Airless bicycle tires

[Led_Blind]

Good thread.

I ride a mtn bike to work 3 days a week as well as a crap load of bush riding. My main issue were pinch flats and less often ther would be a thorn in the tyre wall\bed. The bike runs tubeless tyres and now both the frot and back have tubes.

To get around all the flats we removed the tyre, cut a strip of tough cotton type material to fit inside and painted it in there with a thin silicone mix. The tubes have been removed, tubless valves installed and over 6 months of riding without a single flat.

On the negatives, the tyres are now heavier and you notice that in the bush when bouncing about of loggs and rocks. The bike is harder to flick around, but meh, its better than flats and when the bike has an unladen weight of 14kg i am not too fussed.

 

[Dr Jekell]

I run a road bike with front suspension and large knobly tires for going to work, into town etc

When I inflate the tires I usualy slightly underinflate them (Max 65 PSI normaly inflated to 60 PSI) and havn't had a puncture in the 3 years of having the bike using it at least 10 - 20 times a week.

I have (unfortunatly) riden over a lot of broken glass and other pointy things that people like to leave lying around and have had no problems except when you get that sinking feeling when you hear glass going crack.

When you run tires at or above their stated max presure rating you are reducing the amount of space inside the tire that the tube can expand into when going over bumps, obsticals and the like. Also the tube itself will be stretched thinner (like a ballon) than i should be alowing sharp and pointy things to enter easier.

My theory is that if you run the tires 5 PSI/KPA/etc under the stated max then you are providing A) more space to expand into, alowing for a smoother ride, and B) putting a more flexible tire in contact with the ground and anything on it, plus a tube with more thickness in the walls.

These are just my thoughts and if any one has any corrections let me know.

 

[chesterqw]

Zeus got tired of making lightning bolts i guess?

 

[monkeyboy]

I find that kevlar belted tyres are no good if the rubber cuts too easily. All that happens is that a piece of glass will lodge itself into the rubber and eventually work its way through the kevlar belt.

You should try Specialized armadillo's before giving up on inflatable tyres.

http://www.specialized.com/bc/SBCEqProduct.jsp?spid=26586

They're supposed to have the best pucture resistance.

 

[Coop]

I had good experiences with Schwalbe Big Apple, but these are pretty fat. A few sizes skinnier the Continental SportContact comes to mind. I ran these on a daily basis for about 2 years without a single flat.

 

[jtr1962]

I've decided to wait a bit because Air Free Tires (airfreetires.com) is coming out with the new Open Road series in 2008 which uses the new HR (high resiliency) material. The test data linked to earlier showed some 110 psi equivalent HR tires with a Crr in the 0.0078 area. This was without optimization. In this letter the company president posted on some newsgroup he said: "By using this formula we have cut the rolling resistance in half and by utilizing some new shapes and tweaking the formula a bit, we feel we can get the tire down to .005 or thereabouts."

I have no idea how good the new series of tires will be, but even if they can't do better than 0.006 to 0.007 they will still be as good as many pneumatic tires.

A recent review of some of their current tires. Interestingly, in the winter the reviewer found no rolling resistance difference but in the summer he said the tires were about 2 mph slower. Some HPV coast-down data suggests that pneumatic tires roll worse in colder weather while the airless appear to roll better. I imagine then at some critical temperature there is no performance difference. I might not do too badly ordering one of their current series now but the Open Road series sounds like it's worth waiting for. I guess then I'll get new wheels and try the Panaracer Pasela Tourguards mentioned in post #16. By the time they wear out, the new line of airless tires will hopefully be available.

 

[geepondy]

Flat tires is one of the reasons my hybrid has become my number one street bike. Sure I'll drop a bit on the average speed but in the end get just as good of a workout and have gotten one flat in about ten years.

 

[jtr1962]

Flat tires is one of the reasons my hybrid has become my number one street bike. Sure I'll drop a bit on the average speed but in the end get just as good of a workout and have gotten one flat in about ten years.

How much speed would you estimate you lose? Lately most of my rides have averaged in the 15.5 to 17 mph area. However, that includes slowing/stopping for obstacles or traffic signals. Unfettered, I'd probably average around 21 to 23 mph. I'm not sure I would want to ride anything much slower. As it is I wish my bike were much faster. Besides the workout, I find the sensation of speed exhilarating. I'll usually push it to at least 35 mph at some point in the ride.

