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Old 01-13-09, 11:47 AM   #1
EvilV
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Air Free Tyres - Could they be OK?

Do you think there will ever be good solid tyres? The inconvenience of a flat is huge for a commuter, or any cyclist really. I'd have thought that some enterprising materials scientist could come up with a solid bike tyre system that would be resilient, low rolling resistance and still have a degree of 'give' in it.

There are people marketing such tyres including a manufacturer not too far from where I live.

What do you think?

An American seller (edit - see warning in post #4)
http://www.airfreetires.com/shopping...aspx?pagenum=2


A UK manufacturer
http://www.greentyre.co.uk/tyres.html

Last edited by EvilV; 01-13-09 at 12:59 PM.
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Old 01-13-09, 12:21 PM   #2
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You read about peopel trying them out ewery now and then. Can not remember reading about anybody tryed them out for folders. I guess they need to be made better than the present ones for peopel to choose them? If you`we got more than one bike you could have one with such tyres.

Tonight I am going somewhere around 20.00 hrs (pich dark), only 2 km ride, -3C. I am not in the mood for fixing flats in the dark and comfort is not a big problem on such a short ride. Also I think if I knew I was riding to the train or bus early tomorrow morning, no time for flats I would maybe also choose such tyres.
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Old 01-13-09, 12:33 PM   #3
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Personally I think it's a big investment to commit to one tire pressure at the time of purchase. So if you're depending on the tire for suspension, pneumatics offer a better value because they are adjustable.

However, I think polyurethane would be great if you had a high quality adjustable suspension like a Moulton. With lower rolling resistance and less maintenance what's not to like?
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Old 01-13-09, 12:40 PM   #4
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Bottom line? Don't buy from airefreetires... they took my money, I never got my tires, and I reported it too the CC too late (because of AFt's assurances that 'my tires were due in any day') for the CC company to do anything about it.

Buy direct from teh manufacture if you want to try them out NuTeck
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Old 01-13-09, 12:49 PM   #5
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People have been trying to invent good air free tires since the pneumatic tire was invented - with zero success - except for certain limited uses - like vehicles that move on rails or slow moving heavy equipment. The thing is air distributes the impact pressure of the ground all throughout teh tire, whereas a solid tire sends the impact straight up.

How about tank treads, like this?

http://www.popsci.com/crescent-shape...-personal-tank

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Old 01-13-09, 12:54 PM   #6
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I agree with what you people are saying about the problems of flats. I'd certainly think about buying some for my Strida knock off. The tyres it is fitted with are kind of low pressure, though I'm riding them a lot harder than the sidewall says. I had a puncture from a piece of glass a couple of weeks back and I'd only done about sixty miles on the bike from new. I was thinking of looking into some marathons, but they're not sure to resist glass. I emailed the UK tyre maker linked to above and when I find an outlet, I'll see what they cost. Maybe the factory will sell direct. I also need to measure the bead width of the rim. These tyres are very fussy about that since you can't just blow them out to fit.

The manufacturers are claiming that the tyres are as light or lighter than regular ones, and ride well. I've seen comments that they are squishy, but you never know what make of tyre these comments refer to. These polyurethane mixes can be made to have different pressure characteristics too. I'd love to hear from someone who'd ridden the new types that are on sale.
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Old 01-13-09, 12:58 PM   #7
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Bottom line? Don't buy from airefreetires... they took my money, I never got my tires, and I reported it too the CC too late (because of AFt's assurances that 'my tires were due in any day') for the CC company to do anything about it.

Buy direct from teh manufacture if you want to try them out NuTeck
That's a bummer. Thanks for that link to the manufacturer. I edited my original post to reflect your inf about them being a reseller.
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Old 01-13-09, 01:27 PM   #8
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These polyurethane mixes can be made to have different pressure characteristics too.
Yeah, but as werewolf said those pressure characteristics are directional whereas air pressure is isotropic.

However, since they can be made harder than pneumatics they do seem to dovetail nicely with the Moulton design philosophy: Optimize the wheels for a glass smooth surface and design a dedicated suspension to translate that performance onto rougher surfaces.

Why compromise on ride quality and performance with the soft ones when you can get a win win situation by using the hardest ones available on a bike with dedicated suspension?
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Old 01-13-09, 01:33 PM   #9
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I saw a prototype of an air-less tire years ago... it makes good sense to me.

However, I do have one concern. If you can stretch an airless tire into a rim, what's stopping it from coming off (you can't take off a conventional tire once it's inflated). Obviously, these things have been tested extensively otherwise they wouldn't be released into the market by now... so I have to assume it's not an issue.

