Athletes update, Bike Fitting

Enhancing the Bike Fit experience

Here at Peak’s focusing on and delivering ‘real life’ successful bike fits with cyclists, TT racers and triathletes is one of our areas of expertise.

You can read in some detail, and watch some videos of the full Peaks bike fit experience here, on our web pages,  Bike Fitting the Peaks Way

I have now delivered over 100 fits in this past year or so.  Its been such a pleasure to read some great feedback from athletes who are telling me how much faster they are going, breaking PB’s and course records, or feeling more comfortable and faster for less effort!

So in that vein I am keen to build on further enhancing the studio fit for all athletes.  So with that in mind I have started to work with, and use the ‘Bioracer Aero system’ to support my studio fits.

What I want to do below is give you an introduction to this additional system I have started to use to enhance the Aero-bike fit, and give athletes some ‘real time’ information as we move through the process.

In the below video I will take you through, in some detail how I will use this system with my athletes and bike fit customers.  The link below gives you an idea from Bioracer, of how the system works on their website – Bioracer Aero system overview.

Below is how I will use the system, to enhance and support the key principles of a good bike fit.

What I am keen to stress here is that the Bioracer system does not replace wind tunnel or velodrome ‘live CDA’ testing.  These produce far more accurate actual CDA numbers as they calculate all variables to deliver a ‘real world’ CDA.  The Bioracer system assumes constants for a number of variables and ONLY measures the surface area, from the front of the rider, then estimates CDA on this basis.

Nevertheless, by utilising this as a tool to support the key fundamentals of a successful bike fit we can further validate and check what we have done.

So in the video you saw me testing my position, using two different helmets.  The Giro Aerohead (my usual race helmet), and a Lazer Victor helmet.

The below gives an ‘estimation’ of CDA using 2 helmets that I tested on myself in the video.

final analysis

What we can see, is that based on frontal area the system is suggesting that the aero head delivers a lower potential CDA and thus saves watts versus the Lazer.  (*just for reference as I only had one pair of hands here I captured the stills using the drawn outline and not, as I would in a live session, of the actual rider.  As you see in the Bioracer overview on their site!)

So let’s look at this in my ‘traditional’ way of fitting as well, and see if all this tallies.

Above is my traditional analysis, from the side.  What I’d be looking at here is:

  1. Key angles, two of which are indicated above
  2. Body shape
  3. Helmet & body integration
  4. Head and body height against key markers on the green screen (1-8 marked at 5cm intervals)

So, what do we think?

My view is to agree with the analysis of the software.   Fundamentally the positions should be the same, I actually think I am sat slightly further back with the Lazer helmet on which has affected my leg angle by increasing my hip height, and thus leg angle.  A side from that I am particularly interested here in the helmet, a number of things strike me in differences between the two:

  1. The integration between the Giro and my back is excellent, there will be very little ‘dirty’ slow air that will affect my CDA there.  This is less so with the Lazer
  2. The Lazer also sits slightly higher on the head so there is more of this in the wind, potentially affecting my CDA.

There are two other things we can do within the system.

The first is we (as in the video) are able to view what live changes we make and how they stack up , in potential watts cost or benefit, against the ‘reference pose’.  So for example we could work on your tuck, moving forward or back on the saddle or width of your arms.  We can then see, simply by a colour indicator if these are potentially better or worse for your position than the base line, reference position.

Once we have ‘nailed’ the position, there is an option to go into ‘training mode’.  Here you can deliver a training session, practicing holding the position to see how realistic it can be when you are ‘on the rivet’ in a race type situation.

So The Bioracer Aero system is a great additional tool to help optimise the perfect studio fit.

As I talk about in the video a studio fit, is in my mind, the most efficient, initial way to help you nail your position.  Once this is optimised as good as we think it can be, then, at that point would I recommend looking at some live testing to find those small, final incremental gains.  The studio fit does not give you 100% accurate real life CDA numbers that a velodrome or wind tunnel session will give you.  Although the benefits I do think make it worthwhile in the following situations:

  1. An athlete who is new to TT / Tri bikes and has not been set up before
  2. Experienced athletes who are looking to aero optimse a previous bike fit they may have had through a  RETUL or similar system
    1. The RETUL, and similar systems, offer excellent biomechanical set ups.  In my view their limitations come when we start to consider the importance of aero dynamics.  We know form previous posts of mine such as Just how important is it to be aero? and many others from other specialists , that an aero dynamic position is a compromise of perfect biomechanics & aerodynamics.  Losing 10W power output in your aero position MAY be better than having access to those 10W, as the aero gains outweigh the loss of power.
  3. If you have bought a new TT / Tri bike – what is important here is that you cannot just overlay the old dimensions onto the new bike!  Stack, reach, frame geometry, saddles and other components will mean the position will not be the same!  Don’t make this mistake!
  4. Any athletes who may never have been fitted before who is trying to replicate ‘what the fast guys look like’.

ONCE you have optimised all parts with a quality studio fit, and then you are in a position such as mine, now may be the time for a wind tunnel or velodrome session to work on the tiny increments.

In the below table I try to (pragmatically) lay out the pro’s and con’s of the two systems

studio v tunnel

In the above, as an example, we cannot in a studio fit tell you how many watts a new skin suit, trip socks, or even wheels will give you, a ‘live session’ can do this – But what we do know from manufacturers and independently published data is the increments these will save.  So as such ‘ we know’ that XX wheel will save you 5w, and can then calculate a theoretically CDA (or in reality CRR- rolling resistance) benefit.

In summary the decision is yours to be made, my advice would be to optimise as much as you can via a studio fit, or even doing your own work.  Once you are in this position, then, if you are keen on saving those further few seconds, look to a wind tunnel or velodrome fit.

Hope that helps and I’d love to see many more of you for a studio fit!



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