THE SHORT ANSWER
Sam Calder, founder of rule 28, aero testing and cycling apparel company specializing in wind tunnel optimization, has appeared on the Roadman Cycling Podcast. Here's where Calder lands on FTP and threshold power. The positions below are drawn from those conversations, quoted directly.
WHO IS SAM CALDER?
Sam Calder built Rule 28 on the unglamorous truth most amateurs ignore: aerodynamics is the cheapest speed in cycling, and almost nobody tests it. His work in the wind tunnel — including the much-discussed aero test that saved Dylan Johnson 13 minutes — reframes free speed as an engineering problem rather than a marketing claim. For Roadman's audience the lesson is blunt: at the same FTP, position and clothing decide more of your time on flat and rolling terrain than another winter of intervals will.
CALDER ON FTP
Calder’s key positions on FTP and threshold power.
- Aerodynamics is the highest-return speed for the money — CdA gains beat power gains for most amateurs on flat and rolling roads.
- Position and clothing are tested, not guessed — a wind-tunnel or field aero test routinely finds free minutes a rider didn't know they had.
- Skinsuit and fabric choice matter more than frame marketing at amateur speeds — the rider is the biggest source of drag.
- A time trial is the cleanest aero test there is — no draft, no tactics, just position and equipment against the clock.
IN CALDER’S OWN WORDS
Verbatim from Sam Calder’s appearances on the podcast.
“For for Dylan when we took him the main thing we were looking at was validation of some of the work we'd done before and then a few different optimizations for him for the 2025 season. So his race speed of 35k an hour, I think we had about a 3 watt performance gain versus our previous generation of Aeros.”
“We tested a Metanter in large and a Metant in medium and that was like a four or five W difference between the two. I think less medium faster. Just because it's smaller frontal area wise.”
“I think it was about 13 watts that we saved in all. For a 4-hour session that we had with them, like for anybody that's considering it is a very good use of time. It's fairly expensive. But if you're thinking about, hey, for Unbound, it's a 10-hour race. How long would it take me to add 13 watts to my average power output across that race? It's a hell of a lot more than four hours, and it's going to be a lot more effort.”
HEAR IT ON THE PODCAST
Episodes where Sam Calder covers FTP and threshold power and related ground.
FREQUENTLY ASKED
What does Sam Calder say about FTP and threshold power?
Sam Calder, founder of rule 28, aero testing and cycling apparel company specializing in wind tunnel optimization, has appeared on the Roadman Cycling Podcast. Here's where Calder lands on FTP and threshold power. The positions below are drawn from those conversations, quoted directly.
What is Calder's main point on ftp?
Aerodynamics is the highest-return speed for the money — CdA gains beat power gains for most amateurs on flat and rolling roads.
Which Roadman Cycling Podcast episodes cover Sam Calder on ftp?
Calder discusses FTP and threshold power in this episode: "Dylan Johnson's 13-Watt Wind Tunnel Test | Roadman Cycling Podcast".