I hate flats, so I'll be keeping an eye out for user feedback on this thread...
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Old 01-13-09, 01:39 PM   #10
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Originally Posted by makeinu View Post
Yeah, but as werewolf said those pressure characteristics are directional whereas air pressure is isotropic.

However, since they can be made harder than pneumatics they do seem to dovetail nicely with the Moulton design philosophy: Optimize the wheels for a glass smooth surface and design a dedicated suspension to translate that performance onto rougher surfaces.

Why compromise on ride quality and performance with the soft ones when you can get a win win situation by using the hardest ones available on a bike with dedicated suspension?
Interesting point.

I'd also be concerned, intuitively, that non-pneumatic tires would be hard on the spokes, and might not grip the road as well, especially when cornering at relatively high speed. (BWDIK)
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Old 01-13-09, 01:48 PM   #11
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Try tires with thicker tread and use thorn resistant tubes. I just ordered some today for my R20.

I suppose airless tires could be a good idea for folders though, if used along with folding wheels...
http://www.youtube.com/watch?v=nlRt3YOl00c
http://www.duncfitz.co.uk/wheel.html
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Old 01-13-09, 01:50 PM   #12
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Quote:
Originally Posted by makeinu View Post
Yeah, but as werewolf said those pressure characteristics are directional whereas air pressure is isotropic.

However, since they can be made harder than pneumatics they do seem to dovetail nicely with the Moulton design philosophy: Optimize the wheels for a glass smooth surface and design a dedicated suspension to translate that performance onto rougher surfaces.

Why compromise on ride quality and performance with the soft ones when you can get a win win situation by using the hardest ones available on a bike with dedicated suspension?
Yes - that's the compromise of all our small wheeled non-suspension bikes, and Moulton sort of solved it. The manufacturers of these say they can make them in any kind of pressure profile from 10 psi to well over 100psi. I think it's all a matter of how much gas they have inside the mix when they spin the polyurethane fluid into the moulds.

I'm not sure exactly what effect the directional Vs isotropic reaction would have on the rolling tyre. I think we should bear in mind that when the makers say they simulate various psi, they mean it rides 'like' whatever psi they say. I'm guessing a bit there though.

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Interesting point.

I'd also be concerned, intuitively, that non-pneumatic tires would be hard on the spokes, and might not grip the road as well, especially when cornering at relatively high speed. (BWDIK)
Why do you think they would be hard on the spokes? I'm sort of supposing that an airless tyre rated at 55psi rides somewhat like a 55psi pneumatic with similar reaction to road imperfections and load.

I'd quite like to try one on the back of my Strida Knock off if they are under about 20. I really hate having to dismount and walk with a flat tyre.
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Old 01-13-09, 01:53 PM   #13
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The Nu-teck FAQ answers parts of these questions. They say they've tested them thoroughly but don't describe but what device their tires manage to stay on the rim in the absence of air inflation. Nothing addresses spokes that I see.
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Old 01-13-09, 02:04 PM   #14
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Why do you think they would be hard on the spokes?
Because on a couple occasions I have broken a spoke or two by hitting a bad bump with my tires pumped up really hard. I figure the sharp impact sends a shockwave up the spoke, and when it reaches the flange it rips the head off the spoke. I really don't know whether there's any validity to this, though.
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Old 01-13-09, 02:17 PM   #15
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I saw a prototype of an air-less tire years ago... it makes good sense to me.

However, I do have one concern. If you can stretch an airless tire into a rim, what's stopping it from coming off (you can't take off a conventional tire once it's inflated). Obviously, these things have been tested extensively otherwise they wouldn't be released into the market by now... so I have to assume it's not an issue.

I hate flats, so I'll be keeping an eye out for user feedback on this thread...
As I understand it, you need to use some special stretching tool to fit the tyres. It's supposed to be quick to fit them, but I think they stay on once fitted. Some of the FAQs mentioned in a post just above this cover their ability to stay on the rim.
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Old 01-13-09, 02:22 PM   #16
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Can not belive it is harder on the spokes than a 100psi pneumatic 20 x 1,3 tyre?
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Old 01-13-09, 03:14 PM   #17
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I've considered these as well. The rear wheel on my Qile Duo VSTII folder is a b***** to remove, because there are so many things to loosen (kickstand, rack stays, fender stays, rear band brake cable, etc.). AirFreeTires is actually located right here in my city (Orlando).

