ice109
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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?
cyrusabdollahi said:It would probably be horribly bumpy. That air acts as a damper. You will also have a much larger MOI.
no sarcasm, i sincerely meant that i positively would not want a bigger MOI.cyrusabdollahi said: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?
wheels are on a roadbike, don't need tractionbrewnog said:Aside from comfort, wear and protection, there's the issue of traction too...
cyrusabdollahi said: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 can't 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.
cyrusabdollahi said: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 going to work.
cyrusabdollahi said:I answered your questions already. See: Cogs.
are you seriously saying i should replace my entire wheel with a 27cm cog? and build a road with teeth?cyrusabdollahi said:When you have a cog type system on your wheels and on the ground, almost all the energy gets transferred from the axil to moving forward. You don't 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 won't be able to take any turns that don't have a bank built into them.
berkeman said:Well, since I have absolutely no idea what you guys are talking about anymore, I went back and googled "bib mousse" +"bicycle tire", and got some hits. Here is the solid foam bib mousse insert info for Michelin MTB tires.
http://shopping.yahoo.com/s:Cycling:4168-Brand=Michelin:4492-Sales%20&%20Deals=All%20Sale%20Items
Does that help with the OP?
cyrusabdollahi said:Hmmm, that's 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.
cyrusabdollahi said: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.
cyrusabdollahi said:You can check out this http://hyperphysics.phy-astr.gsu.edu/hbase/frict3.html
cyrusabdollahi said:I don't understand what you mean by 'cause' friction. I am saying without deformation, I don't think you will be able to produce enough friction to move forwards.
Did you scroll down the link?
cyrusabdollahi said:I got to think about this for a bit, let it stew in my head overnight and let me look online to see if I find anything for an ideal perfectly rigid disk.![]()
SRode said:Some of these postulate are rediculous, but to answer your question a solid rubber tire would be better because it would weigh more and conserve more angular momentum. This would be ideal if you were on a level surface and were traveling a long distance (same principle as a flywheel). The downside is that it would require a lot more force to slow down, thus wearing your brakes more, and greater force to accelerate. If you were trying to apply this to a car, it would be practical in that it would increase MPG because less engine power was required once in motion, but the stress it would put on the horizonal components in turning would be immense. Also the logistics of shipping pieces of heavy solid rubber like that would not be feaseable.
SRode said:Some of these postulates are rediculous
cyrusabdollahi said:How do you figure?
SRode said:Also the logistics of shipping pieces of heavy solid rubber like that would not be feaseable.
SRode said:Things are engineered in a way for a reason,
You are under the impression that, if tires were solid, they would keep the same geometry. Structurally, I don't think the tire could support itself. It would have to be a much lower profile tire.SRode said:Look at the average sedan tire 205/60/15:
section width 205mm, section height (.6*205) 123mm
Tires are not perfectly cylindrical but you can estimate their volume:
15in = 381mm
(205mm)*pi*((381mm+123mm)^2 - 381mm^2) = .07m^3
A tire is primarily carbon black, synthetic rubber, and natural rubber.
natural rubber has a density of .94 g/cm^3 = 940 kg/m^3
synthetic rubber has a density ~1.2 g/cm^3 = 1200 kg/m^3
Carbon black is just a reinforcement, and becomes neglible when you are talking about filling the entire inner volume with rubber.
You solid rubber car tire (assuming your using the least dense material of natural rubber) now weighs 66kg or 145 lbs.
That is the exact same tire/rim combo I have seen in industry design mags. The rim becomes a compliant part as well as the tire.SRode said:Ah, well then that's a whole different ball game. If you mean somthing like this:
http://www.speedace.info/speedace_images/michelin_tweek_airless_tire.jpg
There was a reason they haven't started producing them yet tho, I think it was that they transfer too much vibrational energy making them noisy.
K.J.Healey said:Just to add my own comments:
1) ... I would assume that for a bike you really don't need THAT much friction to get moving/keep moving/change direction.
3) Weight should not be an issue.
years of terch wnet into the current kelvar belt radial tires we use today..ifin firestone and goodyear thought solid was better it would a happened.
Innomen said:.
Adding a second suspension that takes over the job that the air is doing, is simply adding needelss cost.
They look stupid, but tweels are the future.
but lining up a brand new system, literally reinventing the wheel is an unnecessary expense for a questionalble performance increase.