Small Changes Equal Free Speed: A Mini Experiment

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If you are interested in improving your performance, there are many things you can do, and in general, it is better to focus on improving your fitness than to worry about anything related to equipment.  Typically, for the first few years, you don’t need to worry too much about the details of the training to improve, as long as you are consistently swimming, biking, and running.  The more you train the faster you go (assuming you are absorbing the work with proper recovery, but that is another discussion.)

However, if you’ve been in the game for a few years (generally ~3 or more), fitness gains will be harder to come by from just simply training.  You will need to get more specific with the training and get much more structured in terms of the type and intensity of the sessions.  In addition, this may be the time to start considering other things you can do to get faster.  One such area is making some simple, basic equipment choices for improvement, which can typically be applied to the bike portion of the event, where aerodynamics have a large role in your speed.

In terms of basic physics, the speed at which you move on a bike is related to a few basic quantities: the power you produce, the resistance from air/wind, and the resistance from gravity.  It is a simple balance, the more force you produce to push the bike forward (i.e. putting power into the pedals) and the less resistance you have from wind and gravity, the faster you will go.  “Free speed” can be gained by reducing resistance and not needing to increase power.

One of the equipment choices to be made is how to carry hydration on your bike.  The typical setup includes 1 or more bottles on your bike frame, 1 or more bottles mounted behind your seat, and some type of hydration system in between your aero bars, a so-called BTA (between the arms) system.  Companies will test these types of bottle placements and systems in the wind tunnel and often publish data.  However, I have always been curious how much this really holds up in real race conditions.  Now I have a race-specific data point.

My previous setup had a typical, round bike bottle on the seat tube of my frame and during races, I would use a Profile Design “Aero” bottle between the arms.  However, this season, I made 2 changes.  BTA systems that don’t hang down below your aero bars are supposed to be faster by creating less drag, so I decided to try one this year, opting for the TorHans Aero Z.  The other change I made is using a more aerodynamic setup on my frame, going away from the round bottle, and choosing the TorHans VR bottle to “clean up” the air moving around the frame and reducing the resistance from the wind.  In theory, I should go faster for the same effort or power.

As a side note, this is also a great reason to have a power meter, because otherwise, you have no idea how much work you are actually performing to result in any given speed.  Using the data from my power meter, I have a really good comparison of two different time points, the first at the QuarterMax triathlon in 2012 and the second at the same race in 2015.  My bike setup was exactly the same except for 2 changes: the TorHans Aero Z and the TorHans VR bottles.  You can see what they look like here:  And here is a picture of what they look like on my bike.

Race Rig Setup

Race Rig Setup

The results of this little experiment break down like this:

Year Time Average Power Normalized Power
2012 1:07:56 260 278
2015 1:08:04 252 266


While my bike splits were within 8 seconds of each other, my average power and normalized power were different.  Using the 2 new bottles, I rode 8 watts less.  However, in looking at the norm power, it was 12 watts less.  While I don’t have quantitative data to prove it, I can say the conditions were quite similar, at least by recollection.  Mid 70s temperature with low to moderate wind.  Plus it is a loop course so the wind would be coming from different angles throughout the ride.  There are certainly a multitude of factors involved, but the data certainly suggest that these 2 simple, cost-effective changes, saved me in the vicinity of 10 watts!  Depending on the course selected, BestBikeSplit ( tends to estimate 10 watts is about a 3-4 minute savings for a half IM distance ride and 6-8 minutes over an IM distance ride.  That is a HUGE savings resulting from a simple, cost-effective change to bike equipment and no change at all to fitness. Now certainly one question is why didn’t I ride the race at the same power or even higher than I had before.  There are several possible explanations, but the likely answer to that question (I hope) is that I just don’t have the same depth of fitness (yet) that I had back in 2012. However, on the bright side, I rode the same speed on less effort, and speed is ultimately what counts on the clock!

While this is a very small sample size, and somewhat anecdotal, it does suggest that small changes can make a large impact, and if you are working on getting closer to the “pointy end of the field,” details can certainly make a difference…

Race smart!

Coach Jon

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