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Solid Tires/Wheels?

  1. Jul 18, 2007 #1
    other a bumpy ride and maybe expedient suspension/drivetrain wear, are there any reasons why you would not want solid ( solid rubber, tubeless) tires on a bicycle?
     
  2. jcsd
  3. Jul 18, 2007 #2
    It would probably be horribly bumpy. That air acts as a damper. You will also have a much larger MOI.
     
  4. Jul 18, 2007 #3
    damn that is absolutely true, and i positively don't want that. i just feel like the compression saps so much energy from me because of inelastic collisions with ... the ground.
     
  5. Jul 18, 2007 #4
    Ride my Carbon fiber bike, and ride my steel frame bike, and you will see the difference in the damping capacity instantly. You do notice the road vibrations that get transmitted through the bike. I would suspect a solid tire would transfer more energy, being one solid piece, than would a tire filled with air that can deform more readily.

    Ps, why the sarcasm?
     
  6. Jul 18, 2007 #5

    berkeman

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    One option for dirtbikes is to run the "bib mousse" foam insert, instead of an inflated innertube:

    http://www.motorace.com/miva/merchant.mv?Screen=CTGY&Store_Code=M&Category_Code=MTBM

    They are a little heavier, but are commonly used for riding and racing in the rocky desert, like on the Baja races. I don't know if they make versions for bicycles.

    BTW, another disadvantage of a solid tire would be the added weight, and the big addition to the wheels' moment of inertia (harder to accelerate).
     
  7. Jul 18, 2007 #6

    brewnog

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    Aside from comfort, wear and protection, there's the issue of traction too...
     
  8. Jul 18, 2007 #7
    no sarcasm, i sincerely meant that i positively would not want a bigger MOI.

    i don't think you understand what i'm saying, just like an under inflated tire steals energy versus a properly inflated tire i was thinking an inflated tire versus a solid tire steals energy.

    wheels are on a roadbike, don't need traction
     
    Last edited: Jul 18, 2007
  9. Jul 18, 2007 #8
    Well, I'm sure it probably does. In an ideal situation you want a solid tire running along a track with cogs on it. Any deformation will result in energy losses, but you made a big assumption when you said comfort aside. You cant put comfort aside on a vehicle with people in it. Even without people, that vibration will tear things appart and cost money. Everything in engineering is a tradeoff.

    I like having traction between my road bike and the ground. There's no way you're going to turn without traction. Roads are not banked specifically to road bikes.
     
    Last edited: Jul 18, 2007
  10. Jul 18, 2007 #9
    my OP implied i have already considered that the vibration will damage things, that is why i said bumpiness aside; because i already knew that.

    i am assuming that the rubber itself will deform to contour the road surface. so therefore i don't need further deformation from the shape of the tire for grip.

    a tangential question. how come car tires don't need tube but bike tires do? i do know of tubeless bike tires but you need to glue those to the rim and obviously for cars you don't need to glue anything. so what is the difference?
     
  11. Jul 18, 2007 #10
    I know what your OP implied, but I am pointing out to you the magnitude of your implication in an engineering sense. You are taking the main reason for having non-rigid tires and ignoring it.

    How about I ask why airplanes have big wings but ignore the effects of air? Aint gonna work.
     
  12. Jul 18, 2007 #11
    duelly noted, do you have any answers to my questions instead of telling me what is unengineerable?

    besides you act like there aren't vehicles, with occupants and which were engineered :surprised, with solid tires for this exact reason.
     
  13. Jul 18, 2007 #12
    I answered your questions already. See: Cogs.
     
  14. Jul 18, 2007 #13
    :confused: what do single speeds have to do with anything? or maybe you really do mean cogs plural in which case::confused: what does a cluster/cassette have to do with anything?
     
  15. Jul 18, 2007 #14
    When you have a cog type system on your wheels and on the ground, almost all the energy gets transfered from the axil to moving forward. You dont have to worry about traction or slip. There is very little deformation, and loss of energy, between the gears. That would be the most ideal 'solid' tire.

    If you try to make a 'solid' tire without any gears on it, you wont be able to take any turns that dont have a bank built into them.
     
    Last edited: Jul 18, 2007
  16. Jul 18, 2007 #15

    berkeman

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  17. Jul 18, 2007 #16
    are you seriously saying i should replace my entire wheel with a 27cm cog? and build a road with teeth?

    i don't see why you wouldn't be able to make turn on a solid wheel. think rollerblade wheels.
    although that's interesting, its not for what im imagining. especially since its not rigid, although obviously more rigid than a tire with no air in it.
     
  18. Jul 18, 2007 #17
    Hmmm, thats a good point. Give me some time to think about that. The solid tire might have grip, but let me double check. I'm having issue seeing how a solid tire would be able to transfer energy to the road. All tires have some finite amount of deformation, and I think this deformation is critical in moving forwards.
     
  19. Jul 18, 2007 #18
    why would it be? all you need is for the ground to apply a force on you. if a wheel is rolling without slipping it is the friction force applying this force. you don't need deformation to have friction.
     
  20. Jul 18, 2007 #19
    But F=u*N at the macroscopic level. When you have a perfectly rigid disk, you will have an infinitely thin line of contact area between the disk and the ground, and possibly F != u*N anymore.
     
  21. Jul 18, 2007 #20
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