Hilly Long Time Trials – How many seconds can pacing gain?

Is it possible to save minutes just by pacing optimally? Without getting fitter or more aero? Let’s take a look…

Two laps of this Strava segment are in question today – the aim is to try and get two laps done in as close to 2 hours for 300W as possible with an 85kg rider who is moderately aero (with a cda of 0.24). Let’s see what we get when we plug the course into myWindsock.
We start out with a time of 2 hours and 10 minutes for a normalised power of 210W. Now we can take a look at the power-time relation for this run.
Here is our flat power curve, the spikes are just to get moving again on the steep gradients at the bottom of the descents. The climbs and descents are the main reason for pacing being so important with there being around 1000m of elevation in the whole TT. Let’s take a look at the breakdown of that elevation to come up with some pacing rules…
The majority of the climbing on this course is at less than 3 percent, the sort of climb you might go up in the big ring. At this point it’s important to remember to invest more energy into steeper sections where the rider will be moving slowest – the best plot to look at this is “Where Power Matters Most”.
The orange bars represent areas on the course where the return on investment of energy is greatest – you’ll notice that these are pretty much all on climbs where gravity is the main source of resistance vs air resistance. This is because speed increases more at lower speeds (so your speed might double for double the power, rather than increasing one or two percent if you double the power at high speed). Let’s take a look at the resistive force breakdown on this loop…
We want to invest “over” our average pace in 33.7 percent of the ride – when we are fighting gravity. As here, we get more return on energy investment.

The aim – get as close to 40kph as we can…

39.7kph was as good as I could get without getting more aerodynamic. I actually reduced aerodynamics allowing for sitting up on the ascents. This was a achieved with the following power profile…
For this, we set a hard cap on power at 350W, dropped it down to zero watts when descending and riding the flats at just under 300W. The result is a two minute time saving for an average power that’s 10W lower, aerodynamics being around one percent slower and for a normalised power that’s 3W lower. So, the result of pacing more effectively is a two minute saving at a lower power and being less aerodynamic.

Pacing your efforts is much easier with myWindsock. It’s the only place you can virtually test pacing strategies without having to ride them on the road. Pacing can make a bigger difference than anything, especially on rolling and sporting time trial or triathlon courses. It’s not just for solo efforts though, myWindsock can also help you spot the best place in a road race to attack! Sign up here.