While I don't have personal experience with them, years ago, I used to participate in a recumbent bicycle forum. There was a member of that forum who owned a high performance recumbent (Goldrush Replica), and he bought a set for his bike. He liked them very much! In fact, he started a thread on the AirFree tires that stayed in the first page of the forum for several weeks, resurfacing every now and then whenever some one had some comments.

But this bike owner reported that the tires rolled just as efficiently as the high pressure pneumatic tires he had replaced, and was most gleeful that any worries about having flats were now far behind him.

So I guess YMMV applies here.

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Do you think there will ever be good solid tyres? The inconvenience of a flat is huge for a commuter, or any cyclist really. I'd have thought that some enterprising materials scientist could come up with a solid bike tyre system that would be resilient, low rolling resistance and still have a degree of 'give' in it.

There are people marketing such tyres including a manufacturer not too far from where I live.

What do you think?

An American seller (edit - see warning in post #4)
http://www.airfreetires.com/shopping...aspx?pagenum=2


A UK manufacturer
http://www.greentyre.co.uk/tyres.html
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Old 01-13-09, 03:21 PM   #18
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That's a bummer. Thanks for that link to the manufacturer. I edited my original post to reflect your inf about them being a reseller.
Regardless of my bad experience with the reseller. I still plan on trying some NuTecks on a "beater bike" (SS or Fixed Gear that will be pretty much guaranteed to get me to work) at some point. I have ~ 5 mile commute so as long as their no too rough, the potential reduced efficiencies will (I suspect) pay for themselves in reliability. Actually, I've considered making my own "spiker" tires out of some... but those are projects for later...
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Old 01-13-09, 04:24 PM   #19
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Somewhere I saw a discussion of airfree tyres, and the conclusion was that a particular brand was not bad at all. They have come a long way.
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Old 01-13-09, 05:12 PM   #20
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Somewhere I saw a discussion of airfree tyres, and the conclusion was that a particular brand was not bad at all. They have come a long way.
For sure on the Dahon forum a few years back.. "pumpkinhead" wrote some on the airfree and liked them a lot.. here's one THREAD
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Old 01-13-09, 05:55 PM   #21
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Yes, absolutely there have been useful air-free tires for generations. You just need the right application. I have pedalled air-free tires on two continents. Cast aluminum in Ouray, Colorado and cast iron in South Africa. Four-wheeled bikes used in underground mines. Miners and mechanics used them to get around so they would not have to tie up an engine. In Colorado we used light aluminum wheels as we had to be able to lift the bike off of the tracks by our selves to get out of the way of ore trains. In SA I always had a work team with me and they lifted the 6 man iron wheeled bike off of the rails for me.
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Old 01-14-09, 04:14 AM   #22
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For sure on the Dahon forum a few years back.. "pumpkinhead" wrote some on the airfree and liked them a lot.. here's one THREAD
Useful to read someone's direct experience. Thanks for that.

I just phoned the UK manufacturer GreenTyre and they sell direct to the public, so I am going to measure my internal rim size on the strida knock off and if it is between 22-25mm, I will be sending for some of their 47-305 tyres. They are 13.99 which is cheaper than a Marathon here, but they do make a 10.99 consignment charge which bumps up the price a bunch. On the other hand they are only 32 miles away from here so I might just drive there if they will deal over the counter.

Since I started this thread, I suppose it is beholden on me to test them and report back. This all depends on my rims having suitable internal dimensions.....

Last edited by EvilV; 01-14-09 at 04:34 AM.
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Old 01-14-09, 04:29 AM   #23
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^ So, are you still going to give them a go?
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Old 01-14-09, 04:40 AM   #24
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^ So, are you still going to give them a go?
I think we crossed posts there Poko, I was editing mine and saying I was going to buy some when you posted that. As long as they will fit my internal rim size. That is a crucial element with these, because unlike pneumatics of course, they can't adapt to a smaller or larger rim size and it's the internal rim that holds them on. The web site gives the required internal measurement.

If you look at the diagram above the rim size figure, you can see why it is important for a solid tyre.

http://www.greentyre.co.uk/tornado.html
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Old 01-14-09, 06:22 AM   #25
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I was at one time, a Measurer of Road Running Courses, and for this used a bike with a solid front tyre.
A mechanical counter reads the distance travelled by the calibrated front wheel and it is vital that the circumference of the wheel remains constant throughout both calibration and measurement. A loss of pressure would invalidate the result.
The choice of tyres was limited, the ride fairly harsh, and I always went back to a pneumatic tyred wheel for normal cycling.
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