Thursday, October 27, 2011

Musings On Hubs

King hub: Image courtesy of
I got an email from a mechanic friend of mine the other day asking me to discuss hubs. You know....those things in the middle of your bicycle wheels that the spokes attach to? Yeah.....those are hubs.

And, believe it or not, hubs are not at all created equal. This starts to bring in opinions on what works best, and what doesn't. However; there is one small detail that all hubs need to perform well, and if neglected, you really don't have a leg to stand on comparing your hub to another hub, especially if you are having issues. What would that be?

Service. Maintenance. You know.......overhauling your hubs.  It has to be said- your hubs and your entire bicycle, for that matter, need to be checked and maintained on a regular basis. Really. I don't know where folks get the idea that you don't have to do anything to a bike to keep it rolling. You do have to work at it. These things need attention, and if you don't give them attention, they will bolt on you like an un-loved woman.

So, with that out of the way, and assuming you are taking great care of your particular hubs, what is it that works best?

Shimano internally geared 3 speed hub diagram
Well, best for what? In the case of my friend, his question was in reference to gravel grinding. Gravel is an insidious enemy of bicycle parts. Just harmless dust, eh? Well, that stuff gets into hubs, and then acts like a grinding agent. It will pit and destroy hub bearings fast. How you keep it out is with seals.

Not the marine animal. No, we're talking about little rubber, plastic, and metal barricades against intrusion by dust, dirt, and water. Sounds great then. Get some seals and you're all good, right? Not so fast there.....

There are bearings, and there are bearings. Some are sealed with plastic barriers in a stainless steel case, much like what you see in the Chris King hub, and some are ball bearings that rely on a "labyrinth seal" system, which is what Shimano mtb hubs have used, amongst others. Which is better is a matter of opinion, but generally speaking, the type in the Chris King hub, or "sealed bearings", as they are known as, get the lions share of nods amongst aficionados of mechanicing.  

The thing is, if a bunch of grit does make its way into the "sealed bearing", it is going to stay there until it chews everything up eventually. The labyrinth seal lets things in and out, so maybe you will get long life, maybe not. Again, servicing a labyrinth sealed system is pretty easy, but you actually have to do it. The sealed bearing system could be serviced too, but it isn't as easily done.

A serviceable hub?

My grandfather was a farmer a long time ago. When I was a young lad, I would follow him everywhere he went, watching his every move. He was my hero at the time. Well, as he would go to hitch up an implement to the ole John Deere A Model, he would grab a grease gun from the engine bay, and grease the implement before he used it by squirting a few pumps of grease into a zert  on different points on the implement. This forced old, watered down, dirty grease out, and replaced it with new, fresh grease. Maintenance.

You know what? There were bicycle hubs that you could do the same thing with. Brilliant idea, and too bad it doesn't exist as new anymore. It was developed by Charlie Cunningham of WTB, and it was called "Grease Guard". Suntour licensed the technology for a while as well. I had a full XC Pro Suntour Grease Guard gruppo on my first serious mtb, and like my grandfather, I greased those bearings regularly. Never had any problems keeping those bearings smooth and trouble free. In fact, the wheels still live on my Xtracycled Schwinn, and the hubs have never been apart. Don't need to be. As long as I can grease them.

Seems to me it is an idea worth reviving, especially for us dirt and gravel riders.


JR. Z. said...

I, too, grew up the son (and grandson) of a farmer and buy parts (especially pedals and BB for my fatbike) that can be drilled and tapped for Zerks (found at most hardware stores). If you're carefull with a drill and tap, it's pretty easy to convert most parts on a bike to utilize this system. Great post, didn't know the WTB hubs existed.

Craig said...

What about bottom brackets too? Right now I need to purchase a Shimano/ISIS tool in order to service the damn thing. Before that I had to buy a new front hub because Shimano forgot to add the correct number of balls on one side the the bearing and eventually it bit me. My rear hub needs servicing again now.
My head tube needs greasing too, not something I look forward to.
All these nice fandangle ceramic and stainless bearings start out nice, but in this throwaway society, maintenance is an afterthought for most designers and manufacturers, instead they opt for compactness and lightness in order to achieve the latest and greatest impulsive consumer driven items.
It's not just bearings either. There's my old Manitou fork that has the grease holes stuck fast and won't let lubricant through, and I've had to use electronics cleaning solvent spray on my change levers because of the gunk in the ratchet mechanism and lines.

Guitar Ted said...

@Craig: I think you've got a case of severe use and not-so-serviceable parts going on there. Of course, things could be made easier to service, and more longevity built in. But as you say, planned obsolescence, or consumer ignorance, or both= has led to a situation where we have modular systems that are "go-no go" and are not serviceable. sad.

Unknown said...

Why do you think this kind of hub was discontinued and other makers didn't adopt the WTB platform?

Guitar Ted said...

@Kellie: I can not say with authority, but I would suspect it may have something to do with patents and licensing.

MG said...

Patents, licensing and the fact that parts simply didn't wear out, so you never had to buy new ones!

There are very few companies in today's world that subscribe to that business model. But those are the companies I admire. Sadly, WTB isn't one of them anymore...

craigcvr said...

Sealed bearings, so water can't escape.