Airless, solid Bike Tubes
This is a question and answer thread about solid (airless) bicycle tubes. The author,
David Barth, has used this type of tube for more than 15 years.
Below, he has answered some questions and responded to answers by others regarding solid tires and tubes
that have been asked by frustrated bicycle riders who condemn and loathe tubes
that contain air because they eventually go flat.
Question: Why do tires that have tubes filled with air go flat?
- David's answer: There are two major reasons.
- When ridden, bicycle tires sometimes pick up sharp objects which penetrate the tire
and the tube. The resulting hole in the tube allows air to escape. The rider is left without a
means of transportation, more or less stranded, and forced to find an alternate way home or to
a location where the tube can be repaired. Sharp objects on the riding surface can be numerous,
including nails, thorns, cactus, sharp rocks, glass, sharp metal, and basically, anything that is
hard and pointed.
- When not ridden for long periods of time, for example during winter months, tires
with air tubes usually go flat because tubes containing air are not perfectly sealed. There may be
leaks through the valve, even if it is capped, and there are microscopic leaks through the rubber
tube, itself. These leaks are most noticible after several months of inactivity.
During the riding season, a bicyclist will often
top off a tire when he or she notices that the tire is slightly flat. Adding air to a tire can be
done at a convenient location where there is an air pump or by
using a hand pump. In these cases, the bike can still be ridden, so there is no danger of being
stranded as when a tube is punctured.
Question: I've been looking at some product literature for puncture proof inner tubes. Has anyone
used this product, or something similar? What do you think?
Someone else's answer: Haven't used it; the idea is unappealing for a couple of reasons, and I'm sure
there are other drawbacks I haven't thought of.
- David's Answer: I have been riding on solid (airless) tubes for 15 years on a bike
with 26 by 1 3/8 inch tires and on a mountain bike with 26 by 2.10 inch tires. The tires are the
standard ones that used to have air tubes inside. The solid tubes were installed inside these tires.
Naturally, tires wear out, but no faster than they do with air tubes. The solid, airless tubes have
never given any problems. During this 15 year period,
the bikes always have been ready to be ridden.
Question: Is a solid tube difficult to install?
Someone else's answer: If the product is the right size for your tire, installation is no picnic. If
installation is easy, it's not the right size. Imagine trying to install the tire in between the
tube and rim with the tube inflated, if a tube existed that would permit such a procedure. That's
what you're doing if the thing is really designed to maintain the same level of effective inflation
tension on the tire bead as would be produced by conventional methods.
Part of the reason that the tension is needed there is to keep the tire from squirming out of the rim.
If you don't maintain that tension, what's likely to happen? If you do manage to get the solid tube
into the tire, then getting the tire on to the rim is going to be interesting.
Remember that with the regular tube deflated, what eases the
process of getting the tire onto the rim is the fact that the tire bead can drop into the spoke head
area in the rest of the circumference to allow a bit more room to get the last bit over the edge of
the rim. That's not likely to be possible with these.
- David's Answer: In the above comment, notice that the person responding says, "That's not likely to be
possible with these," referring to the difficulty of mounting a tire with a solid tube in it. This
person, who has no experience and yet is willing to showcase his ignorance, is not very
intelligent.
The truth is that solid tubes are different from air tubes. If you inflate an air tube to the pressure
required to ride the bike, it will be more than twice the diameter of the tube prior to being filled,
and of course, it would be nearly impossible to mount. As for a solid tube, it has a fixed size. To
install an airless tube, place it into the tire, and mount the tire as you normally would. I use a
couple of screwdrivers to work the tire onto the rim. It is no more difficult than when mounting a
deflated air tube in a tire. In any case, a person must be careful not to damage the tire with the
screwdrivers.
Question: How much does a solid, airless tube weigh?
Someone else's answer: Most solid tubes weigh only about a pound more than a normal thorn-proof inner
tube (depending upon the tube size). A normal bike lock and cable, a briefcase, or schoolbooks add far
more weight to two solid tubes.
