Boxerworks.com

This discussion makes me wonder if there are sealed bearings available that would retrofit to our bikes.

Zombie Master wrote:

Major Softie wrote:Agree with Chuey. Lubrication will not extend head bearing life (unless the alternative is ignoring them until they've dried out). Those bearings are designed for a turning load, and, instead, they get nothing but sudden impact thrust loads, and almost all in exactly the same orientation. The solution is not a zerk fitting, the solution is a complete re-engineering of the steering head: a different way to carry those loads. I don't know what exactly that solution would be, as, if it were simple, someone would have done it a long time ago.

The telelever does address some of these problems, by reducing the severity of impact load. Still it's difficult for me to believe, that well adjusted lubed tapers would not last a lot longer than ignored ones. Every time you tun the bars the ultra special synthetic miracle grease would get redistributed to the impact load area. They should make the races and bearing easily rotate-able.

They should do something for the owners.

What I really was trying to say, and I thought I said this pretty clearly, is that the adjustment is the critical factor and makes much more difference than lubrication on those bearings. They are not spinning unless you have a much different riding style than most people do. They are constantly withstanding static loads and lubrication does not come into play the same way as it does on bearings that spin.

Chuey

What if we just do away with the rollers and machine a solid cone to turn against the outer race.

George Ryals wrote:What if we just do away with the rollers and machine a solid cone to turn against the outer race.

Interesting thought, George.
Would this scenario increase or decrease the need / frequency of lubrication or replacement ?
Although a plain bearing would distribute load over a greater area, and potentially reduce wear,
I envision that this might also translate as increased frictional losses affecting rider input.
And also a problem with lubrication, esp. of the lower bearing.

A "Self lubricating" bearing material or grooves cut into the bearing surface may solve the latter ...

"Self lubricating" and "life-time sealed" bearings always raise a red flag for me.
It will be THE BEARING'S life-time, not mine, that determines the time of failure –
and this will most often be a shorter length of service than with a properly maintained bearing.

I am wondering how long these bearings tend to last for most? On my slash five, I have 40k miles on the steering head bearings and original grease. They are still silky smooth without signs of notching. On my other bike, they have 92k miles. I greased them about 5k miles ago. They are working well also.

I think that one of the keys to steering head bearing long life is having them adjusted properly. If there is any play in them, the notching will appear faster.

vanzen@rockerboxer.com wrote:

George Ryals wrote:What if we just do away with the rollers and machine a solid cone to turn against the outer race.

Interesting thought, George.
Would this scenario increase or decrease the need / frequency of lubrication or replacement ?
Although a plain bearing would distribute load over a greater area, and potentially reduce wear,
I envision that this might also translate as increased frictional losses affecting rider input.
And also a problem with lubrication, esp. of the lower bearing.

I have a wood turning lathe that has large tapered plain bearings in the head, because they last forever and can handle very large loads. They would not increase frictional losses, as the lathe head can turn a couple thousand rpm. The problem with such a bearing is that it is not designed to run with grease and would squeeze the grease out pretty quickly. It is designed to run with a constant oil supply from an oil cup filled with 30wt non-detergent oil. So, in use, it is always seeping oil. Pretty messy for a motorcycle steering head. An "upgrade" for that lathe is to replace the bearings with rollers. They aren't as strong, and simply don't do the job as well in most ways, but they allow higher rpm and stop the seeping. I prefer the tapered plain bearing.

A tapered roller cartridge would probably be the best in terms of load bearing capacity and ease of replacement. Proper preload is the issue for them too.
Whether it's possible to retrofit would be a job for someone who has a lot of time and machining eperience.
BMW DOES make serious errors in bearing application, witness the needle bearings in the swing-arms of the new GS bikes. a heavy load that only travels to-and-fro...NOT a needle bearing application at all. And you can buy aftermarket plain bearings to install when the stupid needles wear out...

Here is the web address for the Oilite bronze bearing replacements. http://www.rubberchickenracinggarage.com/bushings.html

In all honesty, and IMO, for as often as the steering head bearing maintenance process is necessary,
and given the nature and life-span of tapered rollers,
this combined with the fact that I actually enjoy taking sh!t apart just to see if all is right,
( add grease if necessary ) –
I would first question the need for an improved regiman ...

There will be no getting around the essential fact that
regular hands-on involvement is not to be eschewed
and will, after all, always keep you advised of "condition"
and one or two steps ahead of "sudden catastrophic failure".
"Maintenance free" will only be a lie to placate those with a fat wallet
and those too lazy to attend to proper maintenance.

I'm not a trained engineer so please consider that when reading my comments here. I don't know all the proper terms.

The shallower the angle of the roller bearings, the better they will handle the upward load on the lower bearing. The other load that those bearings see is the back and forth load. A very precise set of rollers set between precisely ground steerer tube and inside of head tube, hardened of course, would be plenty strong for handling the back and forth load. At the top bearings, the loads are much less as far as I can tell and some fairly large ball bearings would handle those loads well enough.

In my experience, the stock bearings do a pretty nice job for us. Don't other brands have upgrades to bearings like ours?

Chuey