SleeveGear Needle Bearings

I have seen a picture of a sleeve gear with a needle bearings. Without stealing from the RGM web site of the close ratio gearset picture (this is probable flagrant enough), I hope this would be simple to identify.
Oh, what the heck,


I know my mainshaft is worn a bit in this area and should be replaced.

Has anyone done this to there own sleeve gear? I believe I could spec out the size of the bearing but I am concerned about the load and grade of the bearing to accommodate this function.

Machining the bores are not an issue for me unless i screw it up, of course.

Wow now that's a great idea for those running in lower gears very much at very much rpm and throttle. The area sits below oil level so it drains out at rest and it slings oil out in lower gears, so about only time sleeve gears get splashes and not preventing dry running it while in top 1:1 ratio. Before i understood this lube lack issue Peel turned her sleeve bush interface into hardened bronze/steel/carbon cermaic grit with worn shaft dia. I was talked out of needle bearings in cam ends d/t the cam surface hardening issue. This is my area of concern even with the TTIgearbox. Hope you figure it out so rest of us can follow you or avoid your bad discoveries.

I did this on a worn out gear as a test, the needle bearing is a std one and I will look out the size tomorrow. I used a reamer on a lathe but the lead in taper was off so the hole was too, should have used a boring tool on the saddle and finished off the last couple of thou with the reamer. The bearing is the narrowest one in the catalogue or you risk weakening the gear.

I wouldn't waste your money. RGM did mine several years ago in an attempt to stop the flailing kickstart (its not just duff layshaft bearings that make it do that). They overmachined the shaft (lengthwise) so the sleeve gear bush is only running on 70% of the correct diameter. I eventually fixed the problem but I don't believe the needle conversion does an awful lot.

kommando said:

I did this on a worn out gear as a test, the needle bearing is a std one and I will look out the size tomorrow. I used a reamer on a lathe but the lead in taper was off so the hole was too, should have used a boring tool on the saddle and finished off the last couple of thou with the reamer. The bearing is the narrowest one in the catalogue or you risk weakening the gear.

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Was this done on the gear side only? There doesn't appear to be much meat on the sleeve side.

Gear side only, my plan was to leave the bush in place for the rest of the gear as there is too little meat and one bearing at the end where the bending forces are greatest should be enough.

Nova Racing makes a 6-speed gearset for the AMC boxes that uses a needle roller bearing in the sleeve gear, so there's at least some evidence that it works. I believe some of the newer Quaife boxes use rollers in the sleeve gear, but I haven't been able to find any references to verify it. All the Quaifes I've used have had bushings. I'm not sure what benefit rollers would offer here. As hobot mentioned, the mainshaft is not as hard as normal bearing race material, but I don't know if that would really cause a problem. Unless you can support the outer end of the sleeve gear, like with a good outrigger bearing design, the stock bronze bushes might work better than rollers. I'd worry about the rollers digging into the mainshaft as it flexes. The issue with the sleeve gear is that it doesn't have enough bearing support length in the case to stop it from moving as the mainshaft flexes. Norton addressed this issue on their F750 racers by using an extended length sleeve gear that accommodated an outrigger bearing in their custom inner primary cover. Not sure how they managed the primary chain adjustment with that. I saw the original drawing for the extended sleeve gear years ago in Norman White's shop, but don't recall all the details.

Ken

its been some years since last inside AMC box so forget the turning directions of the main/bush/sleeve shafts but when I do I will have hole drilled in at a tangent so the spinning tends to pump spray/splash inward rather than outward as most my fun on Commando is the lower gear, especially 2nd for mile and miles of rpm's and rpms. Main benefit of more stable main shaft would be in belt drives keepping alignment longer.

lcrken said:

Unless you can support the outer end of the sleeve gear, like with a good outrigger bearing design, the stock bronze bushes might work better than rollers. I'd worry about the rollers digging into the mainshaft as it flexes.
Ken

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My take on this is a solution hunting for a problem or more like trying to turn a sow's ear into a silk purse. Just does not appear to be much to work with between the main shaft diameter, robustness and size of the sleeve gear and the cantilevered loads on the man shaft. Just a tough situation. The motor evolved but the gear box did not. One work around is speeding up the gear box but that has it's own shortcomings.

Anyone around for comments on the performance (longevity) of the RGM style conversion?

As for premature sleeve gear bushing wear, I wonder if the more modern synthetics would help?

Dances with Shrapnel said:

My take on this is a solution hunting for a problem or more like trying to turn a sow's ear into a silk purse.

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I am beginning to feel that way myself. A good shaft, fresh bushing and TLC andI should be good to go for a good long time.

Dances with Shrapnel wrote:
My take on this is a solution hunting for a problem or more like trying to turn a sow's ear into a silk purse.

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Exactly right, I got taken in

Keith1069 said:

Dances with Shrapnel wrote:
My take on this is a solution hunting for a problem or more like trying to turn a sow's ear into a silk purse.