- David's Answer: Two pounds is a pittance for 99 percent of the population. Extreme and professional
riders who want to reduce every extra pound of weight should consider using tires with air in the
tubes or losing a couple of pounds, themselves. Worring about two extra pounds of the bike and rider
is as illogical as buying a streamlined helmet like those used in the Tour de France. For 99 percent
of the biking population, streamlined helmets are a joke. They are simply a fashion statement, and
they won't gain the average rider (pro bikers call them "tourists") any measurable increase in
efficiency. Two extra pounds in the tubes won't affect the riding experience of anyone except those
guys who own $10,000 specially built bikes.
Question: Is a solid tube filled with a foam or gel sealant?
Someone else's answer: Solid tubes contain no foam or gel sealants.
Someone else's comment: Ahhh, the ambiguity of the English language. Many, if not most, will read
that as meaning "contain no foam, or gel sealants", implying that the design doesn't use a foam
interior. What it says, however, is that it contains no foam sealant or gel sealant. In other words,
it's a foam noodle with a non-foam resilient cover, but there's no sealant inside.
In its defense, I think it's an excellent product for use on wheelchairs, very small kid's bikes,
garden carts and the like, where speeds of travel will be low. In fact, I might even pick up a
couple to use on the garden cart I plan to build, while they are still in stock at Wal-Mart. But I
won't be using them on any of my bikes.
- David's Answer: Obviously, the above denigrating comment is from someone who is against
airless bicycle tires. Who would this be? Bicycle shops, of course! They have a vested interest
in selling and repairing flat tires, so they are against solid tires. Consider what the impact
on bike shops would have been if
every bicycle had been fitted with solid tubes 15 years ago, as mine were? The economic impact
on bike shops would be significant.
Of course, bike shops would deny that they receive sigificant
income from fixing flats and replacing tubes, but the truth is that flat tires bring people into
a shop, and these people often purchase other items such as lights, seats, reflectors, and many
other accessories. So, it is obvious that bicycle shops abhor solid tubes, and the respondent, above,
appears to have an axe to grind. The respondent can be generous to the crowd who use wheelchairs,
small kid's bikes, and garden carts because his bike shop doesn't make much money from them.
He likes to minimize the value of solid tubes by saying that Wal-Mart carries them, but that chain has never carried
solid tubes for adult bicycles. His description of solid tubes as a "foam noodle" could be turned around
to call air tubes "air noodles."
Question: I've been looking at some product literature for puncture proof, solid rubber inner tubes.
Has anyone used this product, or something similar? What do you think?
Bike shop owner number one's answer: Haven't used it; the idea is unappealing for a couple of reasons, and I'm
sure there are other drawbacks I haven't thought of. Here are a few key observations about installing
solid tubes: If the product is the right size for your tire, installation is no picnic. If
installation is easy, it's not the right size.
Imagine trying to install the tire in between the
tube and rim WITH THE TIRE INFLATED, if a tube existed that would permit such a procedure.
That's what you're doing if the thing is really designed to maintain the same level of effective
inflation tension on the tire bead as would be produced by conventional methods.
- David's answer: What amazes me is that the respondent, above, admits he has never used or mounted
solid tubes, yet he has a negative opinions and erroneous observations about them. He says, "If the
solid tube is the right size for your tire, installation is no picnic. If installation is easy,
it's not the right size." This comment is patently false. I purchased my solid tubes and installed
them myself using two screwdrivers. This guy really has no idea, but he is against
solid tubes, and my suspicion is that he is a bicycle shop owner who wants to kill the idea of
solid tubes to save his struggling business.
Bike shop owner number one's answer: Part of the reason that solid tubes are nearly impossible to mount
is because tension is needed to keep the tire from squirming out of the rim.
- David's answer: "Squirming out of the rim?" "Tension is needed?" The respondent above is making things
up. He admits he is clueless, yet continues to make false, incomprehensible, disparaging
statements.
Bike shop owner number one's answer, continued: If tension isn't maintained, what's likely to happen? If you do
manage to make it work, then getting the tire on to the rim is going to be interesting. Remember
that with the regular tube deflated, what eases the process of getting the tire onto the rim is the
fact that the tire bead can drop into the spoke head area in the rest of the circumference to allow
a bit more room to get the last bit over the edge of the rim. That's not likely to be possible with
solid tubes.
