Momentum of rear derailleur wheels?
I have new derailleur and I am somewhat surprised that when I try to spin it with hand (no chain is mounted yet) it basically has no momentum, it almost immediately stops. Almost any other spinning part of the bicycle has much more momentum and spins for a while.
Granted, the wheels in derailleur are the lightest ones, but shouldn't they at least make a one full turn?
The screws are not too tightened because out of curiosity I loosened them already. No change.
derailleur-rear
asked 7 hours ago
greenoldmangreenoldman
6311719
add a comment |
I have new derailleur and I am somewhat surprised that when I try to spin it with hand (no chain is mounted yet) it basically has no momentum, it almost immediately stops. Almost any other spinning part of the bicycle has much more momentum and spins for a while.
Granted, the wheels in derailleur are the lightest ones, but shouldn't they at least make a one full turn?
The screws are not too tightened because out of curiosity I loosened them already. No change.
derailleur-rear
asked 7 hours ago
greenoldmangreenoldman
6311719
1
The cage bolts tighten onto the inner jockey wheel bearing, which is slightly wider than the wheel itself, so you cannot bind the wheel up by over-tightening the bolts.
– Argenti Apparatus
6 hours ago
This is fairly normal. I don't try spinning them too often, but on a well-oiled wheel if you can get one free turn out of them that's pretty good. The oil in the bearings creates a substantial drag, when compared to the minuscule momentum of the wheel.
– Daniel R Hicks
5 hours ago
add a comment |
I have new derailleur and I am somewhat surprised that when I try to spin it with hand (no chain is mounted yet) it basically has no momentum, it almost immediately stops. Almost any other spinning part of the bicycle has much more momentum and spins for a while.
Granted, the wheels in derailleur are the lightest ones, but shouldn't they at least make a one full turn?
The screws are not too tightened because out of curiosity I loosened them already. No change.
derailleur-rear
asked 7 hours ago
greenoldmangreenoldman
6311719
I have new derailleur and I am somewhat surprised that when I try to spin it with hand (no chain is mounted yet) it basically has no momentum, it almost immediately stops. Almost any other spinning part of the bicycle has much more momentum and spins for a while.
Granted, the wheels in derailleur are the lightest ones, but shouldn't they at least make a one full turn?
The screws are not too tightened because out of curiosity I loosened them already. No change.
derailleur-rear
derailleur-rear
asked 7 hours ago
greenoldmangreenoldman
6311719
asked 7 hours ago
greenoldmangreenoldman
6311719
edited 7 hours ago
greenoldman
asked 7 hours ago
greenoldmangreenoldman
6311719
asked 7 hours ago
greenoldmangreenoldman
6311719
asked 7 hours ago
greenoldmangreenoldman
6311719
6311719
1
The cage bolts tighten onto the inner jockey wheel bearing, which is slightly wider than the wheel itself, so you cannot bind the wheel up by over-tightening the bolts.
– Argenti Apparatus
6 hours ago
This is fairly normal. I don't try spinning them too often, but on a well-oiled wheel if you can get one free turn out of them that's pretty good. The oil in the bearings creates a substantial drag, when compared to the minuscule momentum of the wheel.
– Daniel R Hicks
5 hours ago
add a comment |
1
The cage bolts tighten onto the inner jockey wheel bearing, which is slightly wider than the wheel itself, so you cannot bind the wheel up by over-tightening the bolts.
– Argenti Apparatus
6 hours ago
This is fairly normal. I don't try spinning them too often, but on a well-oiled wheel if you can get one free turn out of them that's pretty good. The oil in the bearings creates a substantial drag, when compared to the minuscule momentum of the wheel.
– Daniel R Hicks
5 hours ago
1
1
The cage bolts tighten onto the inner jockey wheel bearing, which is slightly wider than the wheel itself, so you cannot bind the wheel up by over-tightening the bolts.
– Argenti Apparatus
6 hours ago
The cage bolts tighten onto the inner jockey wheel bearing, which is slightly wider than the wheel itself, so you cannot bind the wheel up by over-tightening the bolts.
– Argenti Apparatus
6 hours ago
This is fairly normal. I don't try spinning them too often, but on a well-oiled wheel if you can get one free turn out of them that's pretty good. The oil in the bearings creates a substantial drag, when compared to the minuscule momentum of the wheel.
– Daniel R Hicks
5 hours ago
This is fairly normal. I don't try spinning them too often, but on a well-oiled wheel if you can get one free turn out of them that's pretty good. The oil in the bearings creates a substantial drag, when compared to the minuscule momentum of the wheel.
