Musings On Hubs

King hub: Image courtesy of Cyclingnews.com

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.