Sub3-100k: Body and bike testing

In my quest to ride 100km in under three hours total time, I’ve been doing some testing of both my equipment and by fitness. I’ve completed a couple of test rides on the Planet X TT bike with varying success.

On my first test I averaged 34.5kph over 60km non-stop. Fast enough to hit my target, but I was approaching my limit. My average power was too high to be sustainable over the full distance and my body needed a break. I don’t think I could have held on for another 40km. Today I held a 35+kph average for 50km, so things are improving.

I’ve been optimising my position on the bike to be more aero – getting narrower and slightly lower – but it’ll take some time in the saddle to get used to holding the tuck for three hours. I am VERY out of practice! A new set of time trial bars with better adjustability means I can really dial that position to balance comfort, power and aerodynamics.

I’ve owned this old Planet X Stealth TT frameset since 2012, but the design dates circa 2006. The frameset is very dated compared to modern frames and while it looks aerodynamic, it’s actually not. The tube profiles are all wrong, it’s fully externally cabled, etc. My Canyon Aeroad is a more aero frameset and if I could fit clip-on aero bars to that, it’d make a pretty speedy setup (spoiler: they don’t make a set that fits).

I originally had an 11-32T cassette installed (11-speed). My thinking was it would enable me to keep it in the big ring for longer, but on flatter course it left me with “holes” in the gearing. The jumps in cog sizes meant I was either spinning too fast or grinding too slow on some sections. This is far less efficient and definitely cost me in speed and wasted energy. I switched this out for an 11-28T and the closer spaced cogs made an immediate difference. I was able to keep my cadence far smoother over small speed changes.

Moving forward, I need to build up time in the saddle, or more precisely time in the aero tuck. It’ll come down to the ability to put out power in the aero position over an extended time. I’d like to achieve the goal of a sub 3 hour 100km by the end of the year, or at least the end of 2021/2022 summer (southern hemisphere). I’ve mapped out a possible course I think will be suitable and continue to mull over my kit choices, pacing and other ride logistics.

It’s looking 100% achievable if I can bring it all together!

4 Comments Add yours

  1. nice little project. My TT days are well gone

    Liked by 2 people

    1. bgddyjim says:

      I never had TT days. Chuckle.


  2. Stuart says:

    This is something that has always been an item to tick of the list. I had a crack today off minimal cycling (average of 55km’s over previous 14 weeks), using a 10yr old road bike (Ultegra) with some clip on TT bars. No disc wheels. Had a great crit circuit to use, which was 2.25km, so just did laps of that. Surprised myself with a 2:46 at an average of 36.2kph.

    I think you just have to grit the teeth and have a crack. You may just find on the day that you have the will to get it done. It sounds like you have the training and kit to do it!

    Mine was all solo, with a couple of bottles of tailwind and 2 bananas. That was enough to get me through. No stopping heps!

    Liked by 1 person

    1. Casey Fields! Nice! I had to put the attempt on the back burner as the only feasible route for this around here now has major long term roadworks on it… 😔


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