Gearbox Bearings?

I have been looking around for bearings to pursue the potential Layshaft problem. Following on from "Oh That Gearbox" thread... In my experience "price" does not always promise quality and to me spending $100+ on a couple of g/box bearings is OK.......... But........... If i can save a $100 by buying Nashi or several other brands from jap manufactured bearings i will...
The postage to here in OZ can be between free (never from UK) and up to Au$60 from U.K. and U.S... Local Jap manufactured bearing are available @ approx $20ea, so that where i will buy..
Obviously there is an ongoing debate re "ball or roller", that i guess has been done to death... I'm going ball, cos the factory did, i dont know how "well" the casing has been machined, or distorted, or layshaft "out of round" etc. .... A ball bearing will ensure "alignment" for my application.. If somebody can talk me into roller bearings i am willing to listen

The main reason i've posted this thread is a question.......... All previous references to the above bearings on the other thread have used "Metric/Millimeters" for size quotes. Therefore were the gearboxes manufactures in Europe using Metric bearings ???... Why???

When i went to the local bearing supplier with the headstock/yoke bearings, i said can i have 2 of these and they are probably an "Imperial" size.. He went out back, came back with bearings and said "there Metric", So OK whatever...... Why ????

Therefore were the gearboxes manufactures in Europe using Metric bearings ???... Why???

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Europe is Metric and bigger than the UK so UK manufacturers could buy metric dimensioned bearings cheaper than imperial. Starting in the 50's BSA and Triumph went metric on wheel bearings and it progressively changed from there as new designs were drawn up, the AMC gearbox is older and the layshaft bearing is metric but it have have been a bush before a bearing was added.


The problem with the layshaft bearing is the cage breaking up not the balls failing, hence Mick Hemmings solution of a ball bearing with a different material cage.

I just rebuilt my gearbox and from memory, the sleeve gear bearing is imperial but the layshaft bearing ( drive side ) is metric!

I couldn't find a sleeve gear bearing from a bearing supplier so I got it from the bike shop. The layshaft bearing is easy to get but there are different cages. I would have preferred brass but ended up with a polyamide cage. It's OK with the usual heat of operation, but they don't like being overheated when you install them.

I go to my local guy for bearings.

For my gearboxes I use:

1654 2RS, LH Mainshaft
RLS-5 2RS, RH mainshaft
and I like the FAG NJ203E.TVP2.C3 for the layshaft.

Make sure to pull the seal out on the inside. of the mainshaft bearings.

All three bearings were less than $75.

" If i can save a $100 by buying Nashi or several other brands from jap manufactured bearings i will... "

you could likely save more by buying a CB 360 instead too .

They're still available here...

B+Bogus said:

They're still available here...

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Where's here?

they are still available in the uk but thats not much help to you in Oz if you dont want to pay the postage. But what is the cost of the gearbox failing at speed an locking the back wheel not only to your bank account but to your body if you come off ???

Hi B+Bogus,,

I find the shipping cost from the UK not all that bad,, Can you give me the address so that I can check it out ..

Cheers
Paul ... (New Zealand)

nznorton said:

Hi B+Bogus,,

I find the shipping cost from the UK not all that bad,, Can you give me the address so that I can check it out ..

Cheers
Paul ... (New Zealand)

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Me too so I can get it to the US. "They're still available here..." is a bit of a tease.

pete.v said:

B+Bogus said:

They're still available here...

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Where's here?

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I keep the exact bearing in the pic on hand in Australia.
http://norcomcycles.com/Gearbox.html

NorComCycles said:

I keep the exact bearing in the pic on hand in Australia.
http://norcomcycles.com/Gearbox.html

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PM sent.

NorComCycles said:

pete.v said:

B+Bogus said:

They're still available here...

I keep the exact bearing in the pic on hand in Australia.
http://norcomcycles.com/Gearbox.html

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I need a sanity check here - those pix show a FAG Made In Portugal. is that old stock? If so you end up reproducing the original problem. Its going to fail.

Jesus, just take the spec to a big bearing supplier and get the damn thing over the counter.

ML, here is some rumour poop.
Although the 6203 tb p6 c3 is somewhat classified as a Rotax aircraft bearing, I have heard from my supplier, a large one, that they have been reclassified and will now be made in Germany with the price multiplying.
Again, rumour.

ML said:

I need a sanity check here - those pix show a FAG Made In Portugal. is that old stock? If so you end up reproducing the original problem. Its going to fail.

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The FAG 6203 TB P63 bearings are made in Portugal-however this is a higher quality phenolic cage "TB" bearing and not the "old stock" brass cage 6203 bearing that failed, so there is no problem with this particular Portuguese-made item.

L.A.B. said:

ML said:

I need a sanity check here - those pix show a FAG Made In Portugal. is that old stock? If so you end up reproducing the original problem. Its going to fail.

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The FAG 6203 TB P63 bearings are made in Portugal-however this is a higher quality phenolic cage "TB" bearing and not the "old stock" brass cage 6203 bearing that failed, so there is no problem with this particular Portuguese-made item.

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To back up what Les is saying, the failure mode is not due to a poorly manufactured or designed bearing, but one which became under-specified for the job it was supposed to be doing.
I'm pretty sure they never failed on the Model 50 :wink:
I guess the failures would only generally have occured outside the warranty period, so the design would never have been reviewed (avoiding being cynical!).
GIven the safety-critical failure mode, this may be considered 'a bit of an oversight' :roll:

As with the superblend mains, a certain amount of flex needs to be accommodated due to the unsupported mainshaft & clutch, and the original bearing didn't allow for this - evidenced by the bearing cage falling apart (I guess being prised apart).
The phenolic cage allows for this, hence 'THE solution'.

I wonder if these bearings would fail if there was an outrigger bearing between the clutch and gearbox sprocket?