25 Miles is a Different Experience

This week’s time trial at RAF Weston on the Green was a little different to usual: the main event was over 25 miles instead of just 10. Here is the record of my 25 mile ride on Strava:

Official timekeeping clocked me at 1 hour 15 minutes 57 seconds. Read on for some thoughts on pacing.

Pacing is difficult to learn; to try and help myself I made separate segments on Strava for the downhill and uphill sections of the RAF WotG course. I think that the fastest way to ride the lap is to put more effort into the uphill parts than the downhill ones; looking at them as separate segments allows me to see how well I am doing this, as well as inspect what others are doing to see if I can derive some best-practice.

So how am I riding it? Here is a lap-by-lap breakdown:

Down Up Delta Total
Time Power Time Power Time Power Time Power
3.37 168 3.52 239 0.15 71 7.29 205
3.27 187 3.56 225 0.29 38 7.23 207
3.33 189 4.01 218 0.28 29 7.34 204
3.32 186 4.05 221 0.33 35 7.37 205
3.32 210 4.06 219 0.34 9 7.38 215
3.32 191 4.04 224 0.32 33 7.36 209
3.34 178 4.10 222 0.36 44 7.44 202
3.28 191 4.14 209 0.46 18 7.42 201
3.33 191 4.05 213 0.32 22 7.38 203
3.27 187

I think that the best-paced lap in that table is the first one: power is under the overall average so it should be sustainable, and it I had done the same thing in every subsequent lap I would have saved over a minute, which would have given me a time under 1 hour 15 minutes: an important milestone I have yet to achieve. I was unable to sustain that pace because it felt too slow to me on the downhill part and I was not convinced that I was earning back more time on the subsequent uphill section. Now I have analysed the data and found that my feeling was not a good guide to pacing I can hope to do better on the next ride.

Let’s look at what Cerys did on the same day:

Down Up Delta Total
Time Power Time Power Time Power Time Power
4.12 263 5.21 171 1.09 -92 9.33 211
4.13 215 5.37 162 1.24 -53 9.50 185
4.16 200 5.44 146 1.28 -54 10.00 169
4.09 239

Of course the power numbers are only estimates as Cerys doesn’t (yet) have a power meter. However it is quite telling that the time differences are so large. I’m quite surprised because for this ride she was using a 34-tooth chainring which means if her speed gets to 21mph she can no longer pedal rapidly enough to catch up to the freewheel ratchet.

Happily we also have data from her first-ever ride on this course, for which she used a 50-tooth chainring:

Down Up Delta Total
Time Power Time Power Time Power Time Power
4.11 265 4.53 236 0.42 -29 9.04 249
4.25 244 5.05 203 0.40 -41 9.30 222
4.26 232 5.08 212 0.42 -20 9.34 221
4.14 259

As we can see this ride is a lot more consistent lap-to-lap, the time spent on the uphill section is hugely reduced with only a minimal increase in time spent on the downhill section. Obviously conditions were different, furthermore it was her first ever time trial. It remains her personal best, and also the only one after which she told me she felt she had kept too much in reserve and could have gone harder.

Next time, incidentally, she should be equipped with a 42-tooth chainring.

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