is difficult and makes horrific grinding noises. These are the bearings that have coped with torrential rain, red-bull quality mud, a trip into a canal and submersion in many a muddy puddle on the Quantocks, so I think they've had a good innings.

Only... I can't get them off the hub, a unicycle.com wide cro-mo specimen.

The first I eventually managed to remove, but it destroyed the bearing puller in the process. I can't get the other one off. Neither can two local bike shops, or a large hammer and a screwdriver poked through the holes in the hub flange. A larger bearing puller won't fit between the bearing and the flange. The flange also gets in the way of attacking the bearing with a hacksaw.

What's left? I don't really want to replace the entire hub and rebuild the wheel just to replace some bearings, but I'm out of ideas.

Help...

Phil
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Old 2005-02-28, 08:53 PM   #12
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Hydraulic press.

Find a machine shop.

Although, they may tell you to remove the hub from the wheel first.
(unless they have sort if rig to 'pull press' the bearing)

Did you try heating the bearing with a torch..?
(heat expands metal)

Then maybe apply some light oil to seep into the area while it's hot.
(that's gonna smell bad)
Then try the bearing puller again.
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Old 2005-02-28, 09:08 PM   #13
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Quote:
Originally posted by phil
<magically returns from the wilderness>
What's left? I don't really want to replace the entire hub and rebuild the wheel just to replace some bearings, but I'm out of ideas.
If it's that bad, can't you just Dremel it off? I'm going to be replacing my bearings soon too. I hope I don't run into the same problems.
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Old 2005-03-01, 10:52 AM   #14
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Quote:
Originally posted by phil
<magically returns from the wilderness>
The first I eventually managed to remove, but it destroyed the bearing puller in the process. I can't get the other one off. Neither can two local bike shops, or a large hammer and a screwdriver poked through the holes in the hub flange. A larger bearing puller won't fit between the bearing and the flange. The flange also gets in the way of attacking the bearing with a hacksaw.
If you're up this way any point soon, I've got the Bearing Puller of Doom that would probably do it.

http://www.machinemart.co.uk/product.asp?p=040210249

If you can find a car garage that has a combined bearing separator + puller that's what it is and it works well (at least with suzue hubs it does). A bit slow as you have to bolt on the separator nice and tight, then fit the puller then do the actual removing, but pretty heavy duty.

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Old 2005-03-01, 06:15 PM   #15
phil
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Quote:
Originally posted by joemarshall
If you're up this way any point soon, I've got the Bearing Puller of Doom that would probably do it.
I dunno, it was something very similar that made the ultimate sacrifice for the first bearing. The two bolts of the bearing separator are now an interesting curvy shape.

On the other hand my puller and separator cost an awful lot less than £35, so maybe they just weren't up to the job.

I think attacking it with a dremel may be the best way forward. I've always wanted an excuse to own one of those...

Phil
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