Ask Josh Anything #005

Hi,

What is better for short distance triathletes (sprint distance – 20k bike) – an agressive position on the bike with a smaller frontal area and not really sustainable for longer rides comfortably, or a more relaxed position which will be a bit more comfortable for longer rides but has a larger frontal area?

Thanks!

At the start line of TdF Stage 2, the TTT, I noticed that Thibault Pinot’s face wasn’t clean-shaven. Aero penalty?

As a mechanical engineer and avid cyclist I’m loving the podcast. I stream it to my brain whilst doing my day job. My question that I have been thinking about for ages is related to aero dynamic effect in strong winds. For me I’m 178cm, 83kg rider on a Cervelo S5 2019 (lovely bike). Now if I’m riding into a 30kph head wind of course I’ll get down low into the drops to reduce the drag and go a little bit faster. However I turn around to head back and now have a 30kph tailwind. Is it faster for me to still get into the drops or sit up and present more cross-sectional area (my back) to the tailwind for assistance? At what wind speed should I change this positioning?

Thanks Mike

Thanks for answering my question! I wish to point out that my BMC isnt solely used for commuting and yes I have a secure cage to lock it in with a Kyptonite lock.

On shoe stiffness…

Stiffness near where the pedal is contacted can definitely be helpful, to distribute pressure across the foot. Platform pedals have always avoided this by having the platform itself be really wide, but in the case of clipless, the cleat and/or pedal where force is transferred can sometimes be very narrow.

However, it’s hard for me to visualize how stiff arch support from the heel through the ball is useful. “Hysteresis” doesn’t seem like an adequate explanation, because it’s not obvious to me that a significant amount of power transfer ever goes through the back half of the shoe. Pedaling form is a lot like running form, the drive force tends to be pushed out from the front of the foot. The back half of the shoe mostly seems to be along for the ride.

Things would be different if the shoe was rigidly locked to the tibia rather than to the foot, or if pedals were forced to stay at a constant tilt through their revolution. In these cases, simply pushing your lower leg downward would transfer useful drive force into the shoe even if the foot was left to flop around, and the shoe’s sole would transfer that force out to the pedal. But this would be quite different from the pedaling form that humans actually use while riding bicycles, at least those of us who have two complete legs and healthy feet.