This chapter in our Kona Survey 2004 is a little bit of a departure from raw numbers per se. When you've got a lot of data on a lot of bikes the temptation is to mess around with the numbers, and—God bless us—that's what we've done.
You hear the comment (or something like it) all the time: "I like the price of those Cannondales but I don't want to get beat up by the frame." But those who've been in the bike milieu for a long time will answer, "Ever tried to measure the deflection of a frame in the vertical plane?"
"Ah, but it's not as simple as that," comes the reply. "It's vibration we're talking about, the different frequencies at which various frame materials vibrate. Conductivity and all that."
I've got all these Kona numbers. Why not put my spreadsheet to the test? How does a frame material affect one's performance? Perhaps apply the various materials to a single measure of effectiveness: How easy is it to run 26 miles after having the snot vibrated out of you for 112?
For this exercise I considered the three largest undiluted sample sets of bikes made from the three chief materials: Cervelo for aluminum, Litespeed for titanium and Kestrel for carbon. Each of these manufacturers yielded sample sizes of well over 100 participants, surely enough to generate a statistically relevant set.
Cervelo's riders generated the fastest overall bike/run times, but it could be argued that these were also the most earnest, motivated, and athletic subjects. Why? Two factors. First, Cervelo's customers were probably those who made the most recent purchases, as this company has gone from 57 bikes in Kona to 132 bikes in two years. Second, Cervelo's steep seat-angled bikes made up the huge majority of its Kona users, while a large portion of both Kestrel's and (especially) Litespeed's customers were made up of those who chose these brands' road geometry bikes. Perhaps this meant these riders were therefore less likely (on average) to be younger, trimmer, fitter athletes, and more likely to be slightly older, better-heeled, more comfort driven (who knows?).
More apropos than raw elapsed time might be the ratio of run time to bike time. In the case of Kestrel and Cervelo, the ratio is basically the same. Both customer sets tended to run a time that was 70.5 percent of their bike time (the difference in bike-to-run ratio between these two brands measures out in seconds, not minutes).
The Litespeed brand's customers measure out a slight bit faster on the bike versus the run (72.3%). This equates to about a 5-minute slower marathon, or an 8-minute faster bike split, depending on your view. Both sides can be argued. One might claim that, "based on cycling as a barometer of ability, Litespeed owners will run 5 minutes slower than they ought, compared to those who ride Kestrels or Cervelos." If Litespeed were my company, I'd argue that "Using one's run time as a barometer of ability, you'll ride 8 minutes faster on a Litespeed than if you rode a Cervelo or a Kestrel."
| Activity |
Carbon |
Aluminum |
Titanium |
| Kestrel |
Cervelo |
Litespeed |
| Run |
4:05:15 |
3:56:45 |
4:08:04 |
| Bike |
5:48:20 |
5:36:05 |
5:43:25 |
| Total |
9:53:35 |
9:32:50 |
9:51:29 |
| Ratio |
70.4 |
70.5 |
72.3 |
Maybe more of Litespeed's owners chose shallower angles than, say, Cervelo's owners, and so ran a few minutes slower on average (see What science says of seat angles). I haven't yet run the numbers on the seat angles versus bike-to-run ratios, I'll report back when I do.
In any case, this one set of numbers might go some small way in diminishing the myth of demon aluminum, the bone-jarring comfort killer. My view? A neoprene seat pad, or lack thereof, makes triple the difference of one frame material or another.
This isn't to say that frame materials won't make a difference. I guarantee that of all these roughly 400 Kona riders, more Cervelo customers returned home from Kona with frames that had little top tube dents thanks to the trip home in the bike case. More Cervelo and Kestrel customers returned home with frames that had chipped paint. These athletes' Litespeeds will, on average, last longer in salty atmospheres (both salt air and salt from sweat) than anything made from steel or aluminum. Titanium is your material if you want a bike that will last a long time and stand the test of roof rack and airline travel.
On the other hand, Kestrels are damnably hard to break and when they do, they don't break catastrophically. Cervelos have tube shapes that neither company can match, and they can alter tube shapes and geometries more easily, year to year, than can Kestrel or Litespeed. Kestrel has wall thickness variations that the other companies can't equal.
Frame materials do allow for a variety of comfort features, assuming the double-diamond bike frame design is eschewed. Perhaps Kestrel's seat-tubeless designs allow for vertical compliance. Titanium allows for a small shock to be inserted in the seat stay, with the chain stay acting as a spring (you can't do that with aluminum's modulus). But if your frame contains all 8 unsuspended tubes of a double-diamond frame, you'll get more vertical compliance in your saddle's rails and shell than in your frame's tubes.
The moral is, differing frame materials mean big differences in what you can do with a bike frame. But comfort is not the most important point around which these materials pivot. This mini-study might go some small distance in helping demonstrate that.
