Originally Posted by huhenio
Using PowerCalc to predict performance due changes in crank arm length.
So I got a hold of a set of 175’s in really good shape for 20$. The difference in the actual cranks and my older cranks is that the new ones have the five arm configuration, so changing rings for fine tuning my gear inch development would take 15 minutes versus impossible.
These are my findings using PoweCalc
Problem: 7% hill on 74 g.i. is a bit tough –
170 = 51.14 pounds @ pedals @ 52 rpm = 08.00 mph. – 291 watts @ pedals
175 = 51.14 pounds @ pedals @ 36 rpm = 11.22 mph. - 425 watts @ pedals!
I do not get it … I will use less pressure on the pedals, yet wattage increases.
In example 2 (175) you are turning less rpm but going 3 mph faster! No matter what you say, the two examples are not the same size gear. Power is work over time, and going faster requires more power.