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tech-talk: how many spokes?

I recently heard my umpteenth story about someone who put low-spoke wheels on a bike and had a, shall we say, mishap. (In this case, he endoed when his front wheel failed, and wound up in significant facial distress at the ER. I have been reassured that his injuries were, in medical parlance, "not life-threatening" and with a steady supply of vicodin he'll recover.)

So I decided to look at the latest fad of low-spoke wheels.

Basically, the reason that low-spoke wheels are popular these days is that, with the right combination of materials and proper spoke tension, it's possible to get a stiff, highly responsive wheel that corners beautifully, rides smoothly and is lighter and faster all around. If you're racing this makes a LOT of sense. Lighter and faster IS good, to a point. Of course, other variables must come into play, including the kind of riding you're doing, what kind of bike you have, how much you weigh (most professional road bike racers weigh between 135 and 160 lbs, and 180 is considered a rather big rider) and how hard you ride the bike (i.e., do you hammer on beautifully clean, fresh, smooth asphalt all the time; or do you curb-hop (admit it, we all do from time to time) on real city streets?).

Here's an example of a low-spoke wheel set:





And here's another (interestingly, this set is advertised as being intended for use on a tandem, or two-seater, bicycle, and so must bear twice the weight):





Both sets of wheels look light and fast, right? Well, they probably are. I wouldn't know for sure, since none of my bikes has anything resembling them. But here's the thing with low-spoke wheels, especially when used in daily, hard-riding, NON-racing applications: when one spoke breaks, the wheel goes TOTALLY wonky. Tacoed. Potato-chipped. So warped it could fit in a can of Pringles, but will no longer turn when mounted in the bike frame or fork.

On a wheel with only twenty spokes (as each of these front wheels has), when you break one that leaves only 19 to take up the tension and stress of the relationship between the rim and the hub. And since most racing bikes have precious little clearance anyway (for bigger tires, or fenders, neither of which a racing bike needs or wants), that means that nine times out of ten a broken spoke will mean you can't ride home.

On a racing bike, in a racing situation, that is probably okay. Racers have mechanical support along the course -- cars filled with spares that will come along and help the rider get back on the bike. And in fact, these low-spoke wheels were designed with racers in mind, racers who can count on that kind of support so they will never be stranded. (As someone who used to do neutral wheel support at road races and charity rides, I know well the look of relief that crosses a rider's face when s/he sees our support van. That look means s/he won't have to walk, and believe me, that rider is grateful.)

The trouble starts when a real-world bicyclist (i.e., a commuter or recreational weekend rider) tries to run those same wheels on a bike that's being ridden very hard, or by someone with clunky bike-handling skills, or in an area with horrid road conditions, or all of the above. If you break a spoke on one of these low-spoke wheels in that situation you will very likely have to shoulder the bike and walk, or whip out your cell-phone and call home for a lift. And that's in a best-case scenario.

Imagine what might happen to this front wheel --





Or this front wheel --





--if one spoke broke during a ride. Count the spokes. Each of these last two wheels has 36 spokes, so if one breaks there's still 35 spokes left to handle the stress. Assuming that the spoke broke from age/fatigue/impact or all of the above, the rest of the spokes will keep the wheel from going SO wonky that it can't turn at all. On a bike with sensible clearance for bigger tires and fenders, that 35-spoked wheel will probably still turn, albeit drunkenly; and if you open up the quick-release on the brake caliper you can probably ride [carefully] all the way home.

Remember the "tandem" wheels in the second photo above? That rear wheel has 24 spokes. Here's what we used to call a tandem wheel. Count the spokes:




(in case the photo turns out poorly, that wheel has forty spokes. Yes, forty.)

Again, there are other factors involved, including frame design and weight/riding style of rider; but the trend towards lower-spoke wheels worries me on many fronts. When I see a racy-looking bike like the Trek "Portland" (designed to be a "modern road commuter") and it has lower-spoke wheels, then consumers are getting a mixed message about what makes for a sensible (notice I didn't say "good") commuting bike.


The Trek "Portland":





Here's a classic example of a bicycle designed by racers for commuters. I'm sure the bike is "good" --  it rides smoothly and shifts crisply and feels great under the rider -- but I won't call it "sensible" for commuting in real-world conditions. Fender clearance is so limited they had to design fenders that fit behind, but not through, the frame. Wheels have 24 spokes each, with tires that are likely no more than 25 to 28 mm wide (for the non-geeky who read this blog, that's a pretty skinny tire, barely an inch wide, for daily commuting). The handlebars are positioned a few inches below the saddle, meaning the rider is leaning over quite a bit. If you're a racer and this is your "training" bike, it makes sense. If you're not a racer and you just want a reliable bike that will get you to and from work, well, In My Humble Opinion, there are more sensible -- and more affordable -- bikes out there.

