Clincher vs. Tubeless vs. Tubular, the hunt for the fastest tire
In Formula 1 car racing things are quite simple. Everybody has to use the same tires. If you talk to triathletes it seems kind of similar. What´s the Pirelli for the car driver seems to be the Continental GP 4000 for the multisport athlete. But why ?
- Clincher : everybody knows it and almost everybody has it on some bike. The tire is held in place by a hooked rim which holds the tire. Between tire and rim you have a inner tube which shapes the tire by air pressure.
- Tubular : there is no hook on the rim, but instead the rim has a round bed. The tube is wrapped and sewed into the tire, and the tire / tube unit is glued onto the rim.
- Tubeless : this relatively young system is sometimes misunderstood as a tubular, but that´s wrong. It´s much more similar to the clincher system. Again you have a hooked rim, but there is no tube. The tire has to hold the air, while a rimtape has to seal the rim. The valve is seperately mounted or attached to the rimtape. Basically every clincher rim can be converted into a tubeless rim, but for best performance a „tubeless ready“ rim is recommended. It´s two little hooks in the tire bead will make a perfect tire fitting.
What the frame is for the bike, the casing is for the tire. It´s the basement which influences all charakteristics of the tire, and so deserves special attention. Many tires use a casing made of nylon. Some premium tires use cotton, and some rare top of the line tires use silk. The mesh density is stated in TPI (threads per inch). The finer the mesh and the higher the density, the higher the TPI count. The benefit of a higher TPI count is a more flexible is the casing, so road roughness can be eliminated better. That will make a more supple ride, as well as lower roling resistance and better traction. Tires with a high quality 320TPI cotton casing (Vittoria, Veloflex, Specialized, Challenge, Bontrager , Zipp…) have a great riding feel. Tires with a even finer silk-casing (Dugast, FMB, Challenge) are often seen in cyclocross due to their high level of grip. Nylon casings have their biggest advantage in robustness, so also a tire with a nylon casing can be high quality, even when the TPI count is „only“ 120.
Continental found a creative way to see the world through pink glasses. On some tires like the Grand Prix TT the TPI is stated with 3 / 330 which means there are 3 layers of 110 TPI mesh, which, according to Continental, makes a 330 TPI casing. So, if I have 1000 $ for 1000 days, then I´m a millionaire in the eyes of the Continental marketing guys. Isn´t that great ? However it´s Continentals exclusive idea that stacking will change the density.
Clincher tires (or open tubulars, like some top-end clinchers are called ) have a bead ad the ends of the sidewalls, which is formed with a wire out of metal or Kevlar. Kevlar is ligter and foldable, so it´s used on higher end tires although it doesn´t make any difference for the ride itself.
On tubulars the casing goes all around the tube which is sewed into the carcasse. A protection belt secures the seam.Between the casing and the rubber there is another protection layer, to avoid defects through sharp objects. If you push a nail into a tire, you will feel a strong resistance because of that protection layer. Once you´ve push a bit more you can overcome this resistance, so there is no 100% guarantee against flats. Almost every good road tire, except for some really special TT tires, have such a protection.
The rubber is the final contact area to the road, so of course it´s very important. Rubber compound and profile are main aspects for grip, and in combination with the casing also for rolling resistance. Other than the compound also the thickness is crutial for the lifespan of the tire, but a thicker rubber automatically increases rolling resistance too. A pure race tire with thin rubber has quite an advantage just because of that. When it comes to compounds every tire company tries to impress with fancy names. If you want to know the real differences of ISO Grip, Black Chilli, Gripton …. then you can either study chemicals, or just put many tires to a field test, because once again the personal favourites can vary. Some makers also use multiple compounds, a harder one for longer life and less resistance in the middle, and a softer one for higher cornering grip on the outside of the tire.
Rolling resistance is for the most part a result of tire deformation. At the contact point to the ground the tire isn´t round any more, but there is a flat section. The power that you need to overcome this section is the resistance you have to keep low. Of course not only the tire is deformed but also the inner tube, so it has some impact on rolling resistance too.
Everbody knows that you can have a great effect on tire deformation by the tire pressure. However you can´t completely eliminate it. And another problem acts against it. The road isn´t smooth , but rough, so the tire also needs the ability to react to the road. If this isn´t possible you will get a harsh and uncomfortable road feel because the tire doesn´t roll over bumps, but instead hits and jumps over such obstackles. All of this can also be seen on MTBs, but much more obvious. Riding uphill a technical trail is much more difficult with too much tire pressure, because the traction is decreased massively.
