Tubeless watch out
The pneumatic tire, technology developed for bicycles, is an amazing invention. In the 135 years or so that it’s been commercially available, there hasn’t been much in the way of advances. The first pneumatic tire for sale was supported by a bonded canvas tube, sealed with rubber and glued to the rim, pretty close to a modern tubular tire The second one, which also came out in 1889, had a leather exterior and latex rubber interior, as butyl rubber wasn’t developed until 1937. The clincher tire design was first patented in 1882 and another version in 1890. Tubeless pneumatic tire technology was first patented in 1898; again, it was for bikes. But it went nowhere. Tubeless tire technology for cars was developed in 1952. Tubeless bike tires weren’t realized for 101 years, when Mavic, Michelin, and Hutchinson teamed up to introduce Universal Standard Tubeless , which works without sealant, in 1999. It was first for mountain bikes, then road, and quickly thereafter “tubeless-ready” setups with sealant started appearing, largely thanks to Stan Koziatek, and has grown to be a huge part of the market.
Rubber inner tubes are amazing tech. They’re simple, durable, light, cheap, easy to install, remove, repair. They take little attention and can last for years. Which is probably why, even with the advantages of tubeless, tubed tires still hang around. Of course, they were cutting edge tech once, and probably had issues that were worked out over time. That development period may well be lost to history.
Tubeless bike tech has its pros and cons. As do all pneumatic tire systems. But tubeless popularity has been a huge boon to TPU bicycle tubes. And could be ushering them in as the next big thing for tires.
TPU Basics
TPU, short for Thermoplastic Polyurethane, is a polymer that can be turned into products possessing properties of both rubber and plastic. It can be rigid, it can be flexible, it can be somewhere in between, depending on how it’s done. It’s found in running shoes, cars, medical devices (including heart valves), and many, many other places.
The first TPU bicycle tube appears to be from Eclipse, which debuted their offering in 2011. TPU bike tubes seem to have first started showing up in the United States in 2017 when Tubolito brought their product to market. These TPU tubes were much lighter than latex (25-45g for 700c TPU road tubes vs. 60-80g per tube for latex, and 80-120g for butyl) and were almost as fast. They held air about as well as butyl, which means much better than latex. TPU tubes are generally lighter than the tubeless sealant needed to keep an identical-sized clincher tire airtight and can be installed inside a standard clincher tire, making the overall setup much lighter. TPU is much thinner than latex or butyl, so they can be stored in less space.
TPU also might be better than butyl and latex rubber tubes from a sustainability standpoint. Possibly much better. It seems that the production thereof not only uses less material, but also much less water. The materials themselves can be less toxic. TPU, as a category, can be made biodegradable, and at least some companies claim to be making their TPU tubes to degrade naturally. That’s no small deal when it’s estimated that 10 million bicycle inner tubes end up in United States landfills every year. TPU can be recycled with plastic recycling, though it’s unclear if many municipal plastic programs actually go to recycling, and if the recyclers would know what to do with a TPU tube. Tubolito and Eclipse, among other TPU sellers, discuss a “closed loop” system wherein they take back destroyed TPU tubes, but that seems seriously limited to very few places in Europe.
When they first hit the market, TPU tubes were very expensive. Many found them fragile, aka easy to break, when installing. Some claim TPU, even the thinnest tubes, are more flat-resistant than rubber; while there are some videos trying to prove as much, the “proof” I’ve witnessed thusfar never seems to be directly applicable to specific case use. Others claim that the material is tougher to pinch-flat. For whatever reason, there was enough interest that TPU stuck around. The seemingly small success convinced other companies, many already producing butyl tubes, latex tubes, tubed tires, and tubeless tires to sell, and perhaps develop, their own.
TPU is almost everywhere and yet
Since it took tubeless a long time to actually go into production and a while after that to gain traction for off-road applications, it makes sense that it will take a long time for TPU, if it is any good, to have serious market penetration.
Right now, one can easily find TPU tubes sold by tire purveyors Continental, Pirelli, Rene Herse, Schwalbe, Vittoria, WTB, among others, air experts Silca, and tube brands Barbieri, Bike Tube, Revoloop, Wheel Science, and others. There also seems to be a healthy business for seemingly otherwise anonymous brands on Amazon, Ali Express, and eBay, like Ride Now. Most bike brands haven’t debuted their own TPU tube, which is a bit of a surprise when the big three, Giant, Specialized and Trek seem to sell most everything else. The only bike company I found selling TPU is State Bicycle Company, a brand that seems to focus on reselling and marketing.
