AJA 30: Debunking the Valve Stem Location Myth


We take our mission of making a big deal about the little things very seriously in this episode, where we talk about whether there's any actual basis for the superstition behind where you rotate the wheel to before inflating a tire. We then move to the admittedly more pragmatic questions of how much of a draft an aero rider provides to the riders behind them, the low-hanging gains for DH racing, and the problems with racing a 1X setup on the road. And that's not even remotely close to all (even though we could have talked about each of these questions for a full hour).


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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  • Tjaard

    Schwalbe just released a new DH tire, and they claim not only lower rolling resistance, but also improved aerodynamics.
    So there certainly are people working on that in DH.
    BTW in Leogang riders were hitting the speed trap at 50 km/hr, and of course, no drafting.

  • Nick

    Another hot wax question – should you use a magnet to ‘clean’ debris out of the hot wax, or is there anything magnetic that we want to keep in there?

  • Nigel Wade

    Hi Guys

    Long time listener here and I especially love it when it gets super nerdy and into the weeds.

    As a gravity mountain biker, I would definitely like to hear more on the downhill topic. Personally, suspension is my main area of interest (which is a rabbit hole in itself), but there are so many interesting aspects to explore into going fast down a hill.


    Nigel (the ShockWiz guy)

  • Andrew

    Hi Josh and crew, great episode as aways.

    I have a question about the marginal gains of shoes and pedals that doesn’t seem to get talked about much.
    • Firstly, are stiffer soled shoes measurably faster? Do you have a feel for the watts sacrificed in choosing nylon vs carbon soled shoes and whether this would change with speed/power?
    • Secondly, are road pedal systems more efficient and therefore faster than 2 bolt mtb systems? My perception based on feel is that as long as the pedal/sole interface is stable there is no difference in comfort but am unsure whether this implies similar efficiency of power transfer?

    Happy to ignore weight and aero considerations of the cleat systems in the above discussion. Secretly hoping your response justifies my ongoing use of mtb shoes for road racing ;)

    Thanks in advance! Listener and fan since first hearing Josh on a Tour de France pit walk down podcast from the 2018 Stage 3 TTT.

    Andrew from Wollongong

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