– Daniel R Hicks
5 hours ago
add a comment |
2 Answers
2
active
oldest
votes
The derailleur wheels are small and light weight, so have very small moment of angular inertia. The bearings they run on need to withstand a significant force due to the action of the chain, not just the weight of the wheel. So the bearings are fairly robust and lubricated. As a result there is a little "greasy sliding resistance friction" (for want of a better word) in the bearing. The resistance is small and its effect on riding resistance virtually imperceptible, but as the wheel's angular momentum is also very small, it spins down rapidly if spun by hand.
If the wheel was engineered like a fidgit spinner then it would spin for ages, but its bearings would fail within minutes.
answered 7 hours ago
PenguinoPenguino
50239
Thank you very much, I already started worrying that I have to replace them or something :-).
– greenoldman
6 hours ago
Re: If the wheel was engineered like a fidgit [sic] spinner then it would spin for ages, but its bearings would fail within minutes.' - CeramicSpeed would probably disagree. It probably is possible to make small low friction bearings that are robust, they would just be very expensive.
– Argenti Apparatus
6 hours ago
3
To add a slight clarification to the answer: it's not that the jockey wheels have too much friction, rather they have too little mass to continue spinning.
– Argenti Apparatus
6 hours ago
Many jockey wheels just run on bushings. These will nearly never spin freely like a fidget spinner. OTOH, they work flawlessly for years and years. Bearings can gum up more quickly (even sealed). I've ordered cheap Chinese jockey wheels that came with "ceramic" bearings running in what appear to be nylon races. These spin freely like crazy, but I doubt they'll last long. I use them for low-stress idlers, and they do fine for that.
– WPNoviceCoder
36 mins ago
add a comment |
There are two types of mounts for jockey wheels - higher end ones come with bearings, and lower end ones come equipped with some "shells" that have no bearings.
The bearings roll much smoother, but add more moving parts to the system. Plus they cost a lot more for relatively small gains.
You do need to remember that the jockey wheels are under relatively low tension because they're on the part of the chain that is looser. The top jockey wheel also has to guide the chain onto the cassette, but the lower one only has to turn and maintain some tension on the chain.
So as long as they move freely and don't bind, a jockey wheel will function fine.
answered 3 hours ago
Criggie♦Criggie
42.8k570144
add a comment |
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2 Answers
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active
oldest
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2 Answers
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active
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The derailleur wheels are small and light weight, so have very small moment of angular inertia. The bearings they run on need to withstand a significant force due to the action of the chain, not just the weight of the wheel. So the bearings are fairly robust and lubricated. As a result there is a little "greasy sliding resistance friction" (for want of a better word) in the bearing. The resistance is small and its effect on riding resistance virtually imperceptible, but as the wheel's angular momentum is also very small, it spins down rapidly if spun by hand.
If the wheel was engineered like a fidgit spinner then it would spin for ages, but its bearings would fail within minutes.
answered 7 hours ago
PenguinoPenguino
50239
Thank you very much, I already started worrying that I have to replace them or something :-).
– greenoldman
6 hours ago
Re: If the wheel was engineered like a fidgit [sic] spinner then it would spin for ages, but its bearings would fail within minutes.' - CeramicSpeed would probably disagree. It probably is possible to make small low friction bearings that are robust, they would just be very expensive.
– Argenti Apparatus
6 hours ago
3
To add a slight clarification to the answer: it's not that the jockey wheels have too much friction, rather they have too little mass to continue spinning.
– Argenti Apparatus
6 hours ago
Many jockey wheels just run on bushings. These will nearly never spin freely like a fidget spinner. OTOH, they work flawlessly for years and years. Bearings can gum up more quickly (even sealed). I've ordered cheap Chinese jockey wheels that came with "ceramic" bearings running in what appear to be nylon races. These spin freely like crazy, but I doubt they'll last long. I use them for low-stress idlers, and they do fine for that.
– WPNoviceCoder
36 mins ago
add a comment |
The derailleur wheels are small and light weight, so have very small moment of angular inertia. The bearings they run on need to withstand a significant force due to the action of the chain, not just the weight of the wheel. So the bearings are fairly robust and lubricated. As a result there is a little "greasy sliding resistance friction" (for want of a better word) in the bearing. The resistance is small and its effect on riding resistance virtually imperceptible, but as the wheel's angular momentum is also very small, it spins down rapidly if spun by hand.
If the wheel was engineered like a fidgit spinner then it would spin for ages, but its bearings would fail within minutes.
answered 7 hours ago
PenguinoPenguino
50239
Thank you very much, I already started worrying that I have to replace them or something :-).
