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Sorry, I don't understand this expression «Steering head taper roller bearing» 
Is the «stearing head bearing» meant?
Fritz
Is the «stearing head bearing» meant?Fritz
Steering head taper roller bearing
- Thread starter bad_friday
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I noticed front end juddering under braking on my '72, I discovered that the manual said it was sealed ball bearings. Is it a worth while mod to go to taper rollers or is that like starting an oil thread.....?
I thought ball steering a thing of the past but my Thruxton apparently has them and my mate says his Ducati sports classic too...cheaper??? or quicker steering???
I thought ball steering a thing of the past but my Thruxton apparently has them and my mate says his Ducati sports classic too...cheaper??? or quicker steering???
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+1 with what Brent writes. And, I also ... ONLY run tapered roller bearings in my bikes. Cheers.
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The taper bearings that I installed on my 1970 (I think that they were purchased from British Spares in NZ - so will be one of the usual brands sold for Nortons) sat direct on the bearing lip inside the steering head, but were slightly wider (in depth not diameter) than the original roller set up, with the consequence that the top of the steering head now sits slightly higher, and the security lock on the steering head is now just an ornament, as it no longer catches on the bar on the outside of the steering head that stops the steering head from turning when the lock is engaged. i think that later models have a different method of holding the bearing, so that might not be an issue for them.
bad_friday said:Sorry, I don't understand this expression «Steering head taper roller bearing»
A taper(ed) roller bearing is a Kegelrollenlager in your language and Wikipedia has an article about it.
IMHO replacing the 6205 ball bearings on post-1970 frames (with 30205 TRBs) isn't as straightforward as some apparently handle it - to do it correctly there needs to be a spacer around the stem which needs to be very precise in length, we're talking about a few microns here. Otherwise the clamping force will exceed a sound pre-load level or in other words the spacer in this kind of setup will act like a spring so that a sound clamping force will compress said spacer just so much that it will end up in the correct pre-load. Plus the 30205 are 1.25mm longer than the 6205 so the overall setup is 2.5mm longer. I run this in my Atlas but will replace the TRB with Angular Contact Roller Bearings (7205 to be precise) as these share the cross section with the 6205. On the old Atlas/Early-Commando head stock the ACRBs or TRBs can be run without a spacer as the pre-load is "dialed in" with the nut underneath the upper yoke and the whole setup is then correctly clamped by the yoke and the nut above it (however a correct spacer is still the superior solution).
Just my €0.02.
Tim
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Tintin said:bad_friday said:Sorry, I don't understand this expression «Steering head taper roller bearing»
A taper(ed) roller bearing is a Kegelrollenlager in your language and Wikipedia has an article about it.
IMHO replacing the 6205 ball bearings on post-1970 frames (with 30205 TRBs) isn't as straightforward as some apparently handle it - to do it correctly there needs to be a spacer around the stem which needs to be very precise in length, we're talking about a few microns here. Otherwise the clamping force will exceed a sound pre-load level or in other words the spacer in this kind of setup will act like a spring so that a sound clamping force will compress said spacer just so much that it will end up in the correct pre-load. Plus the 30205 are 1.25mm longer than the 6205 so the overall setup is 2.5mm longer. I run this in my Atlas but will replace the TRB with Angular Contact Roller Bearings (7205 to be precise) as these share the cross section with the 6205. On the old Atlas/Early-Commando head stock the ACRBs or TRBs can be run without a spacer as the pre-load is "dialed in" with the nut underneath the upper yoke and the whole setup is then correctly clamped by the yoke and the nut above it (however a correct spacer is still the superior solution).
Just my €0.02.
Tim
++ Jim
6205 2 RS ball bearings are okay for general street riding. If you don't want to go to all the trouble of setting up the tapered bearings properly. The 7205 bearings sound interesting, but I think these are difficult to obtain with integral seals, so added complications here I would think?
Cheers Richard
Cheers Richard
stockie2 said:
7205-2RS are at least featured in the FAG/INA catalogue so they should be relatively easy to source for a good vendor - it might take a few days though.
BTW: Don't be mistaken though, what I said about the spacer for the TRBs is valid for the ACRBs as well, kinematically they are very similar and need identical setups for preload.
Tim
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I almost skipped this post as can't for the life of me imagine what advantage the tapper has over intact plain bearings clamped properly with correct spacer length making them act as one. I very much know what a stiff set of stem bearings does to handling feel, but that's a rust up wear out issue not basic geometry. So i really want to know why these tappered ones are considered an upgrade? To get a spacer finished to the micron level sounds pretty intense trial error fit what with Norton variation and need to preload just right.
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The advantages of a sealed ball bearing.
1. They are sealed and can survive a rainstorm or maybe even a pressure wash without having to worry about rusty balls.
2. Ball bearings are low friction and help maintain the light handling feel Nortons are known for. Adding friction here contributes to weave. The fact that Norton steering head tubes are often out of round makes for additional problems with setting preload with tapered rollers.
