Power, Aero, & Comfort: Choose Three.


This time trial position is my fastest yet. I’m comfortable enough to ride long time trials; I maintain more of my road bike power than ever before;  and my CdA is down to 0.208.  Win, win, win.  Yet if I looked at this position for the first time, I’d think there’s no way it’s as fast as my past positions.  It’s visually too high in front.  This being said, it is not always about finding the most aero position as much as it is about building a sustainable and powerful position that maximizes the aero potential it offers simultaneously.

A Brief History of My Aero Position

A little history first and then some tech for the aero geeks.  I was happy with my 2021 position which got me back on the track bike and racing at Nationals. I was able to go faster at both the 3k and 4k pursuit events, but I also wanted to get back into longer time trials.  This position was not comfortable enough to ride that long.  Despite going faster, I’ve always compromised some power in this position compared to my road position.  I wanted to build a position that allowed me to minimize the compromise of each variable.  I set off into testing in the summer of 2022 and found some comfort gains on my track bike.  I spent this past summer of 2023 testing more than I ever have. I looked through my drawer of field testing results and I tested ten separate days assessing seventy positions (yes, 70) total since May.

Field Testing Aero Protocol

When field testing, I used the Chung half-pipe method to test which I’ve found to have even tighter accuracy and repeatability than wind tunnel testing. By the end of the season, I had reduced my CdA on my Cervelo P5 TT bike down to 0.208 and, finally(!),went under 19 minutes on my local 9.8 mile time trial.  This was a goal I’d been chasing for nine years.  It felt great to achieve it, especially considering I’m not getting any younger.

All aero tests are important.  However, if there is a key field testing moment in recent years it was the day I spent testing very high aerobar positions. At first, my drag got worse as I went higher, but then it leveled out as I went higher still.   And then something unexpected happened – my drag started decreasing again when I went even higher. I found a position in late 2022 where I felt much stronger and was nearly as aerodynamic as my lowest position. I felt somewhat reborn as a time trialist and looking forward to finding gains this summer and returning to the racing scene.

Some small changes proved to be big gains and plenty of changes you’d expect would be faster but weren’t. Many tests showed no gains or were inconclusive but that’s expected and simply hold on to what works and move forward. It helps that I’m on a faster bike, wheels, skinsuit, tires, shoes, shoe covers, and helmet than I used in the past. The rest of the gains were the position and increased power.

When Aero Reality Throws You a Curveball

It often surprises me when a change you’d think is faster, actually slows you down. We captured an example in the photos below.

The first picture is my fastest position from the ones referenced above (CdA 0.208).  The second position pictured shows me tucking my head down (CdA 0.212). That 0.004 increase in CdA is around 6 watts at 31mph for me. In this position, I’m literally faster when my head is higher.

To verify, I tested this position change exclusively back and forth for multiple days.  It took me awhile to believe the results. This is a classic shrug where I hold my chin lower and look out of the top of my eyeballs. It even gets quieter with far less air hitting my face with my head down which makes the results even harder to believe. The gain is greater with the visor of the helmet removed – which turned into a vital change for keeping me cooler on hotter nights – an overheating topic for another day.

While I’d never tell anybody to simply hold their head up in the air when in a time trial (in the interest of full disclosure, I tell the majority of clients the opposite), the data proves out that doing just this is faster for me.   This is why riding position needs to look at, and test, the individual’s needs and not be based on assumptions. This is particularly crucial when you are trying to save seconds.

­Reduced frontal area almost always correlates to reduced CdA.  Until exceptions like this, when it doesn’t.

Other Interesting Aero Field Testing Results

Another part that took a while to sort out involved the testing I did on saddle height this year. I found if I lower both the aerobars and saddle 1cm from the above position my CdA is the same (0.208), but I lose a little power. However, if I raise both the aerobars and saddle 1cm from the position above my CdA jumps to 0.213.   However, it gets even stranger – if I raise only the aerobars 1cm but leave the saddle height alone the CdA jumps to 0.218 – 15 watts slower!   Fortunately, my power and comfort are fine at the moment, so I don’t need to go any higher.

UCI Limits for Taller Riders in the Aero Position

Under the new rule which, thankfully, grants cyclists between 1.8m to 1.89 meters tall an extra 3cm of reach over the prior rules, I’m currently at the UCI limit of 83cm of horizontal reach to the end of aerobar extensions.  The prior reach limit was 80cm and thus there was no reason to test my UCI position longer than this.  Interestingly, once I started testing over 80cm not much happened until that last centimeter.   That last 1cm from 82 to 83cm was a big one.

Other places I found gains this summer included clamping my hands together and rotating my thumbs forward, similar to what I’d done a few years ago.   I verified that wider elbow pads are slower for me, but narrower elbow pads than what I had been riding weren’t any faster.  I’ve had inconclusive results testing aerobar extension angle and thus I still currently run a relatively flat forearm angle, which is comfortable and familiar to me.

My 2023 Time Trial Nationals Results

I went to Time Trial Nationals this past summer for the first time in six years and finished 2nd. I knew ahead of time that with 1100 feet of climbing in 18 miles the course was pretty hilly this year (about double the climbing of our local time trials). I was happy with how I paced it in the heat and hills and felt I couldn’t have gone much faster. I was happy with my time.   This being said, the trouble is when you bring a 4.2 watts/kg knife to a gunfight on a hilly course against 5.5+ watts/kg guys there’s only so much bleeding your higher watts/CdA is going to stop. Cheers to flatter time trials and velodromes to the more gravitationally challenged among us!

We’re always happy to talk bike fitting and tech, just contact us.

P.S. Not only do we have a great bicycle mechanic in our Peabody, MA location in Stephen Kozowyk, we also have a professional photographer. He set up the shoot perfectly.  Thank you!


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