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My sprocket size and ratio research.

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My sprocket size and ratio research.

Old 02-03-23, 07:56 PM
  #51  
beng1
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By coincidence I was looking in a book on bicycling from 1982 with a lot of technical information in it and it did state that if you have a large set of sprockets and a small set which both give the same ratio, the larger diameter set will put less tension and wear on the chain, which would also give the lower friction one member responded with above.

As far as crank length goes for cyclists, lots of individuals have opinions, whether they have a lot of experience with cycling or not, they are still individuals with opinions. I have no opinion on the subject, just passing on what the laws of physics and engineering say about it. There has never been a scientific research done on the length of bicycle cranks using riders of different sizes, they have all been done using the same cyclist/s testing different length cranks, not different length cyclists testing the same or different cranks. So outside of what engineering and physics have to say, I will never be interested in individual opinions on the subject, at all.
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Old 02-03-23, 08:06 PM
  #52  
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Originally Posted by ofajen View Post
On the whole, being large and tall is a disadvantage in cycling. For similar level of training, W/kg scales with an exponent of about 0.7. The work against gravity when climbing obviously scales with an exponent of 1.0. Thatís why smaller, lighter riders tend to be the ones who are the fastest climbers.
Larger riders have a smaller relative advantage on level ground, since the increase in frontal surface area scales with an exponent a slight bit less than 0.7.Otto
Sure, in whatever world cycling is all done uphill large riders are at a disadvantage. And only in long road races that involve hills will the large rider be at a disadvantage. Most cycle racing is not done at a pro level, and are short TT style races that are relatively level. I can leave my house and ride east or west for hundreds of miles and the ride will be near level, if I go north it will be downhill until I hit the great-lakes, if I ride south it will be uphill for a bit until I get to the watershed then it will level out. So saying a rider is at a disadvantage because of their size means nothing unless you are talking about pros, which make up a small fraction of one-percent of the cycling public. When you have something to say that applies to a large part of the cycling public, then you might be worth listening to.
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Old 02-04-23, 09:17 AM
  #53  
eddy m
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Originally Posted by beng1 View Post
Most cycle racing is not done at a pro level, and are short TT style races that are relatively level.
Not around here in Upstate NY. Most races at all levels are hilly road courses. There hasn't been a sanctioned TT or even a crit in years. Even club rides become competitive climb fests. Gravel rides are the new big thing here, and small guys have even more advantage because descending speed is limited more by road conditions than aero drag, which makes it harder to close gaps. Big guys are definitely at a disadvantage.

Ask me how I know.

em
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Old 02-04-23, 09:30 AM
  #54  
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Originally Posted by beng1 View Post

As far as crank length goes for cyclists, lots of individuals have opinions, whether they have a lot of experience with cycling or not, they are still individuals with opinions. I have no opinion on the subject, [b]just passing on what the laws of physics and engineering say about it. [\b]
From your previous posts it appeared that you did not fully grasp the physics of long vs short cranks. But otherwise I would agree.
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Old 02-04-23, 09:33 AM
  #55  
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Sheldon Brown was right about most things, and he was right about gear ratio and crank length, however poorly he explained it. Crank length is a personal preference, and even riders with identical body dimensions may want different cranks, dependong on the strength or flexiblity or training. But really, cyclists obsess over the difference between 170 and 172.5. The difference between 165 and 180 is only 9%, or less than one gear change.
Get over it.

em
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Old 02-04-23, 09:50 AM
  #56  
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Originally Posted by eddy m View Post
Not around here in Upstate NY. Most races at all levels are hilly road courses. There hasn't been a sanctioned TT or even a crit in years. Even club rides become competitive climb fests. Gravel rides are the new big thing here, and small guys have even more advantage because descending speed is limited more by road conditions than aero drag, which makes it harder to close gaps. Big guys are definitely at a disadvantage.
Ask me how I know.em
And then we have the fact that the rider in the TourDeFrance who has won the climber's contest has only won the overall tour 12 times in total. So much for small climbers being at an advantage. Have another try though....
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Old 02-04-23, 10:04 AM
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Originally Posted by beng1 View Post
And then we have the fact that the rider in the TourDeFrance who has won the climber's contest has only won the overall tour 12 times in total. So much for small climbers being at an advantage. Have another try though....
All the winners are exceptional climbers. Think of Armstrong's ride when he was knocked over by a spectator on a climb. He didn't win KOM but he and went on to win the stage and the whole race.
Guys going for a GC win don't risk crashes to take sprint points, and they don't waste energy going for KOM. Those things are gifts to rookies and second tier riders. Wallk around the start of any pro race and you'll see that they're all small guys.
Maybe learn something about racing before you comment on it.

em

Last edited by eddy m; 02-04-23 at 10:15 AM.
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Old 02-04-23, 10:30 AM
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Originally Posted by eddy m View Post
Sheldon Brown was right about most things, and he was right about gear ratio and crank length, however poorly he explained it. Crank length is a personal preference, and even riders with identical body dimensions may want different cranks, dependong on the strength or flexiblity or training. But really, cyclists obsess over the difference between 170 and 172.5. The difference between 165 and 180 is only 9%, or less than one gear change.Get over it.em
What you, and Mr. Brown missed, is that sure, you can get the same torque as a longer crank has by shifting to a lower gear ratio, but at the same max pedal rpm any rider is capable of, they will not be able to go as fast. That is what higher gears are for, going faster, and if you can put longer cranks on a bike and pedal them at the same rpm because you are a tall rider, then physics and engineering agree you have more power and speed, just as they say a longer lever will always give the same weight more power. You are welcome to try again though.....
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Old 02-04-23, 10:32 AM
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Originally Posted by PeteHski View Post
From your previous posts it appeared that you did not fully grasp the physics of long vs short cranks. But otherwise I would agree.
Nice statement, except that any five-year-old can tell someone the same thing, so unless you point something out specifically or add some logic, common sense or facts to your statement, your statement has no more value than that of a five-year-old.
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Old 02-04-23, 10:34 AM
  #60  
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Originally Posted by beng1 View Post
What you, and Mr. Brown missed, is that sure, you can get the same torque as a longer crank has by shifting to a lower gear ratio, but at the same max pedal rpm any rider is capable of...
I'm aware of that, and I don't think Sheldon missed it either. You are just reading things into that aren't there. There's no need to be snotty about though, but I assume that's just your nature.

em
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