Like mentioned above a good and flexible casing can help, because deformation can be overcome more easily. Also a wider tire can help, because with the same air pressure the wider tire will roll better, because the force is distributed to a larger volume, and so the contact point to the road (the red marked area in above graphic) will be shorter. However, the benefit on rolling resistance that a larger tires will bring on the front wheel is immediately lost to an aerodynamic disadvantage.
Many triathletes seem to worry a lot about puncture protection. The question is: for which race ? The RAAM ? If you go into a race with a good and healthy tire, the risk of a puncture is quite low, even on an ironman distance. If you happen to hit a nail or glass, then the „bullet proof“ tire might loose air just like the speed weapon. But the deticated race tires are made for a lot lower milage. Most likely it´s due for replacement after 500 miles while another tire makes a couple thousand miles. So for the lifespan of a training tire or dirty roads a good puncture protection is nice to have. In racing every athlete can decide by himself if this is more important than speed. In 2014 Jan Frodeno (current Ironman champion) was riding a tire of his former sponsor Specialized which is said to be one of the fastest tires out there. This tire is used by TT Champion Tony Martin, 24h record holder Christoph Strasser, and some other insanely fst riders. But after Fodenos punctures in Frankfurt and Hawaii some so called „experts“ recommended him to buy Continental tires privately. At Ironman 2015 Andi Raelert and Nils Frommhold flatted, both on Continentals. To believe you can buy security through tire choice is an illusion. By the way, a flat tire can also be caused by the tube or a bad rimtape without the tire having any influence on it.
Advantage and disadvantage of tire types
The biggest advantage of clinchers is the easiness. Almost everybody can somehow handle it or replace a inner tube. In training or especially training camps it´s important that after a tube exchange the bike is immediately fully usable again. You also have a great selection of tires, tubes and spare parts basically everywhere in the world. But compared to tubulars and tubeless tires the clincher has the highest risk of punctures, and replacing a tube in a race is rather slow, because you have to check the rimtape and also the tire for debris. If you don´t check, but just install a new tube, you will end up on the side of the road again just a few minutes later. If this is the reason for 3 punctures in 1 race ( for example the ironman in Frankfurt) then this is NOT bad luck, but just inability of the rider (I do not know that the reason for Frodenos 3 punctures at IM Frankfurt 2014 was in detail).
Many of the advantages of tubulars don´t come through the tires but because of the rims. Since the rims don´t need the horn they are not just lighter but also a lot stronger. With no horn also the risk of snake bite punctures is less than on clinchers. Tubulars also have decent ability to ride on a flat tire, so you can keep on riding for a couple of miles if you have the hope to be saved by a neutral material support in a race. In cyclocross you can ride tubulars on extremely low air pressure because the tires are glued to the rim. And in a race a tire exchange is fairly quick if you can get the tire off the rim well (which sometimes can result in bladders on the hands). But a replaced tire during a race is not glued, so it´s not fully loadable. It´s enough to finish the ride but not for high cornering speeds. The glueing process takes more time and a bit of experience, unless you use tapes like Tufo or Veloflex which make tire glueing a piece of cake. Tubulars are also said of having a very supple road feel, but good clinchers are not much worse nowadays. However, in pro cycling you barely see anything else but tubulars.
Tubeless tires have a main advantage when it comes to rolling resistance: no tube, no tube deformation. Since there is no tube the risk of a puncture is extremely low too. Small holes are immediately sealed by the milk in the tire. In case of a puncture you can still put in a tube to finish your ride. One problem of tubeless can be the assembly. You have to get the tire to seal the sidewalls to the rim. Sometimes it might need high pressure (compressor) to do so. The selection of tubeless tires and rims is also still limited. The benefits of rolling resistance and puncture protecion could make it the system of the future.