When I converted my racebike to tapered roller bearings [just because it was the thing to do] the bike felt noticeably heavier and I went back to ball bearings.
3. They don't require an accurate spacer and/or shims to set preload. Just a spacer of approximate length will allow the stem bolt to be torqued and keep the triple clamp assembly rigid.
Advantages of a tapered roller bearing
1. They would be more likely to survive a high speed crash and still be usable. [hobot- you need these]
seriously- if higher strength is needed for off road racing I would consider the angular contact ball bearing and not the tapered roller. Jim
1. They are sealed and can survive a rainstorm or maybe even a pressure wash without having to worry about rusty balls.
2. Ball bearings are low friction and help maintain the light handling feel Nortons are known for. Adding friction here contributes to weave. The fact that Norton steering head tubes are often out of round makes for additional problems with setting preload with tapered rollers.
When I converted my racebike to tapered roller bearings [just because it was the thing to do] the bike felt noticeably heavier and I went back to ball bearings.
3. They don't require an accurate spacer and/or shims to set preload. Just a spacer of approximate length will allow the stem bolt to be torqued and keep the triple clamp assembly rigid.
Advantages of a tapered roller bearing
1. They would be more likely to survive a high speed crash and still be usable. [hobot- you need these]
seriously- if higher strength is needed for off road racing I would consider the angular contact ball bearing and not the tapered roller. Jim
hobot said:
DeepGrooveRollerBearings are not really [tm] designed to take hefty axial loads and this is what they are subjected to in a head stock. Show the DGRB solution to a roller bearing specialist and he'll be running away crying, swearing, shouting, whatever. The only justification for DGRB in a headstock is the price and the fact that they actually work. It's a classic example of one solution being "sufficient" vs. the other one being "superior".
They don't "act as one" but I regard this as the inevtitable Hobotism in this post. ;-)
Tim
comnoz said:
That is exactly the point - the effort needed to do this correctly would make the costs explode. The ACRBs are a nice alternative but honestly they are obviously not necessary. However doing it right has a certain magix in itself .... :mrgreen:
Tim
I believe that setting up tapered head bearings on the Norton stem would be closely resembling the set up of the wheel bearings on BMW /7 models. Not a simple & quick task. You would need to machine 2 bottom stem nuts so when torqued to say 25 ft lbs, they would not work loose. A center distance tube would have to be machined to locate on the roller portion inner race---less maybe .100~.200". This smaller distance would be the shimming space. Trial and error would have to determine the shim thickness needed so when the complete assembly was torqued to 25 ft lbs there would still be a nice push fit of the shim which would be the approximate preload on the bearings.
As time and mileage goes by---this would have to re-shimmed again to take up the wear/slop. BMW uses a kit with various thicknesses of shim stock that makes this easy.
You would have to make new shim pieces again and again to maintain the preload adjustments. Or, maybe with some investigative work, find some suitable shim stock to use---stacking these to get the correct preload.
You could of coarse just not use this shimming assembly and just put the bearings in and adjust the preload by the amount of torque on the bottom stem nut, but the bearings would slam into the races as you go down the road--nothing to keep the center rollers at a set preload on the races.
The question is----what is the objective of installing the tapered bearings.
As time and mileage goes by---this would have to re-shimmed again to take up the wear/slop. BMW uses a kit with various thicknesses of shim stock that makes this easy.
You would have to make new shim pieces again and again to maintain the preload adjustments. Or, maybe with some investigative work, find some suitable shim stock to use---stacking these to get the correct preload.
You could of coarse just not use this shimming assembly and just put the bearings in and adjust the preload by the amount of torque on the bottom stem nut, but the bearings would slam into the races as you go down the road--nothing to keep the center rollers at a set preload on the races.
The question is----what is the objective of installing the tapered bearings.
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A bit confused now as didn't know I needed to upgrade beyond what Norton designed to take on roots and rocks and ledges and some landings. IIRC Peel has sealed balls in stem and turns too easy by gravity if I get them off center balance with bike up on a milk crate. i'm familiar with bicycle cones in wheels to set bearing clearance/drag, but sure don't want that in my stem. If I do injure the bearings and don't wrap forks into my knees or back of skull, then just renew em and go use em up again.
hobot said:
YES, that would be the easy road taken----depending on wear--maybe every 2 years or so.
i would still use a double nut on the bottom stem---torque untill the forks just drop by their own weight--from center to left/right---you should be ok. That's how I have mine. Keep well greased---make some type of seal for the ends to keep water and dust out---use your imagination. Also---place a large flat washer on the inner race so the yokes will have some purchase on the inner bearing races. Don't forget to loosen the bottom pinch bolts on the tubes when adjusting preload.
Yes, indeed--the annular thrust ball rollers are good. They are used in my Thruxton--no problems what-so-ever. They are used in quite a few of the newer bikes. I do have a 1974 850 project coming up soon and intend on using them. You still have to adjust them just right --not too tight--not too loose.
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