4 ms·

> In fact bicycles are fastest off the line, since they produce max. torque at 0rpm (just keep weight on a pedal, release the brakes to go). I doubt a bicycle

by dpark 7y ago

> In fact bicycles are fastest off the line, since they produce max. torque at 0rpm (just keep weight on a pedal, release the brakes to go). I doubt a bicycle would actually cross the starting line before a high end bike or car would surpass it. A 180lb rider would produce about 90lb of torque at most (assuming 6” crank) and that’s only for the instant that the crank is parallel with the ground. A high end car would deliver significantly more than 90lb of torque instantaneously by dumping the clutch (or using launch control).

msandford 7y ago
You can produce torque in excess of your weight by using pedals that clip in and pedaling "circles" instead of "squares". When I was in good shape I figured I could produce torque much closer to my weight than half of it.
- hazeii 7y ago
  Did you forget to figure in the crank length? 180lbs at 6" is 90 foot-lbs of torque.
- dpark 7y ago
  The average rider probably cannot produce more torque than their weight that way. A quick search indicates that professional cycling sprinters can generate slightly over 100 ft-lb of torque. The average rider won’t be producing anything close to that. (Hard to find anything definitive, though.) If you aren’t standing up sprinting, you’re definitely not going to be getting anything close to your “body weight torque”.
hazeii 7y ago
Yes, but the car has to accelerate around 20 times the mass. Bugatti Veyron is listed as having the highest torque [0] at 1,106lb/ft but then it weighs over 4,000 lbs. Plus there'd a delay for the engine to rev up to peak torque before the launch (i.e. it wont produce 1,100ft-lbs at idle). Be interesting to test, but I'm not too practiced at racing Veyron's off the line on my bicycle. Having said that, I am very used to riding bicycles and (large) motorbikes around town, and from waiting for lights to change if I'm on a bicycle I'm generally first away even when motorbike riders are getting competitive (never mind cars). The advantage of the bicycle is generally only a few feet, of course. [0] https://en.wikipedia.org/wiki/Bugatti_Veyron https://en.wikipedia.org/wiki/Bugatti_Veyron
- dpark 7y ago
  Race cars don’t launch at idle. If you’re racing cars that are idling when the light turns green, then you aren’t racing their engines. You’re racing the driver’s disinterested reaction time. The Veyron might weight 20x as much as you and your bike, but has over 300x the power output of the best sprinters in the world. Given equal reaction time and equal interest in racing, I am doubtful your cycling advantage would last for more than inches against a high end sports car.
  - hazeii 7y ago
    I quite agree, as I've pointed out elsewhere although the bicycle is fastest away it's a short-lived advantage (I'm not discussion racing starts, so it's assumed all vehicles are starting from idle and reacting to e.g. lights changing). In a racing start, a well-driven torquey car (like the Veyron) will also launch faster than a motorbike - at least to start with. Once the speed increases, the acceleration drops and the motorbike can then use its superior power-to-weight ratio (which it can't fully use off the line). Eventually - once speeds are well into triple digits - a fast-enough car starts to catch up with the motorbike again (due to better aerodynamics).
corkscrew 7y ago
Track cycling sprinters (myself included) can produce over 300 Nm of peak torque (more than many mid range cars)
- dpark 7y ago
  I don’t think that’s accurate. But apparently the number is higher than I would have guessed, at around 230 for an elite cyclist. https://www.researchgate.net/publication/7528120_Torque_and_Power-Velocity_Relationships_in_Cycling_Relevance_to_Track_Sprint_Performance_in_World-Class_Cyclists https://www.researchgate.net/publication/7528120_Torque_and_...
jac_no_k 7y ago
/me commutes by bicycle, 32km each way, in traffic light hell that is Tokyo. I can get off the line faster then automobiles, they aren't racing / clutch dumping at the lights. Traffic is so heavy and with so many intersections, it's typically pointless for automobiles to race off the line anyways. As I filter past daily the same Pagani and Bugatti and LFA and Tesla S and NSX. :D

by dpark 7y ago

msandford 7y ago

You can produce torque in excess of your weight by using pedals that clip in and pedaling "circles" instead of "squares". When I was in good shape I figured I could produce torque much closer to my weight than half of it.

hazeii 7y ago
Did you forget to figure in the crank length? 180lbs at 6" is 90 foot-lbs of torque.
dpark 7y ago
The average rider probably cannot produce more torque than their weight that way. A quick search indicates that professional cycling sprinters can generate slightly over 100 ft-lb of torque. The average rider won’t be producing anything close to that. (Hard to find anything definitive, though.) If you aren’t standing up sprinting, you’re definitely not going to be getting anything close to your “body weight torque”.

hazeii 7y ago

Yes, but the car has to accelerate around 20 times the mass. Bugatti Veyron is listed as having the highest torque [0] at 1,106lb/ft but then it weighs over 4,000 lbs. Plus there'd a delay for the engine to rev up to peak torque before the launch (i.e. it wont produce 1,100ft-lbs at idle). Be interesting to test, but I'm not too practiced at racing Veyron's off the line on my bicycle. Having said that, I am very used to riding bicycles and (large) motorbikes around town, and from waiting for lights to change if I'm on a bicycle I'm generally first away even when motorbike riders are getting competitive (never mind cars). The advantage of the bicycle is generally only a few feet, of course. [0] https://en.wikipedia.org/wiki/Bugatti_Veyron https://en.wikipedia.org/wiki/Bugatti_Veyron

dpark 7y ago
Race cars don’t launch at idle. If you’re racing cars that are idling when the light turns green, then you aren’t racing their engines. You’re racing the driver’s disinterested reaction time. The Veyron might weight 20x as much as you and your bike, but has over 300x the power output of the best sprinters in the world. Given equal reaction time and equal interest in racing, I am doubtful your cycling advantage would last for more than inches against a high end sports car.
- hazeii 7y ago
  I quite agree, as I've pointed out elsewhere although the bicycle is fastest away it's a short-lived advantage (I'm not discussion racing starts, so it's assumed all vehicles are starting from idle and reacting to e.g. lights changing). In a racing start, a well-driven torquey car (like the Veyron) will also launch faster than a motorbike - at least to start with. Once the speed increases, the acceleration drops and the motorbike can then use its superior power-to-weight ratio (which it can't fully use off the line). Eventually - once speeds are well into triple digits - a fast-enough car starts to catch up with the motorbike again (due to better aerodynamics).

corkscrew 7y ago

Track cycling sprinters (myself included) can produce over 300 Nm of peak torque (more than many mid range cars)

dpark 7y ago
I don’t think that’s accurate. But apparently the number is higher than I would have guessed, at around 230 for an elite cyclist. https://www.researchgate.net/publication/7528120_Torque_and_Power-Velocity_Relationships_in_Cycling_Relevance_to_Track_Sprint_Performance_in_World-Class_Cyclists https://www.researchgate.net/publication/7528120_Torque_and_...

jac_no_k 7y ago

/me commutes by bicycle, 32km each way, in traffic light hell that is Tokyo. I can get off the line faster then automobiles, they aren't racing / clutch dumping at the lights. Traffic is so heavy and with so many intersections, it's typically pointless for automobiles to race off the line anyways. As I filter past daily the same Pagani and Bugatti and LFA and Tesla S and NSX. :D