Pacing: How to pace for 40K
Cycling a sport of pacing. End of story. If you're doing the third pedal stroke of a century, you are already preparing yourself for the pacing it requires. If you're going to try a heroic last-lap attack in a criterium, you better know how long and hard you can put out that maximal effort. If you're going to beat the hour for 40K, you should know what riding at threshold feels like.
An overlooked art in cycling is pacing. Proper pacing is done by feel. Yes, you heard me. It's done by feel. There is no power meter accurate enough or course consistent enough to pace off the numbers (perhaps with the exception of world-class indoor tracks). Don't get me wrong. I race with a power meter, heart rate monitor and speed indicator (mostly for post-race analysis). I'll also have a stopwatch on my wrist so I can see my time splits (math done on the fly). Time splits can tell you how far above or below you are from your goal, the odometer can give you an idea of how long you have to go (this can help mentally) but from one second to the next, you're going to have to rely on your intuition and listen to your body. The only way you can get good at this is practice.
Before your 40K attempt, you should have at least one 40K effort under your belt. If your area does not permit it, find a flat course that you can ride the TT bike on non-stop for at least 10 minutes. After 10-15 minutes, the effort level is very similar to what you'll be doing for an hour. Go out and see how it feels.
A few quick tips: Start slow. Start slow. Oh, and start slow. I'll often push a 55X15 gear on the flats in TT's, and I'll start in a 55X17 on the start line. I do not sprint up to speed. I "rock" my way up to speed, only a little quicker than if I were to start from a stoplight on a training ride. For a 40K TT, I will literally go 90% of my threshold for the first 4-5 minutes. If you hold back in the beginning you can generally make up a LOT more time later.
If you're feeling the burn before 1/3 of the race is over, you are going too fast. If you finish the TT and after 5 minutes you feel like you could do it again, you went too slow. More often than not, people go way too hard in the beginning of time trials.
Between that critical first few miles and the finish line, I am paying most attention to my breathing, pedal stroke, and posture. I somewhat keep track of my speed and power, but those are secondary to the aforementioned.
My best time trial I did in 2010 was the 20K TT at Fiesta Island in September. It's a windy circuit with three laps. My splits? 8:50, 8:40, 8:31. I did not feel the "burn" until about halfway through the race. I'm serious. I really held back in the first lap and let my heart rate come up and let my body acclimate to the effort. I set my new personal record by 25 seconds!
1) Practice your starts and coming up to speed
2) Go ~90% for the first 2-3 miles
3) Practice your sustained effort level.
Feel free to email with questions