pivot bearing replacement

[brussel]

So I was doing some TLC to my Anthem x1. Relubing the fork, cleaning and relubing the shock. Then I felt the lower pivot....eeugh!

 

Where the axle goes through the shock there are two sets of small bearings (6802) back to back and then there is the larger 6902 on the rear triangle.

 

The two large bearings where a little under the weather, but not bad, I will replace them anyhow. The outer two small bearings where toast, could almost not turn them by hand.

 

just under 3000km of riding, no water or mud.

 

Sounds a little soon for my liking. What do you guys think??

 

Brent

 

[singletrackmind]

when you wash your bike water will get in there and just sit in their, think about that

[brussel]

 

fair enough but 3000km no mud or anything sounds heck of a short time to kill them. they RS spec so the rubber seals should keep (most of) the rubbish out???

brussel2009-02-05 13:03:59

[Goodbadugly]

The bigger problem of full suspension bikes. More maintenance. Sealed bearings are designed to go round and round and round... Thus lubricating themselves. In the suspension systems they move up and down. Sometimes just a millimeter or so. Lubrication does not occur. The grease is driven out. Soon it is metal on metal. And a visit to the bike shop/Bearing Man.

The bearings in my Anthem lasted 4000km.

Last week I replaced a bearing in the suspension of my Blur XC. Lifetime guarantee on bearings? Maybe. But it is much easier to buy them at Bearings International for R10 each than to wait for the claim. (These bearings had done less than 5000km's). 

Check and replace when necessary.

I have tried to extend the life of bearings with a drill.

1. Strip the suspension.

2. Get a dowel that fits snugly in the hole of the bearing.

3. Spin the bearing using the drill to "auto lube" it.

4. Refit the suspension.

Not sure it was worth the trouble.

If you train a lot, get a hard tail for that purpose. Less maintenance.

[Johan Bornman]

Cartridge (ball) bearings are inferior pivot points compared to bushes, just like  Badugly says.

 

I chuckle at his drill trick, just what the bearings need actually, but a pain to perform.

 

Those little seals on the bearings don't seal much. They're designed to leak a little bit of grease inside so that they can lubricate themselves, otherwise the seal will just burn away. We say a seal that doesn't leak, leaks. If it leaks grease out, it leaks water in.

 

 

[brussel]

 

Fair enough I do agree that bearings are inferior: but they are cheaper to produce so the manufacturers use them. But at ten rand a bearing it is not a train smash to replace them every 3000km.

 

Is there a great variety in quality of sealed bearings? Normally you can get some chinese thing for 10 bucks and then a NMB or SKF for 80 bucks...I cannot see in a low speed application how getting a more expensive bearing would make a difference?

 

It is not so much mission to replace them. I popped mine out in 20 minutes last night (add another 15 for machining some bits and bobs for the purpose)

 

Goodbadugly: another bike - hec it is expensive enough having one

 

Johan: wonder if one could retrofit bushings???

 

brussel2009-02-05 22:55:18

[jugheaddave]

I also firmly believe that bearings in Full Sys linkage is a bad idea. I have replaced my Anthem Bearings on several occasions.

 

Has anyone considered machining some bushes from vesconite, or aluminium to replace the bearings??

 

[brussel]

Jughead Dave. I have a lathe and mill machine. I could do some out of any material I can lay my hands on, it is though a little more complex than simply that I would think, radial forces would be fine, axial forces would need new thrust washers...any mech engineers to suggest why we could not do this??

 

[jugheaddave]

It would be an interesting thing to look into.

[Johan Bornman]

Fair enough I do agree that bearings are inferior: but they are cheaper to produce so the manufacturers use them. But at ten rand a bearing it is not a train smash to replace them every 3000km.

Is there a great variety in quality of sealed bearings? Normally you can get some chinese thing for 10 bucks and then a NMB or SKF for 80 bucks...I cannot see in a low speed application how getting a more expensive bearing would make a difference?

It is not so much mission to replace them. I popped mine out in 20 minutes last night (add another 15 for machining some bits and bobs for the purpose)

Goodbadugly: another bike - hec it is expensive enough having one

Johan: wonder if one could retrofit bushings???

 

Last night when I read your "R10 a bearing" comment I choked on my beer. I can smell a Chinese or Indian bearing a mile away. It smells like R10.

 

But this morning the foam has cleared from my nose and I think you have a point there. The expensive one will be no better in that application and won't last a minute longer, so why not buy Chinese bearings?

