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More on wheelsets
A lean and lightly-built friend of mine tells me his $300 wheelset is due to arrive anyday. He’s right—there are “good” wheelsets for that price, but I’ve never ridden any that work well for me, even at 3-4X the price (more on that below). He says:
Yeah, that's a problem with the lightweight wheels. Partly because the thin rim is flexy, partly because the skinny spokes are flexy.
Yup. And thin clincher rims also offer the intriguing possibility of having the tire blow off. No fun—I still have the scars (though my personal scrape was from Bontrager carbon fiber clincher rims, both now replaced by Bontrager, perhaps defective).
But for lightweight (< 140 pounds) or less powerful riders, there are more choices. A 190 pound rider like me (180 + clothing, water, etc) is 35% heavier than a 140 pound rider. So a wheelset will be under considerably less force with the lighter rider (which can lead to conflicting opinions about a wheelset). Finally, a few miles/kilometers per hour can also change the load on a wheel significantly (the component of velocity orthogonal to the wheel).
For example, I still have two sets of Bontrager Race X Lite aluminum wheels, which retail for around $1250 a set (one set came on my first road bike, and the other I bought used at a good price). But they handle so poorly that I don’t ride them any more—on a high speed turn, I’ll miss the apex by a foot or two, whereas the Zipp Z3 wheels hit the apex every time, with much less mental attention required. (My wheels are 2-3 years old now, perhaps the current models are improved).
The amount of mental attention required to execute a precise turn at higher speeds (20+ mph) is not to be underestimated, especially when fatigued, or there’s a pothole that appears out of nowhere! Missing an apex (turn in, apex, track out) can mean crossing the center line by a foot or two, a potentially fatal mistake. I’ll stick with a wheelset with no surprises, and skew the odds in my favor.
For two years, I didn’t realize that the reason I felt nervous on fast downhill turns was not due to lack of skill, but rather a too-flexible wheelset that threw me off my line. Accordingly, I always had to brake more than I wanted before entering the turn. This insight into the handling of wheelsets was realized only after I tried the Shimano scandium wheelset (WH-7801-SL), which is very stiff, offering superb handling on corners, but great discomfort on rough pavement.
Precise handling is largely derived from high lateral stiffness, or how much the wheel flexes and deforms under load when turning. Rim, spokes, hub and tire pressure all come into play, but if a wheel flexes, it’s not going to go where the rider intended. Air is cheap, so the tire pressure problem is easily rectified. On the other hand, a stiff tire and/or too high a pressure can cause a bounce or skip effect. This is one reason why high quality tubular tires, with their ultra-flexible casing and round profile, handle so well. The only clincher tire that I’ve ridden that can approach the tubular tires I’m now riding is the 130-140 gram Veloflex Record clincher, with a 350 thread-per-inch casing. As a bonus, tubular tires offer noticeably better comfort over rough pavement, even at somewhat higher pressures.
What makes a good wheel?
“Good” is more complex than something simply well made and reasonably durable. (And price is an orthogonal factor that muddies objective assessment, so consider it separately). Here is how I rank the factors in a “good” wheel:
- top-notch handling; high lateral stiffness with minimal mental effort required to execute precise high-speed turns—“intuitive” handling;
- comfort on rough pavement; comfort at the 100+ mile mark;
- light weight, especially the rim, rewarding acceleration;
- highest quality bearings that require little or no servicing for a long period of time, and with minimal drag (like the superlative ZIPP ceramic bearings in the Z3 wheelset);
- excellent aerodynamics for the chosen goal.
Few wheelsets can meet all of these criteria. The Zipp Z3 wheelset meets all of them (and no, I don’t work for Zipp, or get discounts, etc).
As an example, Shimano makes a scandium wheelset, the WH-7801-SL. I rode them for a few weeks, and found the handling to be first rate. Sprinting response was excellent. But they were extremely uncomfortable on rough pavement. Finally, they caused severe fork chatter under even modest braking on downhill grades (two bikes and two different tires). That’ll wake you up fast when it happens! Were those “good” wheels? Not for me.