BTW, the more I'm reading about this the more I'm thinking of going airless right now. It seems all the solutions to flats such as Armadillos, wider, heavier tires, Tuffy rim strips, etc. increase rolling resistance a good deal anyway. And the airless tires can be customized for a higher psi, which should reduce rollling resistance somewhat. In the review I linked to two posts above the person use Daytona HPs with a 90 psi equivalent. I might try the Daytona TTs with a 120 psi equivalent, but with a higher custom psi. They have a special at $50 a pair plus $5 to customize the psi. If they turn out to be no good for every day riding, I'll just put them on my second (emergency) bike. However, based on the reviews I've read the only drawback seems to be a slightly harsher ride, and higher rolling resistance. I'm hoping tires customized to perhaps 175 psi can eliminate the latter. I can get a sprung seat to reduce the former. Not needing to worry about patches of glass, or blowouts if I'm going 50+ mph on a steep downhill, would go a long way towards making my cycling safer/more fun.

 

[geepondy]

I would say probably a couple. My average speeds are not as fast as yours. When I'm in good shape, on the road bike I might average about 17 mph at least on the shorter runs but it's largely in unfettered territory. On the hybrid, I rarely hit 15 but generally it's fairly hilly terrain and I'm not sure the downhill speeds can make up for the uphill climbs. Also I run what I would consider "moderate" 700x35's on the hybrid meaning they have a fairly smooth center but tread on the outside. This is suitable for my needs as I sometimes hit dirt roads. There are skinnier, less tread tires available for the hybrids but then again when one goes that far, why don't they just ride a road bike instead. Hybrids are pretty customizable though. I've seen some that were almost road bikes and some that were almost mountain bikes.

It sounds like you're into the speed exhilaration so I don't think you'd like a hybrid but it might be fun to try. You'd be able to hop on sidewalks with ease and have a much stabler ride over potty roads and sand, etc.

If it wasn't 93 degrees, groan, I'd take the bike out for a ride today but just a little too hot as well as very humid to chance it. Maybe if I was still 25.

How much speed would you estimate you lose? Lately most of my rides have averaged in the 15.5 to 17 mph area. However, that includes slowing/stopping for obstacles or traffic signals. Unfettered, I'd probably average around 21 to 23 mph. I'm not sure I would want to ride anything much slower. As it is I wish my bike were much faster. Besides the workout, I find the sensation of speed exhilarating. I'll usually push it to at least 35 mph at some point in the ride.

 

[jtr1962]

It sounds like you're into the speed exhilaration so I don't think you'd like a hybrid but it might be fun to try. You'd be able to hop on sidewalks with ease and have a much stabler ride over potty roads and sand, etc.

If I find one to try out I'll give it a go just for the heck of it. I did try a friend's MTB a few times. After coming back from a ride dripping in sweat I actually asked him what was wrong with the bike. He said nothing. The tires felt like they were low on air to me, and in general the whole thing just felt dampened compared to my road bike. It was as if my pedaling effort just disappeared. I'd guess a hybrid would be somewhere between that and my road bike. I'll also note that my bike is in pretty bad shape. The rear wheel is wobbly, the tires are old, the drivetrain needs tuning, etc. I wouldn't be surprised if I could ride your hybrid as fast as my road bike at this point. Once I get the new wheels/tires/drivetrain it'll hopefully be a different story.

BTW, your speeds are still pretty respectable both for your age and riding a hybrid. The majority of riders I pass, even younger ones in their teens or twenties, are lucky to be going 15 mph.

If it wasn't 93 degrees, groan, I'd take the bike out for a ride today but just a little too hot as well as very humid to chance it. Maybe if I was still 25.

Same weather here so I just ride at 9 or 10 PM. I'll still be dripping in sweat after a 90 minute ride, but at least it's tolerable (barely). I can't wait for that nice, crisp fall weather to go on some nice 2 hour rides.

 

[will]

I ride an old Schwinn road bide for exercise around town. I will also ride a MTN bike on ocassion on the same route. The big difference is the tires between the two, The road bike will keep rolling after you stop pedaling. The MTN bike seems to just stop, or slow down very quickly with the knobby tires. I have increased the air pressure to 75 in the MTN bike, that helps. A few years back I picked up a set of "city" tires for the MTN bike. They are basically smooth tires with an inverted tread. That made a big difference by reducing the rolling resistance of the MTN bike.

The long and the short of it all - road bikes are fast on pavement, MTN bikes are good in the dirt. The hybrid bike tries to take a little of each.

