3 ms·

They’re not- 300W of effort is 300W of effort, it doesn’t have a bigger impact if the bike is heavier or not.

by fnbr 4y ago

deleted 4y ago
[deleted]
darkerside 4y ago
I wonder if that's really true on hills. Most people ride hills with more effort, pushing down on one pedal at a time. The bike speeds up and slows down much more with each pedal stroke. Compare to the flats where you have a smooth stroke and very consistent output. I could see all the mini accelerations adding up to a much larger energy expenditure than would be indicated by a spherical cow in a vacuum.
- wiredfool 4y ago
  Eh, it's really quite small, unless you have stupid heavy wheels (meaning, that the wheels are a significant percentage of the mass of the entire system). If the mass of the wheel is 100% located at the rim, the energy goes 1/2 into straight line energy and half into rotational. But -- if you slow down, you don't lose that energy, it just redistributes to gravitational potential. The flywheel effect from heavy wheels may actually help, as it tends to smooth out pedal strokes. The energy to go up a hill is just mgh - friction. Some cadences are less efficient than others (e.g. for me, standing is more power but lower efficiency), and bikes that are too stiff may not help you get the best rhythm. In a totally unscientific test -- I've got a 12kg Aluminum gravel bike, wide tires, rack, fenders. I've also got an 8kg carbon racing bike, skinny tires, aero rims, etc. They have similar riding positions (reach/drop), though the gravel bike has a wider seat, which is better for one climbing cadence. I usually ride the gravel bike these days, because comfort. Two weekends in a row, I did a 12x rep climbing workout (2.5 hours), one on each bike. First weekend, Road bike. It felt _fast_. Quick, lively, accelerated from the stoplights on the way to the hill. Second week, back on the gravel bike, grinding up the hill. Total ET difference: 5 seconds. Sure there are differences.

They’re not- 300W of effort is 300W of effort, it doesn’t have a bigger impact if the bike is heavier or not.

by fnbr 4y ago

They’re not- 300W of effort is 300W of effort, it doesn’t have a bigger impact if the bike is heavier or not.

deleted 4y ago

[deleted]

darkerside 4y ago

I wonder if that's really true on hills. Most people ride hills with more effort, pushing down on one pedal at a time. The bike speeds up and slows down much more with each pedal stroke. Compare to the flats where you have a smooth stroke and very consistent output. I could see all the mini accelerations adding up to a much larger energy expenditure than would be indicated by a spherical cow in a vacuum.

wiredfool 4y ago
Eh, it's really quite small, unless you have stupid heavy wheels (meaning, that the wheels are a significant percentage of the mass of the entire system). If the mass of the wheel is 100% located at the rim, the energy goes 1/2 into straight line energy and half into rotational. But -- if you slow down, you don't lose that energy, it just redistributes to gravitational potential. The flywheel effect from heavy wheels may actually help, as it tends to smooth out pedal strokes. The energy to go up a hill is just mgh - friction. Some cadences are less efficient than others (e.g. for me, standing is more power but lower efficiency), and bikes that are too stiff may not help you get the best rhythm. In a totally unscientific test -- I've got a 12kg Aluminum gravel bike, wide tires, rack, fenders. I've also got an 8kg carbon racing bike, skinny tires, aero rims, etc. They have similar riding positions (reach/drop), though the gravel bike has a wider seat, which is better for one climbing cadence. I usually ride the gravel bike these days, because comfort. Two weekends in a row, I did a 12x rep climbing workout (2.5 hours), one on each bike. First weekend, Road bike. It felt _fast_. Quick, lively, accelerated from the stoplights on the way to the hill. Second week, back on the gravel bike, grinding up the hill. Total ET difference: 5 seconds. Sure there are differences.