Ask Josh Anything #002

Q&A Episode 2 -

In this Q&A episode of Marginal Gains, Josh answers questions about whether front and rear tires should have symmetric or asymmetric air pressure (and why). We dig into whether no-name Chinese handlebars and wheels are a good deal, or just cheap (and why). Josh analyzes the ongoing thread at Slowtwitch that shows little Crr difference between 23, 25, 28 and 32mm tires. Josh answers why pros are (still!) sticking with tubulars. And there's more. So much more (including — weirdly — that both Hottie and Fatty talk about how Silca and this podcast are beginning to affect their respective marriages).

Interesting Links, Sources, and Additional Reading From this Episode

Chung Method: The original paper

Tom Anhalt's sensitivity testing of Chung

Abraham Olano winning '95 worlds on a flat tubular

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

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  • Nick Dart

    For many years I spent my time focusing on making my bikes lighter. A few years ago, though, I sat down and spent a couple of hours doing some simple modelling in Excel to work out how much faster those weight savings were actually making me, over various arbitrary flat and hilly ride profiles. This was a couple of years before I discovered BestBikeSplit, which does pretty much the same thing. I was shocked how little difference the weight savings made, even for very hilly routes. In contrast, improvements in rolling resistance and CdA were much more significant. Then considering what the best bang-for-your-buck is, low CRR tyres are one or two orders of magnitude better value than lighter components, when you consider the £ per gram (or $/g) exchange rate that you typically have to pay for lighter components. It was a light bulb moment, but despite that, I still today struggle to convince my fellow riding friends (many of which are also engineers and aerodynamicists) not to buy, for example, the cheapest tyres from Wiggle, or to buy a tighter fitting jersey instead of a new carbon frame.

    There’s something about the instant and easily quantifiable difference that a lighter component makes that is somehow more gratifying, unless you make your head rule your heart and do the maths to calculate the (lack of) benefit that those weight savings bring.

  • Tony Geller

    I feel so used.

  • Josh Poertner

    This is a great question and one we’re working into a future episode in a way that is as factual and balanced as possible.. we are targeting a TdF sort of timeframe for this one.. stay tuned!

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