Early Commando Headstock Bearings

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maximini

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When you replace the loose headstock bearings with tapered bearings what do use at the bottom to keep the dirt out and the grease in? Also, do you need to do any special shimmimg? Thanks
 
The original early bearings were conical bearings, the balls were loose in a tapered holder, and you adjusted the looseness of the steering head by tightening or loosening the nut at the top of the bearings. Mine had annular thrust bearings which were in good shape so I re-used them and they had a felt washer in place of the standard metal or plastic sealed side. I found some on ebay for around $20 ea, but if you buy them from the auto store, they are expensive, around $50-60. There are covers for the bearings, so not much dust or dirt should get in there. If you use standard ball bearings, and you can get sealed bearings, you will need the spacer tube between the 2 bearings or you risk beating the bearings apart while riding, they are not meant to take the perpendicular forces. I bought some sealed ball bearings but never used them because of that. Don't ask me how to make that spacer, but it can be done, I think even if you buy one it may not fit right.

Dave
69S
 
I ALWAYS change out my headstock bearings with tapered rollers. Tapered roller bearings are THE way to go in the headstock, period ! The early type with ball bearings are marginal, and Norton really goofed when they put "sealed wheel bearings" type bearings in the headstock, and a spacer to boot ??? What a BAD joke, and wrong application of the bearing. And the spacer tube, throw it in the spare parts bin , as it's not needed with tapered rollers. You can make a "decent" seal for the bottom with a compass, some thin sheet plastic, or some rubber. (I use thin sheet plastic myself. ) Just measure and cut the disc the size you need, and install this in the bottom of the triple tree, thus protecting the bottom tapered roller from rain and dirt. You use the compass so you get precise concentric circles to cut, just take your time. Tighten the triple tree nut so it's snug, but you can still turn the forks from lock-to-lock freely. Works a treat !!!

The factory tapered roller headstock bearings are an area where Triumph got it very right on the T140s ... and Norton got it very wrong on the Commandos. Cheers ...
 
nortriubuell said:
I ALWAYS change out my headstock bearings with tapered rollers. Tapered roller bearings are THE way to go in the headstock, period ! The early type with ball bearings are marginal, and Norton really goofed when they put "sealed wheel bearings" type bearings in the headstock, and a spacer to boot ??? What a BAD joke, and wrong application of the bearing. And the spacer tube, throw it in the spare parts bin , as it's not needed with tapered rollers. You can make a "decent" seal for the bottom with a compass, some thin sheet plastic, or some rubber. (I use thin sheet plastic myself. ) Just measure and cut the disc the size you need, and install this in the bottom of the triple tree, thus protecting the bottom tapered roller from rain and dirt. You use the compass so you get precise concentric circles to cut, just take your time. Tighten the triple tree nut so it's snug, but you can still turn the forks from lock-to-lock freely. Works a treat !!!

The factory tapered roller headstock bearings are an area where Triumph got it very right on the T140s ... and Norton got it very wrong on the Commandos. Cheers ...
Click to expand...

Every experienced BMW dealer will disagree, having seen what happens to the average taper roller bearing in service in non-ideal, i.e. average conditions (ideal= fully greased, ideal play at all times, bike not standing in one position for long, otherwise the steering head bearing rollers dig into the tracks). Some engineering idiot in BMWs drawing office had a thing about taper rollers- even used them as wheel bearings on the Earles fork models.

Whilst the later Commando solution may look technically incorrect, it works fine and for many years. Which is why my son turned a spacer for his early Commando frame and used the later Commando "sealed wheel bearings" in the steering head. Advantages: no maintenance, trouble free, long life. Disadvantages: none. Now guess what Tigcraft's Supermono and Minimono racers use in their modern racing frame headstocks.... as do many other modern bikes.
 
I would not use tapered bearings on a Commando frame. They will work fine on BSA and Triumph frames were there is much more steel to support the side loads. Once the whole front end is built, and the forces from the road find their way up to the head stock tapered bearings will put some of that force into side loading the thin walled tubing through very thin contact points. Is it a pain to make a spacer that is just right for your frame? Yes it is hard to measure and than make with out a lathe. Is it worth the effort ...Yes IMO...
 
Well, didn't know that !!! I've installed tapered rollers in my pre-oif Triumphs, and any 650 Yamaha I've had as well. Thought it made sense (and have read it as well) about how Norton Commandos should have them too ??? Reading what I read, it made sense ... so that is why I changed to taper rollers.

Much sharper folks than me in this forum, that's why I read it so much. Gonna have to rethink this now. Never thought about the issue of the "weakness" of the thinwall tubing of the Norton, and the other stresses involved.
 
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