Momentum of rear derailleur wheels?












1















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.










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  • 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
    2 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
    1 hour ago
















1















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.










share|improve this question




















  • 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
    2 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
    1 hour ago














1












1








1








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.










share|improve this question
















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






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share|improve this question













share|improve this question




share|improve this question








edited 3 hours ago







greenoldman

















asked 4 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
    2 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
    1 hour ago














  • 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
    2 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
    1 hour 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
2 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
2 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
1 hour 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
1 hour ago










2 Answers
2






active

oldest

votes


















6














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.






share|improve this answer
























  • Thank you very much, I already started worrying that I have to replace them or something :-).

    – greenoldman
    3 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
    2 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
    2 hours ago





















0














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.






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    2 Answers
    2






    active

    oldest

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    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    6














    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.






    share|improve this answer
























    • Thank you very much, I already started worrying that I have to replace them or something :-).

      – greenoldman
      3 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
      2 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
      2 hours ago


















    6














    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.






    share|improve this answer
























    • Thank you very much, I already started worrying that I have to replace them or something :-).

      – greenoldman
      3 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
      2 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
      2 hours ago
















    6












    6








    6







    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.






    share|improve this answer













    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.







    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered 3 hours ago









    PenguinoPenguino

    50239




    50239













    • Thank you very much, I already started worrying that I have to replace them or something :-).

      – greenoldman
      3 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
      2 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
      2 hours ago





















    • Thank you very much, I already started worrying that I have to replace them or something :-).

      – greenoldman
      3 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
      2 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
      2 hours ago



















    Thank you very much, I already started worrying that I have to replace them or something :-).

    – greenoldman
    3 hours ago





    Thank you very much, I already started worrying that I have to replace them or something :-).

    – greenoldman
    3 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
    2 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
    2 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
    2 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
    2 hours ago













    0














    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.






    share|improve this answer




























      0














      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.






      share|improve this answer


























        0












        0








        0







        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.






        share|improve this answer













        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.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 13 mins ago









        CriggieCriggie

        42.8k570144




        42.8k570144






























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