Though traditionally a more conservative company, Campagnolo has lead the way in promoting 2-way "tubeless" clincher wheelsets. Shimano and Campagnolo's subsidiary company, Fulcrum, also have 2-way offerings. Cycles BiKyle agrees, this technology is the future. However, at this time there is a small drawback: only one of the high quality tire makers is keeping pace. To date, only Hutchinson from France is offering premium road tires designed to utilize this new format.
Definition: A true 2-way wheelset is specially constructed to accept BOTH standard clincher tires with inner tubes AND the new tubeless clincher tires. Genuine tubeless tires are constructed with special square shaped beads made of extra strong, unstretchable Kevlar. These beads fit securely into square shaped "clincher beads" on the wheels. Additionally, tubeless rims are made with no interior spoke holes so air can't escape. And, the wheels come with a proprietary air valve that sits inside the tire so the tires are easily inflated with any standard presta pump. Presta valves (in contrast to automobile Schrader valves) are the skinny valves used on all but the most entry level road bikes.
Advantages: As tires rotate over the road surface traditional tubes undergo constant movement inside the tire. This movement creates friction that decreases efficiency and road feel. The difference in feel is quite noticeable and independent tests show an actual decrease in tire friction of approximately 30%! Equally important, it's impossible to get a pinch flat on tubeless tires. Therefore, tubeless tires can be run at pressures 10-20 psi lower than standard tubed tires. Once again, independent tests show that lower pressures are more efficient.
"Cars have suspension. Before suspension they probably recommended running lower pressure for a smoother, faster ride. Super-hard tires deflect off of inconsistencies in the road leading to wasted energy and a skittish ride. They rob you of forward propulsion and make you fight the bike. Lower pressures bring a smoother and more natural 'flow' to the ride. In the past, running lower pressures in your bike tires ran the risk of getting pinch flats. Without a tube, this is no longer a concern. Mountain bike riders have been extolling the virtues of lower pressures through tubeless for years now. Cyclocross racers ride with as little air pressure as possible. With road tires it appears to be more subtle (running 10-20 pounds less than tubed versions), but still highly noticeable." Hutchinson Tire Tech
Installation: Tubeless tires are installed in a normal manner, sans tube*. Campagnolo and Cycles BiKyle recommend using a clean brush soaked with soapy water to cover both the tire and rim beads after installation. Before the tire is inflated, push the bead of the tire back towards the other bead while running the soapy brush around the wheel. The soapy water makes it easier for the tire to fully seat into the rim bead. Then, incrementally inflate the tire in normal manner while carefully checking for a solid seal around the entire wheel, both sides. For extra insurance - immerse the wheel, section by section, into a basin of water to check for any leakage.
*We've heard several reports of difficulty installing new tubeless tires. According to these reports, tubeless tires are extra tight so getting them over the rim bead can be a struggle. Truthfully, at Cycles BiKyle we haven't experienced this. In order to hold the high air pressures currently in vogue nearly all high quality road tires provide a very snug fit. However, we have not found any extra difficulty in mounting tubeless tires. Using only hand pressure and perhaps some nylon tire levers on more stubborn tires, our BiKyle mechanics typically mount either style in apx 1-2 minutes per tire. And like tubed tires, a used tire has stretched enough to make future installations quite easy, even without tire levers. If you have trouble mounting a tire do not resort to metal tire irons as these can damage the tire beads. And never use metal tire irons on full carbon rims.
Installation tip: Sometimes a new tire won't seat properly. This is due to bead deformities caused from being folded up in packaging. For a new tire that won’t fully seal: put a tube in it, fully inflate to 120 psi then leave sitting for a day or two. This will smooth out the beads. Then, take the tube out, soap the beads, put in the tubeless valve stem and a couple tablespoons of sealant, if desired, then pump it back up.
Sealant: For even better seal, use a specially designed liquid tire latex instead of soapy water. As an extra precaution, put some sealant around the base of the stem before installing the tire. For protection against future flats, a couple tablespoons of the liquid latex can be dropped inside the tire. Then, rotate the wheel by hand to thoroughly disperse the latex around the tire's inside surface. This sealant will actually seal small punctures on its own. If you suspect a small puncture while riding, slow down but continue riding the tire. In a matter of minutes the sealant will find its way to the leak and seal it automatically. Resume normal speed then ride home like nothing happened! Dependable sealants are made by Hutchinson, Caffe', Vittoria, Stans, and others. From our road testing, Caffe' appears most preferred. Note, however, Hutchinson states that their tire warranty is voided if anything other than genuine Hutchinson sealant is used on their tires.
Tire sealants work well to seal all but largest of punctures (up to apx 4mm). However, never use a sealant that contains ammonia or sodium hydroxide as these can breakdown tire compounds. It has been reported that older Stan's sealant included these harmful chemicals, but current Stan's is fine.
Once a year or after 3 uses of sealant, remove tire and peel away any excess sealant that has hardened into skin-like strips. Then, carefully wipe entire rim and tire with a clean cloth removing any grease or contaminants. Remount tire and install new sealant
Tire replacement: Once a tubeless tire wears down enough that you can see the casing then it will no longer hold air. Like with a conventional tubed tire, it's tire for a new tire.
Weight: tubeless tires require somewhat thicker and more thoroughly sealed casings and treads. Therefore, they are by themselves, apx 79-90 grams heavier than conventional tubed tires. However, deduct the weight of a tube (typically 80-100 grams) and the riding weight is nearly the same.
Cost: Due to the special Kevlar beads, tubeless tires currently cost about $20 more per tire. However, you can deduct the cost of a tube for each. And, the added security and flat protection of tubeless tires should be considered in the cost equation.
Currently available tubeless tires: