Power Output

Warning: Nerd content (and probably inaccurate at that) below!

Just now I was pondering efforts at the Quarry Climb and was curious as to what amount of power is being put out on that climb. Yes, yes, have some time this morning...

Anyhow, so I start with basic fizziks:

1. Power = work done / time taken

2. Work done = force on object x distance object is moved

3. Forget anything fancy (as I don't know)... force on object = mass x gravity if you lift it in a straight line.

So gather some numbers: I weigh 80Kg (quiet accurate), the bike weighs 12Kg (sort of) and water, clothes, rest of it weigh 3Kg (which is probably an under estimate). The Quarry Track climb as measured by computer yesterday is 630m long and rises 84m, and I did it in 303 seconds.

3. Above is then (80 + 12 + 3) x 9.81 ('g' constant) = 931.95

2. Above is 931.95 x 84 = 78283

1. Above is 78283 / 303 = 258W

That sounds kindof poor, eh? But considering it doesn't take into account losses in the drive train, the 630m distance, the slippage on the ground, etc, etc, etc. maybe not so bad.

I then went a-Googling and found this page: http://bikecalculator.com/wattsMetric.html

Same numbers in there give an output of 298W... this sounds a bit better!

I also found this article: Lance Armstrong: Cycling Power

Armstrong sure can crank. During the final hour of a seven-hour stage of the Tour, he can pedal at an average of 400 watts. (Track racers have pushed it over 2,000 watts for a few seconds. The average cyclist can barely light a 100-watt lamp.)

Great, so almost 300W is above average which is nice to know, but I wonder how fast old Lance could get up that hill? After riding for 7 hours at 40-50Km/h don't forget! Mess around with the bike calc changing the average speed (Ok, so if you only change that it doesn't account for the fact Lance and his bike are probably lighter than my combo, but this is pure fun so don't worry about that) until the power output is 400 and you find that to average 10Km/h up there you'd be putting out 401W, and a 10Km/h speed would give a time of 227 seconds or 3m47s.

Nice time Lance, now here's something to aim at!