 

As you say, removing and replacing them is quick, especially once you've machined the necessary drifts.

 

The Vesconite solution will be better and it will be great if you do it yourself, for yourself. However, no-one will be prepared to pay you good money for what they'll perceive to be a downgrade. I suggest you make yourself a set of them and silently revel in the knowledge that your pivot maintenance is something of the past.

 

I think if you apply your mind to the design your lathe will go on autopilot and do the job chop chop.

 

 

 

 

[CaptainDura]

 

The Vesconite solution will be better and it will be great if you do it yourself' date=' for yourself. However, no-one will be prepared to pay you good money for what they'll perceive to be a downgrade. I suggest you make yourself a set of them and silently revel in the knowledge that your pivot maintenance is something of the past.

 

[/quote']

 

So these bushings, how long would they last compared to the bearings ?

 

I would be prepared to pay the R10 per bush instead of R10 for chinese bearings.

 

so lathe (or is that slave) away and get me some of those pronto. OK ?

 

 

 

[Johan Bornman]

 

So these bushings, how long would they last compared to the bearings ?

 

I would be prepared to pay the R10 per bush instead of R10 for chinese bearings.

 

so lathe (or is that slave) away and get me some of those pronto. OK ?

 

 

 

Probably 20 or 30 times as long if they're well designed. Like Brusselsprouts says, someone has to give the thrust washers some intelligent thought.

 

You want some bushes? Sure, it only means someone will have to get in his car, go and buy some vesconite in a suitable diameter. He mayhave to argue with the rep that even though he's just a small buyer, they should trade with him. Eventually he'll get it at retail plus 30%.

 

Second problem then rears its head. Vesconite sells by the 6m piece. No problem, he as a station wagon. He then has to saw this in half, get the lot in his car and go home. After supper he has to take one of his suspension bearings out, carefully measure all the diameters and thicknesses of the various bearing shells and re-do the bearing in vesconite. One pivot, one outer and two thrust washers.

That same sucker then has to go out and find a suitable smooth-shaft bolt, in stainless nogal to go through the pivot.

 

He will then test it, get it dirty and see of the thrust washers are doing their job. Only then will he carefully copy the bushes and make as few, one at a time. All the time checking with his vernier that the tolerances are just right.

 

Then when all that's done you want to give him ten bucks for the job.

 

Suddenly DSTV repeats are very attractive.

 

Second disclaimer, I dont have a lathe and I'm not clever enough to operate one. Maybe Brusselsprouts will do the job for you. I'll take a small commission for the referral. I mean, there's lots of margin in there.

 

 

 

 

[Mellow]

...i also want something.... sommer for reading all the k@k JB just wrote.

 

would be great though if someone try this

 

[brussel]

you guys are full of c@#p!!!

 

 

Johann is right, it is a lot of work, although I have a friend who has a prescision engineering firm that has huge CNC lathes...if they work we could get him to make some up.

 

BUT

 

the problem is that the 6802 bearings in some fo the pivots are only 4mm wide that is not a lot of surface area for a plastic bushing, but it can be done. So I promise I will give it some thought....but I don;t think they would be R10 a piece....

 

incedentally I bought bearings today ...whole lower pivot (6 bearings) for R102 rand, means that really other than the hour it takes to replace them  it is not a major cost to do every 3000km.

 

[Goodbadugly]

One of the problems of a bushing is that it also (in time) eats away on the axle. The wear is not confined to the bushing. If you go for the bush-option, make sure you use top quality stainless steel axles. The aluminum used in some standard axles just won't last. Especially if it comes into contact with sand/dirt.

Using a bearing confines the wear to a nondescript chinese bearing. I think I will stay with el cheapo bearings. 

[CaptainDura]

the problem is that the 6802 bearings in some fo the pivots are only 4mm wide that is not a lot of surface area for a plastic bushing' date=' but it can be done. So I promise I will give it some thought....but I don;t think they would be R10 a piece....

incedentally I bought bearings today ...whole lower pivot (6 bearings) for R102 rand, means that really other than the hour it takes to replace them  it is not a major cost to do every 3000km.
[/quote']

 

thanks Brussel.

 

I think for R102 it is very plausible to replace every 2000 or 3000 k's.

 

If at all possible could you give me the bearing numbers i need to purchase and the amount of each. is see you mention  6802 bearings

 

also where did you buy those bearings ?

 

i am going to buy me a spare set to take on the epic so i have backup if i need it.