40k Time Trial

Two milestones I'd like to hit in my multisport fitness are doing a 40km time trial on the bike in under an hour, and running a 5k under 20 minutes. Neither of these feats are all that extraordinary in and of themselves, but they've given me good goals to shoot for within each sport. Once my triathlon season was over, it was time to focus on other goals, and these are what I've set out for myself.

Like last year, I plan on doing a run focus this fall. That will culminate in some sort of race. Meanwhile swimming, when I start up again, will be just once a week and biking will be for pleasure only - no more grinding away on the trainer in the basement and no more suffering through intervals. So... now's the time for me to take a stab at the 40km time trial, while I'm still carrying some bike fitness from the tri season.

My parents and in-laws live in Perth, and as luck would have it, the stretch of road between Perth and Franktown is perfect for time trialing. Wide, paved shoulders, no major hills, pavement in good conditions, and just over 20km long. This is where the Almonte Bicycle club does their 40km time trials, and that's how I discovered this route.

So on saturday I set out to try to go sub-1 hour. I knew this was going to be hard, but if nothing else would give me a feel for what a 1 hour threshold effort really feels like and be a good learning experience I can apply to subsequent efforts. The result was a pretty-damn-close 1:01:22 - I made several errors that collectively cost me enough time that I feel like I probably could break one hour if I made another run at it. Not this year though. It's onto my run focus.

Interesting data from this endeavor though. I graphed speed vs. power for this TT and my 3 races this year, and it looks like this:

You can see that I pushed a lot more power during the TT (nice not to have to run afterwards), and this translated into a lot more speed. Interesting that my speed was pretty similar in each of the 3 races. The biggest difference was Smiths Falls vs. Nationals, which produced a variance of only 0.6 km/hr, on a power difference of 20 watts. I pushed another 20 watts higher than this in my TT, but saw an increase in speed of 2.5 km/hr. I attribute this to some different choices in apparel as well as being more diligent holding an aerodynamic position (something I struggled with in races this year).

The impact of aerodynamics is shown even more starkly when I looked at a ride I did earlier in the week with my normal training set-up rather than my race set-up. I did a 20km sort-of-TT (not really going all-out but seeing what kind of wattage I could hold) and averaged 37.4 km/hr on 246W. Compare that with the 40k TT where I averaged 39.2 km/hr on 237W. So almost 2 km/hr faster on nearly 9 less watts. Gotta work on holding that head position better in races next year.