Well, I finished the first cyclocross race of the season. It was great fun and a great workout. You can see some of the pictures my wife took here. I finished 15th out 16 men. I was also behind both women and the junior who competed in the C-Race. I did manage to complete 4 laps which was my primary goal for this race. I was also probably the largest competitor at 6′ 2″ 230+ lbs. I just found this:
He posited a 5 kilometer, 7% grade. That’s a good, stiff climb. The legendary Stelvio climb averages 7.5%. He further assumed a rider who can kick out 250 watts. A 160 pound rider will take 19 minutes and 21 seconds to get up the hill. Every 5 pounds added make the trip up the hill take 30 seconds longer.
That means each added pound adds 6 seconds to the time it takes to get up this hill. That is only 6 seconds on a stiff, 20 minute climb.
So, given our roughly 4-pound range from a full steel bike to a super-light carbon or aluminum bike, the time difference up this hill would be 24 seconds from best to worst.
But, most weight conscious people aren’t bringing their bikes down to 15 pounds because down at that weight, the handling gets very sketchy. 17 – 17.5 pounds is the normal range. The real discussion is about 1.5 to 2 pounds.
The performance advantage of a lighter bike is greatest when the hill is steepest. What happens as things flatten out? Then, as the speed of the bike increases, the resistance comes from the wind, tire rolling resistance, bearing drag, etc. Those 6 seconds/pound grow ever smaller.
The variations in body weight, however, being so much greater, make large difference. If that same 160 pound-250 watt rider were to be 220 pounds, he would come in 6 minutes, 10 seconds later.
This is actually encouraging to me. As all these smaller riders have a 9 minute advantage over me if we both output equal power in a 30 minute race. So now if I factor that time in to the results, I will have to see how I would place. I will be thrilled if I have similar power outputs to my much lighter competitors.