Searching for 30: Pacing a personal record on Boulder’s Flagstaff climb

by CyclingTips


Video by Mat Barlow and Phil Golston

This piece is brought to you in partnership with Rotor. Find out more about our sponsored content policies here.


Flagstaff. Seven and a half kilometres, 605 metres up into the clouds. It’s not the most difficult climb in Boulder, Colorado, but it is the most dynamic. It twists and turns, pitches up and down. The average gradient is 8%, but it kicks as high as 20% and flattens out in the middle. Official times start at Gregory Canyon and stop at a row of mailboxes at the top. An easier first half gives way to the Wall, a 400-meter long stretch you hit after about 20 minutes that makes you want to cry.

The record? Tom Danielson, in 22’47”, followed by Lachlan Morton at 23’08. The top female time? That’d be a scorching 28’13” by retired pro Annie Toth. For mere mortals, though, 30 minutes is the mark to beat for men; 35 for women. Breaking either barrier is a badge you can wear with pride.

Our climber-in-residence, Mike, is made for it. He’s 53kg, 5’5″. Loves the steep stuff. His PR was 30:53, from years ago. He wanted to beat it, so we set out to help.

Figuring out pacing was step one. Mike’s threshold is around 250 watts — about 4.8 watts per kilogram. Quite good for an amateur. We know from experience that it takes about 4.6 or 4.7 w/kg to go under 30, depending on wind and other factors.

Flag opens up with a steep section, 14%, then levels off for about 10 minutes, then kicks up again. The steepest part, the Wall, comes about 5km up, after about 20 minutes of full-gas riding.

The basic rule on a climb like Flagstaff, which kicks up and then drops to almost flat in places, is that you’re better off expending more energy on the steepest parts and then recovering on the flatter sections. This doesn’t mean letting off the gas completely, but giving it 110% more on the Wall and 90% on the flat bit in the middle will yield a better time than going 100% all the way through. Expend more energy on the slower sections, and less energy on the faster sections.

To help with pacing, Rotor sent over their 2INpower power meter, and to help Mike’s overall efficiency, he used their oval QRings. The idea behind the QRings is simple: Match a slightly bigger gear with the most powerful part of the pedal stroke and a lower gear with the weakest parts, at the very top and bottom of the stroke.

The power meter and QRings work in concert — a function in Rotor’s smartphone app called Torque 360 tells you exactly where the strongest part of your pedal stroke is, using data from the power meter. It’s called Optimum Chainring Positioning, or OCP. In Mike’s case, that was the second OCP setting. He rode the rings for a few weeks to get used to them, as is recommended by Rotor.

Mike could see his breath in the cold air as he warmed up. We set out early on purpose. The wind is lighter, and the cold air would help keep Mike cool through the effort. He put in a good warmup. The first pitch kicks up abruptly; there’s no room to work yourself into the climb.

He paced the early slopes well. Just over his threshold for the first section, then just below until half way. From about 16 minutes on, the flat sections disappear. From there, it’s all about staying on top of the gear and giving it everything.

Can he do it?

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