Wednesday, September 29, 2010


As I've gravitated toward longer travel bikes (and the types of trails that make them fun to ride) I've had to reconsider what it means to build durable wheels. Durable for Ricky P. Racer on his 19lb hardtail doesn't mean much when faced with drops and hips and hucks on a 7" travel FS bike. No slight to Ricky--just apples and oranges.

I can build a wheel and send it out into the world and, eventually, hopefully, get feedback from it's owner about how it has held up, and under what conditions it's been tortured. As valuable and necessary as that kind of feedback is, it paints a very small corner of the overall picture. In order to truly understand what kind of torture a wheel is seeing, as well as how often and for how long, I need to be along for the ride, so to speak.

So I build experimental wheels for myself frequently, ride them, note the results, and sometimes even learn something new. That's better, but it's still not enough--it's a sample size of one (in the language of stats types) and that only goes so far.

My answer to this is to build wheels for my friends--sometimes (often!) without them knowing that they needed them. Occasionally the experiment will be on the order of totally underbuilding a wheel just to see what the mode of failure will be, and how long it takes to get there. And sometimes I'll overbuild 'em in an effort to see if anyone notices the extra few grams present to get that increased level of durability. They never notice.

My most recent experiment started back in 2004 when I was building wheels for DT Swiss. I was chatting with the GM in his office and spied an oddball hub on the shelf behind him:

This is a 150 spaced hub, but with a single-speed-sized freehub body. Why, you ask? Massive flange spacing equals massive lateral rigidity. Think of it this way--stand with your feet at shoulder width and then ask someone to push you over from the side. Pretty easy to do, right? Now repeat this, but do it with your feet an extra ~18" apart. See? You're much less likely to get knocked off balance with that wider stance. In case it isn't obvious, your feet in this example represent the hub flanges, and the friend pushing you over represents forces (corners, rocks, roots, ledges, botched landings, etc...) coming at your rim from the side.

Using a hub with massive flange spacing means that you can go waaaaay lighter on the rest of the components. Typically DH or FR type bikes are built with tank-ass heavy rims, straight gauge spokes, and brass nipples, and they'll still *usually* get killed within a season. Nature of the beast is what we've always been told.

Using the hub pictured above, and with the assistance of my friend Skippy as guinea pig, I've found that it doesn't have to be so.

Check it:

What you just watched was a random sampling of the helmet cam clips I have from our 5 days in the Whistler Bike Park. Skippy loves to boost air and is learning to whip the bike out sideways. Sometimes he nails it *and* brings the bike all the way back before impact. But more often he lands while still tweaked out there.

I know of no quicker way to warp a wheel than to land on it sideways as Skippy did several hundred times in the WBP.

But you know what? Despite using an XC rim, butted spokes, and alloy nipples on his wheel, and despite his best efforts to kill it dead somewhere high on the hill, that wheel is still perfectly round, true, and holding even tension all the way around.

I'm not patting myself on the back here because I didn't really discover or design any of this. I merely took an idea that someone else thought of (no one's sure what the hub was designed for, but some have suggested it was part of a gearbox-bike project that never happened) and repurposed it, then did some experimenting.

The end result is a light weight, responsive wheel that'll outlast most any other wheel out there. I dare say it'll outlast most frames and even a fair share of the cockroaches downtown.

-The hubs are rare--I've only heard of one other builder in the US that's using them. I've built maybe 10 of these and I've got another 6 or 8 on the shelf before I need to reorder from Switzerland. But hey--if you're reading this then you already know where to get one...;)
-At best you can get 6 cogs out back. There is a bit of experimentation necessary to get the drivetrain set up this way, but overall it's not too big of a deal.
-You need a bike with 150 rear spacing. Fear not--most long travel bikes are gravitating (<- ha!) to this standard already, regardless of wheel size.
-You'll need to get good at answering questions about it to tech geeks. Or get good at faking a French accent: "Je ne comprende pas, geek".
-Lastly, you'll need to find better reasons for rationalizing a new wheelbuild when this one just keeps going and going and going...

Thanks for reading.


1 comment:

  1. there a reason that both front and rear hubs could not be wider by a..... *factor* of? Seems to me the only weight gained would be from a little bit more material in the hub a slightly wider fork crown...longer axles and an ever so slightly longer spoke. On the rear it would just mean spreading the chainstays a bit....?. But if you can use a smaller gauge spoke and Al nips ..perhaps it would balance out(?) and we could benefit from the the *triangulation* effect??...even on cross country bike...?

    Have you had any experience or success with billet hubs?

    I know a guy with a CNC turning center and about 5 CNC mills that are just sitting most of these days.