 

[cave dave]

In short, they don't work. They typically fall short
in most (or all) of the following categories:
- weight (too high)
- rolling resistance (too high)
- retention (they fall off the rim or slip around the rim)
- ride (harsh)
- cornering (little grip, squirming tire)
- wet weather handling

It sounds like you riding is way to aggressive to use them.

I had good luck using the Mr. Tuffy tire liners, and I use to ride through a shipyard every day. It was covered with bits of metal and glass, etc

I inhabit a bike forum and the Schwalbe are highly rated. Heavy and not very supple but very puncture resistant.

 

[jtr1962]

In short, they don't work. They typically fall short
in most (or all) of the following categories:
- weight (too high)
- rolling resistance (too high)
- retention (they fall off the rim or slip around the rim)
- ride (harsh)
- cornering (little grip, squirming tire)
- wet weather handling

Going down that list, at least with the tires I'm looking at, the areas they may fall short in are rolling resistance, ride, cornering, and wet weather handling. Weight is comparable to clinchers according to the review, and lack of retention is only caused if the you get the wrong tire size. Poor cornering is really what will be the show stopper for me even if the tires measure up everywhere else. I'm not riding regularly on tires which might be dangerous. For $55 plus shipping I'll probably give them a try when I get my new rims. Worst case, if I don't like them I'll put them on my other bike, and get regular tires, perhaps with a slime strip. You may be right. My riding style may well be too aggressive for airless tires. No way of knowing though until I try them.

I had good luck using the Mr. Tuffy tire liners, and I use to ride through a shipyard every day. It was covered with bits of metal and glass, etc.

I've read mixed reviews on these. Some people like you love them. Others claim they actually ruin inner tubes, increase rolling resistance, or give a very harsh ride. In fact, I've read mixed reviews on just about every product to reduce flats. I'm starting to think the only thing is to try out one thing after another until finding something that works. Lots of alternatives in this thread if the airless tires turn out to be garbage.

 

[Wyeast]

I'm bumping this thread because I've starting riding a lot more lately, so I plan to give my bike a major overhaul within a month or so. First, I'll definitely be getting new wheels. I'm considering these. My main concern is that these only have 24 spokes compared to the 36 spokes I've used all my life. Is my concern warranted, or has wheel/spoke technology advanced to the point where a 24-spoke wheel can handle rough city riding? On the plus side, the 24 aero spokes instead of 36 round ones in front, plus the aero profile, should help. I plan to use my rear disc wheel cover in back as I'm doing now, so no real advantages there other than maybe lighter weight.

The need on spoke count depends greatly on your riding style, and the weight the bike is carrying. If you're sort of a regular joe who isn't carrying a lot of weight on the bike, you're probably ok with a quality lower-count wheel if it has deep strong rims, and preferably if you have good wheel builder at least go through and hand-tension the spokes.

If you're a heavier guy and/or you carry a lot of stuff on panniers then you could be in for some grief by riding over rough potholes too hard.

Good luck!

 

[jtr1962]

The need on spoke count depends greatly on your riding style, and the weight the bike is carrying. If you're sort of a regular joe who isn't carrying a lot of weight on the bike, you're probably ok with a quality lower-count wheel if it has deep strong rims, and preferably if you have good wheel builder at least go through and hand-tension the spokes.

If you're a heavier guy and/or you carry a lot of stuff on panniers then you could be in for some grief by riding over rough potholes too hard.

Right now I'm in the 200 pound area (trying to get down to 160-170) but never carry anything, not even an air pump or a water bottle. Hopefully I'll be OK. I don't see myself ever doing the sort of really long distance rides where I would need to carry heavy loads. Just not my cup of tea. I would however like go on somewhat further rides than I do now. The possibility of flats has actually prevented that since walking the bike 15 or 20 miles home wouldn't be very appealing, nor would I want to carry the tools to fix flats on the road. Another review of airless tires.

 

[CodeOfLight]

If you have skinny road tires, and you are riding at speed in bumpy roads, you might be getting snake bite punctures. This happens when the tire compresses all the way to the rim, and the sharp rim will pinch the tube so much that it will puncture the tube. It is called snake bite because that is what it looks like on the tube when you take it out. It will look like two puncture marks side by side. You can buy a special anti-snake bite rim that will eliminate this kind of puncture. The anti-snake bite rims have a flat area on the rim where this pinch would occur. This distributes the impact against the rim to about 10 times the area it would have been, preventing the puncture.

 

[soffiler]

...The possibility of flats has actually prevented that since walking the bike 15 or 20 miles home wouldn't be very appealing, nor would I want to carry the tools to fix flats on the road...

Why?

