Tuesday, July 28, 2009

Hot riders

Most of us on the trip are pretty serious riders, and several are Masters or Category 2 or 3 racers. The racing license categories go from Cat 5, the lowest, up to Cat 1 or Pro (for those that get paid and do it full time). So many of the people had power meters on their bikes to measure how hard they were working, and many had heart rate monitors and GPS units on their handlebars.

The power meters measure how much power you are putting into the bike in Watts. I keep about a 200 Watt average while climbing, a pace that lets me keep going for a long time without getting out of breath or my heart rate going above 145 or so, though my heart might be pounding a little at the higher elevations where the air is thinner. Some of the racers in the group can average in the high 200's on the climbs, but I can only do that for the shorter (mile or so) climbs where I'll let my heart rate go up to 160-175.

The human body is about 25% efficient riding, so that means that it needs to burn 800 watts to put 200 into the bike. The other 600 watts is heat! Imagine the heat from ten 60 watt light bulbs and you can understand why we can ride up mountains with snow on the side of the road yet still be in short sleeves. On flatter roads you generate a cooling breeze, but not so much at the slower speeds we go uphill, so the colder air at the top was often welcome. But as soon as we stopped on many of the mountain passes we would need to put on long sleeves, vests, jackets and full gloves to hang out there and for the descent. Then part way down the mountain you need to take it off again as the temperature goes back up. Ventoux was hot, but most of the passes in the Alps were pretty cold. Even with all of the layers on, my bike had a noticeable wobble on the Grand Saint Bernard descent into Italy because I was shivering so hard in the cold mist. Then at the bottom you are looking for a cold drink again...

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