That TPU tubes are being sold by so many outfits could be the result of a number of factors. The companies are perhaps hedging on the future. Allegedly, TPU tubes are relatively easy to produce, though looking at all the variations, it seems just as possible that many different brands are using the same factories. Perhaps they’re just trying to keep their customers sticking with the brand, and they can buy or make a relatively small batch of tubes at a time, can gauge success as they go along, and modify based on experience and feedback. Or it could be that they see TPU as the right tool for certain applications, and are producing them not so much for everyone to use, but for certain riders going for certain performance attributes.
A major element of TPU success could be that they are easy to pack, particularly for high-volume tire applications, gravel and MTB—where it seems to have had the greatest market penetration. For many, while tubeless tires offer real benefits, a real drawback is that if you have to repair a tubeless tire out in the field, you might not be able to ride out of the wilderness or ride home. In the days of tubed tires, you could carry a single tube, a patch kit, and a tire boot and make it home from a multiple-flat ride. TPU can pack down to 1/3 the size of a conventional butyl tube, so you can have that five- or six-flat day on tubeless tires and still make it back. Or, if you want to keep the bike and your repair kit super-minimal, you’ve just saved lots of space and weight.
The price of going tubeless
Another element that seems to help grease the acceptance of TPU is the price of going tubeless. Setting up a bike with tubeless tires at a bike shop can cost upwards of $60 a wheel, assuming you already have a tubeless tire, which itself is frequently more expensive than a tubed tire. Then, for those who don’t want to do the maintenance themselves, not uncommon as many tubeless tires are hard to mount and harder to remove, it’s another $30 a wheel or thereabouts every three-to-six months to refill the sealant. Suddenly a $35-45 tube, which seems to be roughly the price (at the time of this writing) across premium brands, doesn’t seem so expensive. But, yes, compared to a $12 butyl tube, even a $22 latex tube, TPU still is pricey. And butyl tubes work great. It gets trickier when looking at value brand TPU; prices are more like $8-25 per tube.
I have mixed feelings about road tubeless. For occasional-use wheels, it seems like a bad idea. For daily-use wheels, I’ve gone back and forth from tubed to tubeless many times. It can work great; I’ve gone through the winter on thin tubeless race tires without ever getting a flat. However, setting it up can be a pain—you need more tools and more time. You need a blast of air to get the tires mounted, necessitating either large C02 cartridges, an accessory air cannister, a special pump, or an air compressor, in addition to valve removal tools and perhaps a sealant injector along with a tire jack. In my time on tubeless, I’ve found some tires leak air more quickly than butyl tubes, and switching tires has occasionally meant I’ve had to retape—mounted the new tires, installed sealant, and found that the old tape/dried sealant had been disturbed by tire removal so that I’ve needed to remove sealant, remove tire, remove tape, and start over. I’ve also had to replace a spoke on a tubeless wheel, which means all that all over again. Tubeless is more setup work than tubes, and the benefits, fewer flats and possibly marginally lower rolling resistance, don’t always seem to outweigh the hassle they present. If you get a flat on your tubed wheels roughly every three months, you’re basically keeping pace with the sealant replacement interval, and a patch with a tiny quantity of glue costs much less than a bottle of sealant, and usually takes less time to repair. If you like the idea of switching tires for different applications, then tubeless can be a real pain as well as a big consumer of sealant.
Looking good
Considering the benefits, TPU looks great. Lighter than butyl, latex, tubeless sealant. Rolls almost as fast as latex. Holds air as well as butyl. Takes up a fraction of the space in a saddle bag. The production is less intensive, less toxic, and the discarded product can be recycled.
But, if one is going to be trusting their life to a new technology, it’s helpful to know exactly how the product works and what its limitations are. Installing a new product in the field for the first time, one should be 100% certain they’re installing it properly and it won’t fail on install or worse, when riding. Installing at home is often easier, but the risk of having a tire/tube fail is such that it’s probably best to know exactly what you’re getting into before you buy new tech.
I’ll address the concerns in Part Two.