I am a serious cyclist, and I believe this is the first time I've ever heard anyone say this, ever. A kit to fix flats is small, lightweight, inexpensive, and easy to carry.

 

[jtr1962]

Why?

I am a serious cyclist, and I believe this is the first time I've ever heard anyone say this, ever. A kit to fix flats is small, lightweight, inexpensive, and easy to carry.

Since you asked...

The kit is small enough but the air pump isn't. Nor do I have the strength in my hands to pump up the tires using a hand pump (I have carpal tunnel syndrome). Also, 95% of my flats are in back. Every time I've removed the rear tire there's problems getting everything back right (i.e. it's a 30 minute ordeal requiring more tools than a patch kit), not to mention the greasy mess dealing with the chain. On a more practical note I do a lot of riding in weather which is too cold for rubber cement to set properly. It's more problems than it's worth trying to repair flats on the road. Given that this is NYC, if it's too far to walk I can find a bus or train. Like I said, I'm not really a long distance rider anyway. The most I might want to go is 15 or 20 miles from home, even with airless tires.

Interestingly, my brother was also excited at the possibility of decent airless tires. He said he totally gave up riding on account of flats. Unless you live in NYC you have no idea how bad the problem of flats is here. My rationale with fixing flats on the road is why bother since I might miss a piece of glass, and then flat again three blocks later. I can do a much more thorough job at home. Even doing that, I've gotten flats sometimes three times in the same day.

If you have skinny road tires, and you are riding at speed in bumpy roads, you might be getting snake bite punctures.

I got snake bite punctures exactly twice in my life, ironically two days in a row, about two weeks ago. It was totally my fault for not seeing the potholes. The main cause of flats has been glass in the rear tire.

Honestly, after reading two reviews so far of airless tires by serious cyclists, it seems they've improved a lot over what existed even ten years ago.

 

[WNG]

Perhaps you should try cyclo-cross tires....

http://www.nashbar.com/profile.cfm?...re&estoreid=961&pagename=Estore: Outlet Store

Also, if you are upgrading your drivetrain to 10spd, you may need a compatible crankset as well, since the chain will be narrower and may not work with a 7-8 spd spacing.
If you have a 9 spd setup, it should be OK.

I'm an old road rider, used to ride in Queens and Manhattan, then S.I. before giving it up due to rotten roads. It was poor conditions back then, I can imagine how bad it is now.
I managed to survive on 27x1" and 27x1 1/8" tires, and later 700x25. But punctures were a fact of life. Fixing flats become second nature and you develop a quick technique to it and keep messes to a minimum. Usually, one can patch a tube in under 15 min. It helps to have a minimum of tools, and a cleanly maintained bike.

As for hand-pumping tires, I still have my pair of Silca frame pumps, but I don't really rely on them anymore. I carry a CO2 cartridge filling unit with me.
It's small and sufficient enough to fill a tire to get you moving again. It'll support shrader and presta valves for road and mtb owners.

For cities, I now firmly believe a hybrid is best suited for everyday riding.
More rugged, and customizable to cope with the conditions. And if set up right, they aren't slow.
Even switching a mtb's knobbies for baldies make a hell of a difference rolling wise.

My idea of a city bike:
A hybrid/cyclo-cross frame with V-brakes for powerful braking, 700c rims w/ 32-hole spoking (I'm old school, 16 spoke isn't going to cope with 200 lbs of rider), rolling flat resistant rubber, a 48 tooth max chainwheel, and 11 tooth min sprocket for good cruising speed, and a flat handlebar for comfort and control. Also a set a SPD pedals and SPD shoes so you can still walk normally.

 

[jtr1962]

I'm bumping this thread because I ordered the airless tires and after 14 months (!) they finally came. These are what I ordered, customized with the maximum 175 psi option. While I consider the customer service totally unsatisfactory so far I'm pretty impressed with the tires. While I'll undoubtedly have further comments as I get more experience, here's my take after the first ~250 miles:

Ride quality: At first the ride seemed somewhat harsh. I literally felt every imperfection in the road. However, the tires started to feel smoother a few days later. Perhaps the material flexing broke in much as a new shoe takes time to break in before it's comfortable. Whatever the reason, at this point the tires aren't horribly worse than pneumatics as far as ride quality goes. On smooth roads they're great. On potholed roads they're rough but then so are 110 psi pneumatics. They certainly sound noisier over bumps so they may give the impression of riding much harder than they really do. I don't find significantly more shock transmitted through the handlebars than I did with pneumatics.

