Wheelchairman
02-11-07, 01:25 AM
Is weight the only factor? Does materials and the shape of the link matter?
Awaiting reply!
Awaiting reply!
Bicycle Mechanics - What dictates a chain's efficiency?
Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.View Full Version : What dictates a chain's efficiency?
Retro Grouch
02-11-07, 04:27 AM
Just what do you mean by efficiency? Are you talking about power loss during the transfer process or you asking about shifting crispness?
Either way I'm interested in what the engineering guys are going to have to say. If we're lucky maybe Sheldon will weigh in on this question. I honestly don't know so anything I say would just be a guess.
Either way I'm interested in what the engineering guys are going to have to say. If we're lucky maybe Sheldon will weigh in on this question. I honestly don't know so anything I say would just be a guess.
Wheelchairman
02-11-07, 04:49 AM
Whoops. Should've been more specific :o
I'd like to think that shifting is a distant 2nd on my priorities.
I guess I'm talking about power lost during transfer, but from a feeling point of view, I'm talking specifically about ease of pedaling. You know what I mean. A chain that gives the impression that you could pedal on at X cadence forever without a break.
Is this dictated just by the weight, or does shape and materials contribute as well?
I'd like to think that shifting is a distant 2nd on my priorities.
I guess I'm talking about power lost during transfer, but from a feeling point of view, I'm talking specifically about ease of pedaling. You know what I mean. A chain that gives the impression that you could pedal on at X cadence forever without a break.
Is this dictated just by the weight, or does shape and materials contribute as well?
iNewton
02-11-07, 05:45 AM
Whoops. Should've been more specific :o
I'd like to think that shifting is a distant 2nd on my priorities.
I guess I'm talking about power lost during transfer, but from a feeling point of view, I'm talking specifically about ease of pedaling. You know what I mean. A chain that gives the impression that you could pedal on at X cadence forever without a break.
Is this dictated just by the weight, or does shape and materials contribute as well?
Chain offer extremely diminishing returns, the thing that helps the most will be constantly keeping the chain well lubed and clean of dirt. Helping both the chain's longevity and it's efficiency.
I'd like to think that shifting is a distant 2nd on my priorities.
I guess I'm talking about power lost during transfer, but from a feeling point of view, I'm talking specifically about ease of pedaling. You know what I mean. A chain that gives the impression that you could pedal on at X cadence forever without a break.
Is this dictated just by the weight, or does shape and materials contribute as well?
Chain offer extremely diminishing returns, the thing that helps the most will be constantly keeping the chain well lubed and clean of dirt. Helping both the chain's longevity and it's efficiency.
ryder47
02-11-07, 08:13 AM
Whoops. Should've been more specific :o
I'd like to think that shifting is a distant 2nd on my priorities.
I guess I'm talking about power lost during transfer, but from a feeling point of view, I'm talking specifically about ease of pedaling. You know what I mean. A chain that gives the impression that you could pedal on at X cadence forever without a break.
Is this dictated just by the weight, or does shape and materials contribute as well?
The ease of peadling or the "effiency" you feel is all about the "ratio (sprocket combination), load (weight and the grade if a hill you may be riding on), current road speed, and lastley your physical energy at that particular moment.
I'd like to think that shifting is a distant 2nd on my priorities.
I guess I'm talking about power lost during transfer, but from a feeling point of view, I'm talking specifically about ease of pedaling. You know what I mean. A chain that gives the impression that you could pedal on at X cadence forever without a break.
Is this dictated just by the weight, or does shape and materials contribute as well?
The ease of peadling or the "effiency" you feel is all about the "ratio (sprocket combination), load (weight and the grade if a hill you may be riding on), current road speed, and lastley your physical energy at that particular moment.
Nessism
02-11-07, 08:19 AM
Friction is the only loss that occurs in chains. Keep it clean and lubed and you are good to go.
MudPie
02-11-07, 08:42 AM
From the book "Bicycling Science" by Wilson, 3rd edition, 2004, MIT Press, pg 317:
"Despite the importance of drive chain to bicycles and especially to industrial equipment, published research on it has been spotty, Some of the best work is secreted in manufactureres' vaults or stored in the minds of retired engineers, because there is no present commercial value to aplying or disseminating it."
Futher, the book references a Ph D dissertation by Mathew Kidd (Department of Mechanical Engineering at Heriot-Watt University, Edinburgh, Scotland) as a complete compilation of the available literature on efficiency and on the effects of tooth form.
From "Design of Machine Elements" by Spotts, 6th edition, pg 321, relates horsepower capacity to the fatigue life of the link plates (for lower speeds) and to fatigue life of the roller bearing (for higher speeds). These formulas seem highly experimental. For example, the former relates horsepower to:
N (number of teeth in the smaller sprocket) raised to the 1.08 power,
n, (rpm of the smaller sprocket) raised to the 0.9 power
p (pitch) raised to the (3-.07p) power
I'm hoping others have more definitive information.
"Despite the importance of drive chain to bicycles and especially to industrial equipment, published research on it has been spotty, Some of the best work is secreted in manufactureres' vaults or stored in the minds of retired engineers, because there is no present commercial value to aplying or disseminating it."
Futher, the book references a Ph D dissertation by Mathew Kidd (Department of Mechanical Engineering at Heriot-Watt University, Edinburgh, Scotland) as a complete compilation of the available literature on efficiency and on the effects of tooth form.