- David's answer: Clues to the probability that this is a bicycle shop owner who fears solid tubes will
affect his business are the technical terms he uses that are not in the average person's lexicon,
specifically, "tire bead," and "spoke head area." Not many bike riders use these terms. Also, note that
he says "That's not likely to be possible with solid tubes," an admission that he is guessing with
absolutely no foundation of experience behind him.
Bike shop owner number one's answer, continued: There's really no such animal as a completely puncture proof
air-type innertube. If you really want to put an end to flats - and endure a far harsher ride,
not to mention being a "bitch" to install - then go with a set of "tubes" made of foam rubber.
- David's answer: The guy is correct that there is no such thing as a completely puncture proof
air-type innertube, which is why people are seeking a better alternative such as solid tubes.
But he is wrong about the "far harsher ride" and "being a bitch to install."
It is true that solid tubes have a slightly firmer ride, but this effect is forgotten
within a few minutes of riding.
In addition, a solid tube can provide better protection to a rim when riding over curbs and
rocks. Air tubes will compress fully if the tire hits the edge at a high speed, possibly causing
the rim to be dented and/or deformed. However, a solid tube can't fully compress because it is solid, providing
an additional cushion for the rim.
His choice of the term "foam rubber" is designed to indicate that solid tubes are cheap and innefectual.
They are not made of foam rubber, as we know it, in mattresses and chair cushions. Again, this guy,
probably a bike shop owner, is trying to steer people away from solid tubes.
Comment from person who asked the questions: I hadn't known about the harsher ride, but
it figures. I think I'll stay with tubes.
- David's comment: Well, the bike shop guy won! He actually dissuaded the questionner from going with
solid tubes!
Bike shop owner number two's answer: If these are some sort of plastic inner tubes that take
the place of an inflated tube, the effect is to eliminate flats but they're hell to get on and
off, actually dangerous once you soap them up and start using brute force tools, when you slip.
- David's comment: Notice that the respondent, above, says, "If these are some sort of plastic
inner tubes . . ." indicates that he, too, is uninformed and clueless. You don't "soap up" a solid tube,
you don't use "brute force tools," and they aren't "hell to get on and off."
Bike shop owner number three's answer: The ride is rough, and I broke a couple of hubs from
the increased shock and vibration. Stay with air, if these are not.
- David's comment: He broke a couple of hubs? The only way he could have done that is to try to jump the
Snake River Canyon, miss, and fall to the bottom, on his bike or by riding his bike out of an airplane.
If he actually broke a hub, he wouldn't be around to tell about it. There is no "increased shock and
vibration." Notice that he says, "Stay with air, if these are not," indicating that he really does not
know what is inside solid tubes.
Bike shop owner number four's answer: You can eliminate most flats by moving to Ohio. I get one
every 4,000 miles out here. It was one every 200 miles in NJ. They're so infrequent in Ohio that I
no longer carry flat tools, and just walk home twice a year instead.
- David's comment: I should think New Jersey residents would be glad his guy moved away. It improved the
New Jersey gene pool. If this guy installed solid tubes, he wouldn't have to walk home twice a
year!
Bike shop owner number five's answer: As we all know, nothing beats Dunlap's Pneumatic Tubes
for comfort and control. (In other words, you want tires that just have air in them!) If you're really
worried about puncture resistance, get yourself some great tires to wrap
around those tubes. I'd personally recommend both the Specialized Armadillos and Continental
Gatorskin tires. And if you can't get that, at least throw a Mr. Tuffy between your tube and tire. That'll
take care of everything but the pinch flats.
- David's comment: This bike shop owner is obviously a distributor of the following items:
- Dunlap Pneumatic Tubes
- Specialized Armadillo Tires
- Continental Gatorskin Tires
- Mr. Tuffy, a puncture resistant cloth
By the way, with solid tubes, pinch flats are a thing of the past!