So, hands down, which is the fastest ? That´s not a question of tire system, but of the tire specifically. In a tire test in the „Triathlon“ magazine 2014 a Continental GP TT clincher (Race tire with limited milage) was tested vs. a set of Continental Attack / Force tubulars (grippy rear tire with high comfort and milage). If you want to know which one is faster, you don´t need a test but only a tiny bit of brain and common sense. And of course it doesn´t make sense to declare a magazine test winner as the fastest tire of the world, because you would have to test the best tires of ALL brands. So instead of a standard magazine test with 10 to 15 tires you´d end up with a test of 50 to 60 tires to make a finall decision (on neutal ground, and not in the lab of a certain tire maker). The Conti GP TT isn´t even the fastest Continental since the rolling resistance numbers of the GP Supersonic are even a bit lower. Many tire brands have tests done at „Wheel Energy“ in Finland, which is a neutral company.
Continental keeps on saying that clinchers have a lower rolling resistance than tubulars. In the „Triathlon“ magazine test 2015 they tested the Attack / Force combo in clincher and tubular, and the Conti claim was confirmed… for this tire. Other brands also had clinchers and tubulars on test, and for many the tubulars were the faster option. The Michelin Pro 4 tub had better results than the Pro 4 Comp Limited clincher, and the Vredestein Fortessa Senso AW tubular was 6,5 Watts faster than the similar named clincher. Not only cycling pros, but also many tire makers such as Specialized call the tubular the best choice overall. The Tangente SL Speed tire of aero specialists Zipp is only availlable in a tubular version.
Nevertheless many other tire brands agree with Continental. One example is Bontrager whose R4 / 320 clincher (with latex tube) has the least rolling resistance of the Bontrager lineup. After the R4 Aero clincher (with latex tube) the R4 Tubular comes in third.
However sometimes it´s very difficult to compare, because details and carcasse can be different on tubulars and clinchers. Maxxis has completely different tires for the 3 tire systems, and although Maxxis is one of the pioneers in tubeless, the fastest Maxxis is currently the Relic TT clincher. One reason can also be the higher sales of clinchers, and the fact that their tubeless tires were built with more allround characteristics in mind.
One thing is for sure: when speed is desired, there´s only one choice for inner tubes. Latex tubes are significantly faster than butyl tubes. The comparison of Michelin and Vredestein above would likely be different if the clicher test had been run on latex tubes. Also Continental supplies tubulars with latex tubes to their Pro Tour teams, while standard sale tires are only availlable with butyl. Not all tire brands recommend to use latex tubes in clinchers because the latex tubes are highly flexible, so the can get pinched between tire and rim more easily. However, I haven´t had any bad experience of this kind so far.
For many the tubeless sytem is the future, like Schwalbe and Hutchinson who declare a lower rolling resistance for their top tubeless tires „Pro One“ (Schwalbe) and „Atom Galactic“ (Hutchinson) compared to other models. Also Vittoria replaced their extremely fast „Crono Evo“ tire with the „Corsa Speed“ whis is availlable in tubular and tubeless. With adding the new mateial Graphene into the rubber compound (not only for the Corsa Speed), the rolling resistance is said to be dropped drasically, which makes the Corsa Speed Tubeless to the best rolling tire in the Wheel Energy database. Many Pro Tour teams, like the 2 german teams „Giant_Alpecin“ and „Bora-Argon18“, are on Vittorias, so it´ll be interesting if we see tubeless tires more often in pro racing next year. The swiss team IAM has already tested Schwalbe tubeless tires at Paris-Roubaix, but in this case not primarely because of the lower rolling resistance but because of the excellent puncture protection. This proves which pontential this tubeless system can have.
If you got the impression that I have some kind of battle with Continental, that´s not true. I have ridden several Contis so far and only one of them was a big disapointment. With many others the experience was really good. In the segment of less expensive training tires I found tires like the „Ultra Sport“ to feel much better than many other „cheap“ tires. Also the Attack / Force combo is one of the best clincher sets that I know, and I think they are much better and more racing like than the GP 4000. It might make sense to change the width to adopt them better to modern rims. Instead of 22 / 24mm I´d like to see like 24 / 25mm. They are for sure a great allround tire for riders using them in training and racing. For pure racing there´s a bunch of tires that I´d prefer. Continentals customer care however is very positive and worth mentioning.
What surprizes me is the missing personal interest that many athletes seem to have in own experience. Some pay hundreds of dollars for Ironman fees, new shoes, clothing, whatsoever. Why not trying different things in tires as well ?
I don´t want to tell anybody what to buy, because just like any other piece of equipment the personal preference can be different because of many factors. But I wish more athletes would start to use their brain again instead of a magazine test when buying tires.