Marginal Gains Monday – Overview

So I jumped the gun a bit last time charging straight into discussing a specific topic. Obviously I had aerodynamics on the brain thanks to the recent wind tunnel session. This time I’ll step back a bit and outline what I intend to discuss over the next few weeks.

There are a lot of claims made about the efficacy of various bits of equipment – to the point that athletes stop believing in the science of speed as the marketing claims rarely eventuate in the real world. My aim is to give a realistic view of the significance of various elements.

I like to look at purchasing speed in terms of return on investment (ROI – you can see my business analyst alter ego showing here) or in this field – speed per dollar. There is a lot of ‘common wisdom’ that is not very wise and is only common by virtue of frequent repetition. One bit of advice I’ve frequently heard is ‘don’t worry about getting a tri bike – just put some aerobars and race wheels on your road bike’ – as we’ll come to see (over the course of the series) this is terrible advice. Along the way I shall debunk some myths and lay out a sensible upgrade path for those looking to optimise their performance.

Obviously the first topic I wanted to cover was body positioning as it is by far the most significant impact on performance.


This chart gives a rough breakdown of where my power goes if I’m going 40kph on a flat, somewhat rough road in fair (but not great) weather conditions.

You’ll note that aero considerations are by far the largest slice of the pie – hence the emphasis placed on such matters here at Speedtheory. Followed by rolling resistance – ie tyres (my wife is a bit sick of the ‘T’ word).

While transmission (chain, bearings) is a small part of the whole – this data is for an optimised setup. A less fussy setup usually has some very easy (good ROI) gains to be made so we won’t be ignoring this area.


For comparison I also ran the numbers for someone my size with a fairly typical triathlete position, dirty chain and poor tyre choice.

The proportions have changed a little but what is most noticeable is that the power required to go 40kph in this scenario has leapt by 47%. So there are big differences between a poorly informed setup and a OCD setup.

Thus, with the aim of introducing you to my nightmare the process of optimising your setup – the topics I intend to cover are:

  1. Body positioning
  2. Frame aerodynamics
  3. Wheel performance
  4. Handlebars
  5. Tyre selection
  6. Transmission
  7. Fuelling
  8. Helmets
  9. Clothing

I may break some of those topics into a couple of posts (I’m trying to keep them short) or add as I see fit.

If you haven’t read part 1 you can find it here.

Be sure to check in next week (same Bat time, same Bat channel*) as I discuss the often bewildering topic of frame performance.


*this is from a Batman TV series in the 1960s




Leave a Reply

Your email address will not be published. Required fields are marked *