– greenoldman
6 hours ago
Re: If the wheel was engineered like a fidgit [sic] spinner then it would spin for ages, but its bearings would fail within minutes.' - CeramicSpeed would probably disagree. It probably is possible to make small low friction bearings that are robust, they would just be very expensive.
– Argenti Apparatus
6 hours ago
3
To add a slight clarification to the answer: it's not that the jockey wheels have too much friction, rather they have too little mass to continue spinning.
– Argenti Apparatus
6 hours ago
Many jockey wheels just run on bushings. These will nearly never spin freely like a fidget spinner. OTOH, they work flawlessly for years and years. Bearings can gum up more quickly (even sealed). I've ordered cheap Chinese jockey wheels that came with "ceramic" bearings running in what appear to be nylon races. These spin freely like crazy, but I doubt they'll last long. I use them for low-stress idlers, and they do fine for that.
– WPNoviceCoder
36 mins ago
add a comment |
The derailleur wheels are small and light weight, so have very small moment of angular inertia. The bearings they run on need to withstand a significant force due to the action of the chain, not just the weight of the wheel. So the bearings are fairly robust and lubricated. As a result there is a little "greasy sliding resistance friction" (for want of a better word) in the bearing. The resistance is small and its effect on riding resistance virtually imperceptible, but as the wheel's angular momentum is also very small, it spins down rapidly if spun by hand.
If the wheel was engineered like a fidgit spinner then it would spin for ages, but its bearings would fail within minutes.
answered 7 hours ago
PenguinoPenguino
50239
The derailleur wheels are small and light weight, so have very small moment of angular inertia. The bearings they run on need to withstand a significant force due to the action of the chain, not just the weight of the wheel. So the bearings are fairly robust and lubricated. As a result there is a little "greasy sliding resistance friction" (for want of a better word) in the bearing. The resistance is small and its effect on riding resistance virtually imperceptible, but as the wheel's angular momentum is also very small, it spins down rapidly if spun by hand.
If the wheel was engineered like a fidgit spinner then it would spin for ages, but its bearings would fail within minutes.
answered 7 hours ago
PenguinoPenguino
50239
answered 7 hours ago
PenguinoPenguino
50239
answered 7 hours ago
PenguinoPenguino
50239
answered 7 hours ago
PenguinoPenguino
50239
50239
Thank you very much, I already started worrying that I have to replace them or something :-).
– greenoldman
6 hours ago
Re: If the wheel was engineered like a fidgit [sic] spinner then it would spin for ages, but its bearings would fail within minutes.' - CeramicSpeed would probably disagree. It probably is possible to make small low friction bearings that are robust, they would just be very expensive.
– Argenti Apparatus
6 hours ago
3
To add a slight clarification to the answer: it's not that the jockey wheels have too much friction, rather they have too little mass to continue spinning.
– Argenti Apparatus
6 hours ago
Many jockey wheels just run on bushings. These will nearly never spin freely like a fidget spinner. OTOH, they work flawlessly for years and years. Bearings can gum up more quickly (even sealed). I've ordered cheap Chinese jockey wheels that came with "ceramic" bearings running in what appear to be nylon races. These spin freely like crazy, but I doubt they'll last long. I use them for low-stress idlers, and they do fine for that.
– WPNoviceCoder
36 mins ago
add a comment |
Thank you very much, I already started worrying that I have to replace them or something :-).
– greenoldman
6 hours ago
Re: If the wheel was engineered like a fidgit [sic] spinner then it would spin for ages, but its bearings would fail within minutes.' - CeramicSpeed would probably disagree. It probably is possible to make small low friction bearings that are robust, they would just be very expensive.
– Argenti Apparatus
6 hours ago
3
To add a slight clarification to the answer: it's not that the jockey wheels have too much friction, rather they have too little mass to continue spinning.
– Argenti Apparatus
6 hours ago
Many jockey wheels just run on bushings. These will nearly never spin freely like a fidget spinner. OTOH, they work flawlessly for years and years. Bearings can gum up more quickly (even sealed). I've ordered cheap Chinese jockey wheels that came with "ceramic" bearings running in what appear to be nylon races. These spin freely like crazy, but I doubt they'll last long. I use them for low-stress idlers, and they do fine for that.
– WPNoviceCoder
36 mins ago
Thank you very much, I already started worrying that I have to replace them or something :-).
– greenoldman
6 hours ago
Thank you very much, I already started worrying that I have to replace them or something :-).
– greenoldman
6 hours ago
Re: If the wheel was engineered like a fidgit [sic] spinner then it would spin for ages, but its bearings would fail within minutes.' - CeramicSpeed would probably disagree. It probably is possible to make small low friction bearings that are robust, they would just be very expensive.
