Ask Josh Anything #19

Drivetrains, aero tweaks, and wheels have emerged as the sweet spot for where listeners can achieve marginal gains on their current bike setups, and this episode will really scratch that itch. We do a deep dive into the why, how, and what of Silca's new diamond-polished chains, how properly-lubed chains affect cog and chainring wear and tear, and whether you really need to replace that quick link after each chain connect/disconnect cycle. We also get to the best ways to locate your hydration on long rides and the question of whether — wheelwise — deeper is always better.

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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  • Erik

    Thanks for a great podcast!

    I have a “rule of 105%” question. I live in Sweden where wider tires is popular. I see a lot of people going from allready ballon shaped 25mm on narrow rims

    to 28mm that often grows to even more of a ballon shape. Often 2-3 mm wider on each side than the rim.

    This is among elite race riders. We often race in flat terrain where cross winds is more common than hills. Roads are often okay, but far from smooth.

    Race average speeds is often 42-45km/h. If you have to choose between going “ballon shape” on narrow rim to get better rolling, or going down in tire size to achieve “Rule of 105” what would you guys suggest?

    And also do you measure the rim at the widest point or where the rim ends? (braking surface)?

    Thanks again!

  • Pierre

    Hi Josh, Here is a question for Ask Josh Anything #20 (hopefully) : you probably followed the launch of the Vittoria road tubeless inserts. Seems very promising (though I’ll be curious to see how installation goes with them) but since you are the expert on tire pressure (and now lubes !) and I guess working with the teams you have first hand experience with those inserts, at least in their prototype version… here are a couple of questions : does the change in air volume (since the insert uses some space) requires a change in tire pressure ? To go one step further, would the change in air volume would require to go one size up for tire (let’s say from 25 to 28) in order to get the same ride feel ? Anything else we should know about the use of road tubeless inserts ? Good to see something new in the road tubeless world and probably making the use of the super fast Corsa Speed 2.0 a little “safer” in term of risk-benefit ratio since it seems changing a flat on the road becomes more or less impossible but finishing with a puncture becomes an option (though a costly one since the tire is going to be ruined). Will be super interested in hearing all you have to say on that topic (and what Fatty and Hottie have to say too as this is your great team work/effort that make such interesting and entertaining podcasts !). Best regards, Pierre

  • Nathan

    Hi team,

    Long time follower/listener, first time questioner. Love the podcast so much, as an engineer I really enjoy the scientific, experimental and analytical detail.

    My question is regarding sensitivity of chain/drivetrain wear to drivetrain configuration. I’m wondering what impact there is to drivetrain wear when comparing 2x vs 1x drivetrains? How is drivetrain wear impacted by the removal of front chainring shifting and the addition of a narrow-wide chainring?

    I’ve been running 1x drivetrains on multiple bikes for over 10 years now, and although I haven’t got any quantitative data to back it up, it’s always seemed like my 1x drivetrains have either a longer life and/or that the drivetrain is less sensitive to higher levels of wear. I have on more than one occasion dropped a chain checker on a 1x drivetrain and found it to be well beyond the recommended 0.5/0.75/1.0% stretch without having noticed any perceivable degradation in shifting quality, drivetrain noise or efficiency.




    I’m trying to decide on which gain (maybe marginal maybe not) would be a better place to put my money. Aero frame or aero wheel system? I have a Cervelo R3 with Mercury M5 wheels and 28mm Conti GP 4000 II’s. The tires actually measure 30mm when mounted but the wheels are only 25mm wide. Obviously not adhering to the rule of 105. Would I be more efficient moving to an aero frame like a Cervelo S-Series/S5 or upgrading the wheels with wider rims (Ex Bontrager Aeolus Pro 51 TLR Disc) where I could be at the rule of 105?

  • Jon Okenfuss

    Hey Josh,

    It looks like cross is coming back after a year off. Since I’ve only been waxing my chains for the past year I haven’t worked out what to do about upcoming muddy races. Pit mechanics have traditionally carried a bottle of chain lube to re-up chains after power washing. What would you recommend for situations like that, where drip wax top-ups of Super Secret don’t have a chance at drying? I’m so happy with a waxed drivetrain that I’d hate to have to go back to a wet lube.

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