A debate that may last forever, and one that, in my opinion, is only answered by the person riding the tires. However, since I've been asked several times for my opinion on which tire is "Fastest," I will do my best to answer that question with this blog post. It really isn't very exciting, but at the very least it will be informative.
This debate has become a real interesting one. It was never an issue until clinchers started to become so well made.
For triathlon purposes where efficiency both in repair while racing, and accomplishing the fastest time is necessary, I believe a good clincher combined with a latex tube is the way to go. Because most triathletes aren't pro level, but enthusiasts at best, the thought of changing a tubular can be intimidating. Clinchers are easier, and more familiar to the enthusiast to change while doing a hasty repair during a race. That being said, being able to change a tubular or inner-tube is critical, and practicing with whatever tire you choose to ride is a must.
I say that the debate wasn't an issue until clinchers became so nice, because it's the truth. The advent of the "Open-Tubular" which is basically a tubular tire that wasn't sewn together with a tube inside, and instead a kevlar bead was placed which then turned the tire into a clincher. These tires offered the ease of a clincher with the lightweight and "speed" of a tubular. Clinchers were never a "Real" option because they were never as nice as the tubulars. Tubulars used to always be made with silk casing and aged, this combo provided an extremely smooth rolling tire with a very pliable feel. This also gave a tremendous amount of "Road-feel" which could really "tell" the rider where his bike was going....in the past no clincher could ever do that. However, now with the great clinchers available there is really no reason a triathlete should ever "need" to ride tubulars.
For road cycling it may be a different story. For road cycling, tubulars will be properly glued as opposed to lightly glued for triathlon use. This "Proper glue job" of road cycling provides two benefits, 1) less tire squirm and wasted energy(debatable) 2) less likliehood of tire rolling off of the rim in case of a flat. Also tubular wheels are lighter. Tubulars used during a triathlon tend to be "Lightly glued" in order to make changing a flat tubular tire on the roadside much, much easier. Regarding the wheels for both tubular and clincher, tubulars are lighter, carbon clinchers with an aluminum brake track are heavier as a result of the aluminum, and the all Carbon clincher wheels are nice but in order to remain safe under high pressure, the sidewalls need to be slightly more built up to handle the outward force of the clincher tire bead which happens as a result of an inflated tire, and this often results in a slightly heavier wheelset as well. So if you want the absolute lightweight out of a wheelset, get a tubular wheelset. If you are less concerned with weight, unfamiliar with tubulars, or just like the idea of clinchers better, get a clincher wheelset.
So, the discussion could go on and on. Ask me whatever questions you have. I'll list a few tire recommendations both tubular and clincher.
1) Vittoria Open Corsa with Latex tube- Fast but not really durable- risky for punctures
2) Schwalbe Ultremo ZX- Fast and durable. With a latex tube really a great combo. Not highly likely to puncture unless through a pile of glass
3) Schwalbe Durano S or Ultremo DD- Both very durable and fast with a latex tube
4) Conti GP4000- Durable.
1) Vittoria Corsa Tubular- Fast, light, not very durable
2) Schwalbe Ultremo HT- Fast, durable
3) Conti Sprinter- Durable
I will always recommend
that the fastest most durable tire is best for Triathlon, tubular or clincher. It is always heart breaking to see people struggle changing tires(tubulars) or tubes(clincher) just because they sacrificed some durability for light weight or speed. The Schwalbes, in my opinion, are the best all around tires out there, for both triathlon and cycling.
So, for ease of repair on the roadside, clincher. For the ultimate in lightweight wheelset, tubular. For ultimate speed in a clincher....not just in mph, but overall efficiency, a nice durable clincher and latex tube. For ultimate speed in a tubular a nice durable tubular that is truly glued properly. Of course, either way, the practice of changing the flat tires or tubes is a must. For those of you who know the story of the above picture, that is all you need to know.