I guess what I'm really saying is that low-spoke wheels are symptomatic of a larger, overarching issue, and that is that too much of racing's "here today, gone-at-mile-40-where's-the-damned-neutral-support?" technology is trickling down to bikes that don't need it, for riders that don't need it; and the only way to sell it is to market like mad the idea that these non-racing riders DO need it. This is how the Trek Portland was marketed; this is how low-spoke wheels are being marketed; and this is how the new 11-speed drive-trains will be marketed next spring to an unsuspecting bike-riding public that not only doesn't need this technology to get to and from work, but won't truly benefit very much from it, either.


That's why my bikes all have wheels that look basically like this:





--so they won't be as likely to end up looking like this:




(and yes, that entire low-spoke wheel failed.)

Comments

Yargh! This is one reason I vastly prefer my standard-spoked touring bike for commuting. It runs 700x32c tires on standard wheels that give me more cushioning, more width, and more strength to handle the daily grind. Regrettably it doesn't have much wheel clearance, which has always annoyed me as a design decision. It's a touring bike, I don't need racing-style brakes. I see a lot of people commute on racing bikes. I tried it a few times, but it's just not comfortable for me -- the bike seems ill-suited to that environment.

I've always thought the Portland was a bit stupid -- the components are all selected as if it were a mid-grade racing bike, but it's advertised as "urban". And it's expensive! The 520 is a comparatively sensible choice.

Nightmare Failure

That last image you have came from the rider hitting a nasty pothole during a race. (And other riders ruined wheels, but no others failed in this manner). A few of us have been chatting about that via private emails.

The really, really scary thing to me is that it seems to me that the rim failed first - it looks to be one of the Dura Ace (premium race level) Carbon wheels. The hub is zip-tied to the top, and via the original (warning - graphic post ER photos in the stream), seems only to have minor (albiet catastrophic) failure. The spoke heads (straight pull) look untouched. Our guess is that when that rim broke through upon impact (all-too-frequent carbon failure mode), all that forward momentum got directed into the hub shell and it never had a chance. Nasty, nasty business. 32 count never looked so good.

The other funny thing is that until the use of carbon in the rim, the weight savings in such wheels wasn't all that great, as the designer would have to beef up the rim to deal with the massive increase in tension at wider spaced points on the circle. And those big gaps make it easy for sticks and squirrels to get lodged therein.

Spoke-pain

Last spring I bought a hybrid- a Fuji absoulte. I broke five spokes in the first six weeks of commuting. The bike shop got tired of replacing the spokes so they replaced the wheel with a double walled AlexRim. I broke 7 spokes in a month of commuting on the second rim. They switched to yet a heavier rim.

Sports people underestimate how hard commuting can be on a bike. I don't consider myself a hard rider. I don't race or do tricks. But I do ride a lot of miles (500/month), on paved roads unswept by the city, in all sort of weather conditions. I don't hop curbs because I'm spoke sensitized. But I hit potholes, ride over railroad tracks, run over glass, etc. I use panniers to carry lunch, work clothes, and an occasional book. So the extra weight of a rim seems to be a ridiculous issue.

Consistent commuting can be hard on a bike. I am planning on making the Fuji my back up and getting a tough touring bike with raised handlebars.
Yeah, but low-spoke wheels are "kewl."

Common sense seems to lose out a lot. This trend reminds me of the early days of personal computers when everyone had to have all the latest bells and whistles available. Now, at least, a computer salesman is likely to ask you what you plan to use it for.

(Anonymous)

Great post

Great post, and it's refreshing to hear from someone who knows what they're doing. Although I haven't broken a spoke with my low spoke count wheels, I cracked a rim (http://www.apertome.com/blog/2007/10/08/dr-ts-funky-50-cracked-rim/). My LBS guy looked at me like I was crazy for saying I thought the wheels didn't have enough spokes.

Now I have higher spoke count wheels (came with my Surly Long Haul Trucker) and I'm much happier.

Apertome (http://apertome.com/blog/)
It's fairly obvious that Trek hasn't paid much attention to Madison cyclists in years. If you see a Trek (or Gary Fisher) on a local bike rack, odds are it's older. Usually a *lot* older, with a steel frame. You also will see a lot of the 7x00 hybrids, and the odd bike from their last bout of selling Euro style commuters. All of 'em (even the fixies) have nice sturdy wheels.

Newer, racier Trek stuff just doesn't get ridden for street use the same way their older stuff does. You'll see plenty of new Bianchis tho.

Sometimes I wish Trek would wake up and actually look around town. Instead, I'm still trying to stave off the annual urge to bash Trek after all their attempts to run over pedestrians at Trekworld.