Making Speed: ERO Sports and AeroFit Testing

It’s a scary proposition, introducing triathletes to a velodrome. I mean have you seen those things? I didn’t whip out my protractor or anything, but the banked walls are like… like… 80 degrees (or so it seems). Triathletes are notoriously horrible at bike handling and group ride dynamics, so why would I get on that thing? Well, we’re also particularly anal about bike fit and aerodynamics. So, a group of us found ourselves at the LA Velodrome for an “aerocamp” organized by Coaches Heath Dotson (HD Coaching) and Brian Stover (Accelerate 3). After a morning of learning how to not crash on the banked turns of the track, we got to work. We all left camp faster.

Dusty and me heading up toward the rail to practice some "jumps" --where you dive from the high rail down toward the pole lane. Scaryfun!
Dusty and me heading up toward the rail to practice some “jumps” –where you dive from the high rail down toward the pole lane. Scaryfun!

Heath and Brian are both very capable coaches, but our overnight speed wasn’t thanks to some breakthrough in their coaching techniques. Riding the track didn’t magically increase our speed or threshold power. Nossir, the LA Velodrome is where renowned bike fit expert Jim Manton operates ERO Sports–and more importantly, offers a new service called AeroFit.

I’m going to shy away from the science, so you can read more about the hows and whys of ERO Sports and AeroFit process here. Suffice to say YUP; through a complicated algorithm and a number of neato devices, you can calculate your coefficient of drag (CdA) while actually riding on the track, then take steps to reduce it. Dusty and I are lucky enough to include ERO Sports among our world-class local resources. I can’t say I ever dreamed I’d have the chance to calculate my very own CdA, though. What a fantastic opportunity! It’s like Space Camp for jocks! …or nerds… nerdijocks. Student athletes?

math class

Before I get to what I learned, I should say why I’d sign up for this after being lucky enough to work with some of the best bike fitters across the country. Whelp, the First World Problem with a traditional bike fit is that it’s incredibly difficult to optimize in one day when all you’re doing is pedaling on a trainer. Really, you need to rock in the saddle and feel that kink in your neck when you’re looking down the road (not at a dust bunny in the corner of the fit studio) to know if/how it’s working for you. Plus, you’re only judging the fit at that point by two things: your personal comfort, and the ol’ eyeball test of “yup, looks aero!”

The eyeball test isn’t good enough anymore, especially when it comes to tacking accoutrements onto your bike. Your naked bike frame and aero wheel set don’t account for even 20% of the drag at the end of the day. Know why? Because YOU’RE sitting on your bike too. Your body, your kit, your helmet, the way you hold your hands, and even your hair cause significant aerodynamic drag. Moreover, you may get through a 20k time trial or a sprint triathlon with a naked bike frame, but if you want to do anything longer than that, you need to start thinking about accessories: flat kits and bottles and bento boxes &, &, &! Like a wind tunnel (but much much much cheaper), AeroFit testing on the track allows you to test several scenarios like bottle placement, head position, helmet choice,  and more in order to find your optimal aero setup.

The data isn’t all in, but here’s what I learned:

  • General rules of thumb are good to follow, but not one thing works for everyone: you’re a unique snowflake when it comes to how you fit on your bike.
    • Dusty and Brian rode their nearly-identical Scott Plasma Premium frames and came up with wildly different “optimal” setups in terms of bottle placement and ideal helmets.
    • Dusty and I are both on Scott Plasma Premiums (his is large, mine is small). This yielded different results with optimal bottle setups.
  • With regards to hydration scenarios, rarely does one CREATE speed with the proper choice, as in “this front mounted aero bottle makes me FASTER.” You’re looking for neutrality, as in “can I put a bottle here without slowing down.”
  • Basically, you want to be as small as possible to create less drag. There’s only so much you can do with your body type.
    • A 6’4” 190 lb. dude is going to punch a bigger hole through the air than a 5’2” 110 woman.
    • Boobs are bad. Boobs make for an increased frontal area of slow FABRIC, so, sucks for me.
Aerodynamically, this girl was a mess!
Aerodynamically, this girl was a mess!
  • Hair is also bad. Ladies, tuck your hair up under your helmet like it’s a swim cap.
  • My fit is good (thanks Phil Casanta from Hypercat Racing!). Interestingly, Dusty and I have all the same hip/knee/ankle angles, despite his legs being about a foot longer than mine.
  • The only thing we changed with my position is bringing the extensions out. One “rule of thumb” is that reaching out makes a good position more aero. As I become fit (again) I intend to narrow my pads and lower my front end a fraction.

The net result is that by finding my optimal half-ironman setup, I saved about 15-20 watts from my previous setup. That’s a full season worth of working on bumping my FTP, so I’ll take it!

UPDATES:

Slowtwitch did a spread and a thread on AeroCamp.

2/12 Heath Dotson has written a post on The Making of AeroCamp which features a video of our tri-rific paceline in the velodrome.

Testing an aero helmet option, the new Rudy Project Wingspan 57.
Testing an aero helmet option, the new Rudy Project Wingspan 57.
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