Click to expand...

Exactly right, I got taken in

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You may also find that the needle rollers do not like to be loaded while not rotating in 4th gear

I am working on a 1979 Triumph that has a resident 5 speed Quaif gear set where the sleeve gear has two sets of self contained roller bearings; oil-lite bronze bushings everywhere else. I assume that this configuration was designed to get the Triumph well off the warantee period, but more expensive (in manufacturing ??) than a pair of bronze bushes, so what else could their motivation be than to increase reliability??

Bill.

RoadScholar said:

I am working on a 1979 Triumph that has a resident 5 speed Quaif gear set where the sleeve gear has two sets of self contained roller bearings; oil-lite bronze bushings everywhere else. I assume that this configuration was designed to get the Triumph well off the warantee period, but more expensive (in manufacturing ??) than a pair of bronze bushes, so what else could their motivation be than to increase reliability??

Bill.

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The key word is "designed".

What you have was designed to perform with rollers whereas the AMC box with the subject roller (needle) bearing conversion is not. See Ken's notes above.

Bill.[/quote]

The key word is "designed".

What you have was designed to perform with rollers whereas the AMC box with the subject roller (needle) bearing conversion is not. See Ken's notes above.[/quote]

I don't see a lot of difference between the main shaft designs of the Norton and the Triumph, nor the distances between the sleeve gear case based (caged ball--Norton, or the roller Triumph) bearings and the clutch baskets, both designs ask a lot of the main shaft in terms of radial stability, one truns on bronz one swings on needle rollers. Did the Triumph get the next generation bearing set or did the Norton get what it needed?

Bill.

Well conceptually, needle bearings in an AMC gear box is a good idea. From what I can see of the gear box there's not much there to work with. I have only come across one modification worth doing but it eliminates the kick starter so what good is that.

In the case of your Triumph there are things that may not be readily apparent to you such as exact bending moments and surface hardness to accomodate rolling elements. Furthermore, I do not recall hearing about Triumphs needing outrigger bearings whereas with the Norton AMC boxes in race applications it is legendary.

So from a conceptual stand point why not make the changes in an AMC box since they do it in a similar Triumph box but the devil is in the details. So again, the key term is "design". We are at a conceptual level here.

If you have the opportunity to see the workings of a TTIndustries box you will see design, and engineering with the only real constraint being that it must fit into the AMC box "look"; otherwise I would call it starting with a clean slate. Rollers and needles are used quite a bit in the TTIndustries box.

lcrken said:

I believe some of the newer Quaife boxes use rollers in the sleeve gear, but I haven't been able to find any references to verify it.
Ken

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Ken - you're correct. I have a 6 speed Quaife 'box in my Seeley G50 and the mainshaft runs in two pairs of split needle roller bearings. It seems to work well. Last time I took it apart, there was no evidence of the rollers digging in, but maybe the shaft and gear are harder than the equivalent Norton parts? There is less overhang on the mainshaft compared to the Commando, which I guess is also a factor to consider. I would not claim that needle rollers are superior to the bronze bushes, because I have no evidence, but they are easier to replace!

The sleeve gear itself runs in two narrow ball races separated by a spacer. I have not checked to see if the effective bearing width is wider than the standard single AMC bearing but it looks as if it isn't. If it is the same, why would Quaife have done this?

Pvisseriii - I think that the standard bronze bushes in the sleeve gear are adequate for the job on a standard Commando.

Dave

daveh said:

[Pvisseriii - I think that the standard bronze bushes in the sleeve gear are adequate for the job on a standard Commando.

Dave

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Thanks daveh and others. I don't htink I would venture into applying a needle bearing without a rockwell reading of mid 50's on that area of the shaft. I have seen how the shaft wears under a bushing, that is why I need a replacement. Maybe when i get the new one I will check it just for grins. I doubt I would see those numbers. More like mid forties.

daveh said:

The sleeve gear itself runs in two narrow ball races separated by a spacer. I have not checked to see if the effective bearing width is wider than the standard single AMC bearing but it looks as if it isn't. If it is the same, why would Quaife have done this?

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My guess is angular stiffness. A single row ball bearing has a certain allowable angular misalignment; you put two side by side and the shaft angular misalignment is more constrained or inhibited.

or

Maybe using two rows of rollers allows the use of smaller diameter balls which allow a larger diameter sleeve gear sleeve. Never messed with a quaif so I do not know.

Again, just a hunch.

Thanks daveh and others. I don't htink I would venture into applying a needle bearing without a rockwell reading of mid 50's on that area of the shaft. I have seen how the shaft wears under a bushing

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I had my gearbox apart before Christmas, looking for source of odd noises etc and the RGM ground shaft is perfect, no wear at all and that's with maybe 18,000 miles on it but most of my riding is done at speed in top gear. I wonder how much it does turn in the lower gears and presumably it rotates a little in top. I guess the heavy loads of kick starting give it the hardest treatment ?