– Argenti Apparatus
6 hours ago
Re: If the wheel was engineered like a fidgit [sic] spinner then it would spin for ages, but its bearings would fail within minutes.' - CeramicSpeed would probably disagree. It probably is possible to make small low friction bearings that are robust, they would just be very expensive.
– Argenti Apparatus
6 hours ago
3
3
To add a slight clarification to the answer: it's not that the jockey wheels have too much friction, rather they have too little mass to continue spinning.
– Argenti Apparatus
6 hours ago
To add a slight clarification to the answer: it's not that the jockey wheels have too much friction, rather they have too little mass to continue spinning.
– Argenti Apparatus
6 hours ago
Many jockey wheels just run on bushings. These will nearly never spin freely like a fidget spinner. OTOH, they work flawlessly for years and years. Bearings can gum up more quickly (even sealed). I've ordered cheap Chinese jockey wheels that came with "ceramic" bearings running in what appear to be nylon races. These spin freely like crazy, but I doubt they'll last long. I use them for low-stress idlers, and they do fine for that.
– WPNoviceCoder
36 mins ago
Many jockey wheels just run on bushings. These will nearly never spin freely like a fidget spinner. OTOH, they work flawlessly for years and years. Bearings can gum up more quickly (even sealed). I've ordered cheap Chinese jockey wheels that came with "ceramic" bearings running in what appear to be nylon races. These spin freely like crazy, but I doubt they'll last long. I use them for low-stress idlers, and they do fine for that.
– WPNoviceCoder
36 mins ago
add a comment |
There are two types of mounts for jockey wheels - higher end ones come with bearings, and lower end ones come equipped with some "shells" that have no bearings.
The bearings roll much smoother, but add more moving parts to the system. Plus they cost a lot more for relatively small gains.
You do need to remember that the jockey wheels are under relatively low tension because they're on the part of the chain that is looser. The top jockey wheel also has to guide the chain onto the cassette, but the lower one only has to turn and maintain some tension on the chain.
So as long as they move freely and don't bind, a jockey wheel will function fine.
answered 3 hours ago
Criggie♦Criggie
42.8k570144
add a comment |
There are two types of mounts for jockey wheels - higher end ones come with bearings, and lower end ones come equipped with some "shells" that have no bearings.
The bearings roll much smoother, but add more moving parts to the system. Plus they cost a lot more for relatively small gains.
You do need to remember that the jockey wheels are under relatively low tension because they're on the part of the chain that is looser. The top jockey wheel also has to guide the chain onto the cassette, but the lower one only has to turn and maintain some tension on the chain.
So as long as they move freely and don't bind, a jockey wheel will function fine.
answered 3 hours ago
Criggie♦Criggie
42.8k570144
add a comment |
There are two types of mounts for jockey wheels - higher end ones come with bearings, and lower end ones come equipped with some "shells" that have no bearings.
The bearings roll much smoother, but add more moving parts to the system. Plus they cost a lot more for relatively small gains.
You do need to remember that the jockey wheels are under relatively low tension because they're on the part of the chain that is looser. The top jockey wheel also has to guide the chain onto the cassette, but the lower one only has to turn and maintain some tension on the chain.
So as long as they move freely and don't bind, a jockey wheel will function fine.
answered 3 hours ago
Criggie♦Criggie
42.8k570144
There are two types of mounts for jockey wheels - higher end ones come with bearings, and lower end ones come equipped with some "shells" that have no bearings.
The bearings roll much smoother, but add more moving parts to the system. Plus they cost a lot more for relatively small gains.
You do need to remember that the jockey wheels are under relatively low tension because they're on the part of the chain that is looser. The top jockey wheel also has to guide the chain onto the cassette, but the lower one only has to turn and maintain some tension on the chain.
So as long as they move freely and don't bind, a jockey wheel will function fine.
answered 3 hours ago
Criggie♦Criggie
42.8k570144
answered 3 hours ago
Criggie♦Criggie
42.8k570144
answered 3 hours ago
Criggie♦Criggie
42.8k570144
answered 3 hours ago
Criggie♦Criggie
42.8k570144
42.8k570144
add a comment |
add a comment |
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The cage bolts tighten onto the inner jockey wheel bearing, which is slightly wider than the wheel itself, so you cannot bind the wheel up by over-tightening the bolts.
– Argenti Apparatus
6 hours ago
This is fairly normal. I don't try spinning them too often, but on a well-oiled wheel if you can get one free turn out of them that's pretty good. The oil in the bearings creates a substantial drag, when compared to the minuscule momentum of the wheel.
– Daniel R Hicks
5 hours ago