Ask Josh Anything #011

Ask Josh Anything #011

Josh, Hottie, and Fatty are back with all the bike-related questions too nerdy to be asked (or answered) anywhere else. In this episode, we tackle:

  • What lessons from track racing can be applied to singlespeed mountain bike racing?
  • All else being equal, are fewer spokes more aero?
  • Is a matte finish on helmets faster than a gloss finish?
  • What are the fastest patterns for tire treads?
  • What marginal gains are there to be had when racing your indoor trainer online?

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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14 comments


  • Brian Feinberg

    Hey, I’ve been listening to these for a while, just thought of a question. I’m a randonneur, and typically rando bikes have a large handlebar bag in front for gear. That’s never been my style, but I saw that Jan Heine is claiming that actually these big bags in front are somehow more aero. Now, he’s clearly knowledgeable, but – how can that be? A big rectangle in front is the opposite of aero, right?


  • Andrew

    Question on best location for a mini pump bracket. Downtube or seattube bosses? I just unboxed a Tattico and the bracket is going on my commuter bike.


  • David

    Hi guys,

    Love the show. I hope you are all keep healthy and safe.

    My question is a small one. Would you think that chainring bolt covers would have a negative performance impact?

    I mean, something like this, without covers:

    https://scontent.fsyd3-1.fna.fbcdn.net/v/t1.0-9/p720x720/35229374_1949187128484838_480917645730775040_o.jpg?nc_cat=105&nc_sid=110474&nc_ohc=7AWdW1eCylwAX9Fnzrs&_ncht=scontent.fsyd3-1.fna&nctp=6&oh=88425f3677f2b32d27b3c58962e57486&oe=5E9F30D3

    Compared to adding covers for aesthetic reasons, like this:

    https://pbs.twimg.com/media/DP9_OuLXUAEVGrI?format=jpg&name=4096×4096

    And this:

    https://absoluteblack.cc/images/katalog/72/absoluteblack_ultegra_6800_duraace_9000_bolt_covers3.webp

    My mind tells me.

    1) There will a weight penalty. Although ever so slight.

    2) There would be an aero penalty as there is simply more “stuff” spinning through the air during each revolution (the A in CdA).

    It is David asking. Last question I asked (about black being cooler at over 23kph) you started calling me Greg or something :-)

    Keep up the great work!!

    Thanks.


  • Ron

    Hi guys, just a follow up to my last question: one item that I do not recall Josh talking about is something I will call tire squirm for lack of a better term. It came to mind while riding my fat bike which is the extreme case. That is if the tire pressure is lower and runs well on a poor traction surface once you hit pavement or another good traction surface the tire starts to self steer (squirm). Now to the real question, in something like a criterium where there is a lot of cornering and accelerating, is there a different tire pressure scenario taht may mean having a bit more pressure since the tire is the last part of the power transition system to the road, one might think that stiffer is better in this case and the just rolling along (ie constant speed) CRR is maybe less important?


  • Nate Lee

    Marginal Gains type of question with regards to indoor riding on a trainer. I used to ride on a “wheel-on” fluid trainer with my old aluminum frame & wheel bike. This trainer required a riser block to level the bike. I recently purchased a Wahoo Kickr, and have been very pleased with the handful of rides I’ve gotten so far on my new Carbon bike (Scott Addict). The sound level and not requiring a block to level out the bike has been a welcome improvement. That being said, I doubt the engineers designed: frames, forks, wheels, hubs, etc…to be ridden on a trainer.

    Question(s): Would a riser block under my front wheel (Zipp 303 with 28c GP5000 tire and butyl tube) help/minimize additional stress from going into the wheel (wheel, spokes, hub), fork, head tube, or headset? Should I be checking my front tire pressure periodically when I ride inside on the trainer to keep it at a higher or lower pressure than I would run on the road? Are there any other things along those lines that potentially would minimize any effects of riding inside?

    I know, I know, it depends…

    Thank you; I enjoy the podcast.


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