Ask Josh Anything #009

In this Ask-Josh-Anything episode of Marginal Gains, we ask you to imagine Josh as your boy scout leader, and whether that would be the most awesome — or terrifying — thing in the world. (The jury's out on that question by the way). Then we settle in and talk about how Silca's new online Pressure Calculator works, why aero tires are no longer a thing, hysteresis issues of swerving under hard effort, whether being aero matters when you're in a big peloton, and a lot more. Gather round the fire!

Got a question you’d like to ask? Text or leave a voicemail at the Marginal Gains Hotline: +1-317-343-4506 or just leave a comment in this post!

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13 comments


  • Nick English

    Tried to use the tyre pressure calculator for my children – 8 and 10, riding road bikes at ~35kg rider weight. Pressures that came out for their fairly narrow road tyres seemed super high > 100psi. Is that really correct?


  • Michael Rand

    Hi guys.

    Totally addicted to the podcast.

    Question for Josh. You guys always talk tubeless and clincher latex tube. Totally selfish question here but I am still using Tubular. With the Silca tire pressure page is the tire pressure suggesetions accurate for tubulars?

    Also CRR between tubualr and clincher and tubeless how close it the gap these days?

    I am about to go shopping for a new bike so might go all out and get new wheels and go clincher or tubeless ready if they are actually faster.

    Thanks heaps for the info and the comedy routines while learning.


  • Jeff Dieffenbach

    This comment actually follows AJA10, but I don’t see it posted yet. I get that there’s a lot more to standardizing the tire-rim interface than sizing, but couldn’t tire manufacturers have the primary size marking on the tire be for their recommended internal rim width? For instance, the wheels on my CX bike have a 21mm inner width. I’m running a 33mm tire. If the recommended inner width for that tire was 21mm, they could be marked 700c x 33c/21c or similar. Then, either on the tire itself, the package, or any instructions, they could report the expected width (+/-) on rims in 1-2 mm increments away from that “optimum.” That might look something like this: 700c x 33c/21c [31c/19c – 32c/20c – 34c/22c – 35c/23c]


  • Andy Turner

    Hi Guys great pod cast as always. Have a question for the next ask Josh pod. My brother comments that my ears stick out and it must be costing me 10 watts at least. This got me thinking with every little thing being scrutinised under marginal gains, are peoples faces hair and even ears being looked at in the wind tunnel.

    Should I be sticking my ears back?


  • Dominik

    Hi Josh, i wonder why we do not see (at first sight obvious) benefits developped by evolution in the bike industry, f.e. surfaces similar to shark’s skin or tire tread patterns like soles of cheetahs (made up example). I would expect that nature invested more “computing power” on improving stuff than mankind did so far, why we don’t see more of this?

    Thanks for the great podcast!


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