Traction: When I was putting together my bike I noticed that I could slide the front wheel on a vinyl tile floor. I attributed this to the mold release. Just as a precaution, I removed the excess material along the seam with a utility knife. This increased the traction. On the road traction is as good as any air tire, and should only get better as the tire picks up road grit. I feel perfectly safe on these tires, even riding in rush hour traffic.

Fit and ease of mounting: The tires went on fairly easily, and perfectly fit my rims. I highly doubt the tires will roll off no matter what I do.

Rolling resistance: Just as I noted regarding ride quality, I'd say these tires need to break in for a few hundred miles at least to realize their ultimate potential. After only about 50 miles rolling resistance decreased notably. Also note that these tires required the skewers to be tighter in order to keep the wheels from shifting over hard bumps. Prior to tightening the skewers the wheel moved enough to cause the brakes to slightly rub. I wonder how many others this happened to and they attributed the increased rolling resistance to the tire instead of the brake rubbing? Anyway, since the rims and drivetrain are new on this bike and need to be broken in, I can't say for sure how the rolling resistance compares to pneumatics. After about 120 miles the bike was about 1.5 mph slower but a good portion of this could easily be attributable to the wheel bearings still breaking in as well as the chain/ratchet mechanism/bottom bracket still being stiff compared to my other bike. Now after 250 miles the rolling resistance seems to be even less. I really do think the airless tires have a somewhat long break-in period before they develop their minimal rolling resistance. Maybe the extra psi option does help rolling resistance considerably also compared to the stock psi. As the tires wear into the optimum shape from riding I'm sure this will help the rolling resistance even more. One thing to note which I mentioned earlier was that pneumatics more or less double in rolling resistance going from 80°F down to 40°F while the airless tires either decrease or stay the same (honestly, it seems so far they stay the same although others have said they roll better at lower speeds. Regardless, at some temperature airless tires will be as good or better than pneumatics. Although such tests are inherently difficult, I've roughly estimated the Crr of my airless tires to be in the 0.008 area. This isn't that much worse than even the best pneumatics, and right around where many touring tires are. And it's better than most MTB tires or heavy, flat-resistant tires.

So here's the overal grading comparing to pneumatics:

Ride quality:

Airless: B+ (slightly harsh over smaller bumps but not overly so, no squishy feel like pneumatics)
Pneumatics: A- (pretty smooth overall but sometimes "squishy" when you rise in the saddle)

Traction:

Airless: A
Pneumatics: A

No significant differences here

Fit and ease of mounting:

Airless: B+ (kind of a pain to mount but fit perfectly, must choose tire size matched to your rim width)
Pneumatics: A- (more forgiving of rim width and usually easy to mount)

Rolling resistance:

Airless: B+ (somewhat to significantly more than pneumatics depending upon tire choice, high rebound material solves these problems but not available for all tire sizes)
Pneumatics: A- (can be as low as Crr 0.004 but rolling resistance increases at low temperatures and depends upon keeping the tire properly inflated)

Ease of use:

Airless: A+ (no maintenance whatsoever once tire is mounted)
Pneumatics: B (requires occasionally topping off for optimal performance)

Flat resistance:

Airless: A+ (by definition you can't get flats)
Pneumatics: C (note this is based on my own personal experience, while methods exist to lessen flats they ALL increase weight or rolling resistance, and you still need to keep the tire properly inflated).

Weight:

Airless: A- (while my tires aren't any heavier than comparable air tires some models are)
Pneumatics: A

Lifespan:

Airless: A (by most accounts the model tire I bought will last at least 8,000 miles, some with the new high-rebound material have lasted over 27,000 miles)
Pneumatics: B (most tires last 3000 miles or less unless they have a heavy, high-rolling resistance tread)

Rim Protection:

Airless: B+
Pneumatics: B+

Despite what others have said, after 250 miles my wheels are still perfectly true and undented. However, I'll grant that over a really severe pothole I will get rim damage but then again I'll also get it with pneumatics. Hence my grade of B+ for both.

Really, the only issues with airless tires at this point are higher rolling resistance for some models and in some cases a slightly harsher ride. They match or exceed pneumatics in every other area.

Other than the horrid customer service there are no show stoppers to using these tires. From what I read you'll get much better customer service ordering the tires directly from the manufacturer (nu-teck.com) rather than airfreetires.com but you will pay more. I can only hope by the time these tires are worn out that there will be an even greater selection of these tires, and that the 700c narrow tires will be available in the new high-rebound material. A high pressure high-rebound tire would have less rolling resistance than most air tires.