Originally Posted by
Maelochs
This gets us back to the weight debate .... yes a lighter bike is faster given the same applied power, but at what point is it meaningful. Save a gram? a pound? People will fight over that for dozens of pages ... in fact, they have.
Crank flex, frame flex ... luckily I am in that group of riders who need never fear these things.
The penalty for weight is easy to calculate. You pay a weight penalty for - increasing rolling resistance, increasing hub (and to a lesser extend BB and pedal bearing losses, chain roller losses and directly in terms of work done every time you go uphill.
Now rolling resistance is a very low percentage of total resistance at speed on good tires. Bearing resistance is far lower than rolling resistance. Added chain resistance is a small percentage of those low numbers (like 1%). Weight weenies will realize virtually no gain for their best efforts on flat ground unless: their tires are poor and/or the bearing and chain in a bad state of maintenance. Uphill is a different story. Steep enough and total weight of bike, rider, clothes and gear rules. A 10% change there means 10% faster. (10% of a 175 pound rider with 20 pound bike, 5 pounds of shoes and clothes and 2 pounds of gear and waterbottles is 20 pounds 3 ounces. Our weight weenie has work to do.)
Ben