From "Design of Machine Elements" by Spotts, 6th edition, pg 321, relates horsepower capacity to the fatigue life of the link plates (for lower speeds) and to fatigue life of the roller bearing (for higher speeds). These formulas seem highly experimental. For example, the former relates horsepower to:
N (number of teeth in the smaller sprocket) raised to the 1.08 power,
n, (rpm of the smaller sprocket) raised to the 0.9 power
p (pitch) raised to the (3-.07p) power
I'm hoping others have more definitive information.
Wheelchairman
02-11-07, 10:55 AM
From the book "Bicycling Science" by Wilson, 3rd edition, 2004, MIT Press, pg 317:
"Despite the importance of drive chain to bicycles and especially to industrial equipment, published research on it has been spotty, Some of the best work is secreted in manufactureres' vaults or stored in the minds of retired engineers, because there is no present commercial value to aplying or disseminating it."
Futher, the book references a Ph D dissertation by Mathew Kidd (Department of Mechanical Engineering at Heriot-Watt University, Edinburgh, Scotland) as a complete compilation of the available literature on efficiency and on the effects of tooth form.
From "Design of Machine Elements" by Spotts, 6th edition, pg 321, relates horsepower capacity to the fatigue life of the link plates (for lower speeds) and to fatigue life of the roller bearing (for higher speeds). These formulas seem highly experimental. For example, the former relates horsepower to:
N (number of teeth in the smaller sprocket) raised to the 1.08 power,
n, (rpm of the smaller sprocket) raised to the 0.9 power
p (pitch) raised to the (3-.07p) power
I'm hoping others have more definitive information.Nope, I dought they would. Might as well do my own research. Seems that's all the info I'm going to get. Thanx for the info, mudpie. It's a start!
I ride HPV's, and thus we use 3 lengths of chain. Chainweight is obviously tripled, so I thought it'd be nice to know wether the efficentcy we get through our chains can be performed with heavier chains- that may indicate that weight is only one of the factors if so! Thought I'd come here 1st before doing that.
"Despite the importance of drive chain to bicycles and especially to industrial equipment, published research on it has been spotty, Some of the best work is secreted in manufactureres' vaults or stored in the minds of retired engineers, because there is no present commercial value to aplying or disseminating it."
Futher, the book references a Ph D dissertation by Mathew Kidd (Department of Mechanical Engineering at Heriot-Watt University, Edinburgh, Scotland) as a complete compilation of the available literature on efficiency and on the effects of tooth form.
From "Design of Machine Elements" by Spotts, 6th edition, pg 321, relates horsepower capacity to the fatigue life of the link plates (for lower speeds) and to fatigue life of the roller bearing (for higher speeds). These formulas seem highly experimental. For example, the former relates horsepower to:
N (number of teeth in the smaller sprocket) raised to the 1.08 power,
n, (rpm of the smaller sprocket) raised to the 0.9 power
p (pitch) raised to the (3-.07p) power
I'm hoping others have more definitive information.Nope, I dought they would. Might as well do my own research. Seems that's all the info I'm going to get. Thanx for the info, mudpie. It's a start!
I ride HPV's, and thus we use 3 lengths of chain. Chainweight is obviously tripled, so I thought it'd be nice to know wether the efficentcy we get through our chains can be performed with heavier chains- that may indicate that weight is only one of the factors if so! Thought I'd come here 1st before doing that.
Sheldon Brown
02-11-07, 11:05 AM
Nope, I dought they would. Might as well do my own research. Seems that's all the info I'm going to get. Thanx for the info, mudpie. It's a start!
I ride HPV's, and thus we use 3 lengths of chain. Chainweight is obviously tripled, so I thought it'd be nice to know wether the efficentcy we get through our chains can be performed with heavier chains- that may indicate that weight is only one of the factors if so! Thought I'd come here 1st before doing that.
The main things that determine chain efficience are chainline, sprocket size and sprocket ratio.
Straight chainline is best, efficiency goes down considerably with crooked chainline.
Larger sprockets are very slightly more efficient than smaller ones.
Greatest efficiency occurs with 1:1 gearing, but this fact is not particularly useful for bicycle applications.
For recumbents, chainline isn't generally an issue, since the chain is so long. The thing that kills drivetrain efficiency in most recumbents is the use of an idler pulley in the taut (upper) run of the chain. If you're fussy about efficiency, this is an area to concentrate on.
Sheldon "Greenspeed" Brown
I ride HPV's, and thus we use 3 lengths of chain. Chainweight is obviously tripled, so I thought it'd be nice to know wether the efficentcy we get through our chains can be performed with heavier chains- that may indicate that weight is only one of the factors if so! Thought I'd come here 1st before doing that.
The main things that determine chain efficience are chainline, sprocket size and sprocket ratio.
Straight chainline is best, efficiency goes down considerably with crooked chainline.
Larger sprockets are very slightly more efficient than smaller ones.
Greatest efficiency occurs with 1:1 gearing, but this fact is not particularly useful for bicycle applications.
For recumbents, chainline isn't generally an issue, since the chain is so long. The thing that kills drivetrain efficiency in most recumbents is the use of an idler pulley in the taut (upper) run of the chain. If you're fussy about efficiency, this is an area to concentrate on.
Sheldon "Greenspeed" Brown