Are Tubulars Faster than Clinchers?

Even before you get to the decision of how deep rims to get, when deciding on a new set of wheels, the first question you need to answer is should you opt for clinchers or tubs (tubulars).

There are many Pros-and-cons to each, but it generally boils down to clinchers are easier to maintain, cheaper to buy, but are heavier and don’t have as nicer “feeling” on the road as tubs. Thus it is for these reasons that traditionally most cyclists who race (including pros) will use clinchers for training and tubulars on their race wheels.

However with the advent of wider rims, the integration between a correctly sized clincher tire and the rim is often better than most tubs and their rims and thus they are now considered to be a little more aerodynamic, so could this balance be shifting?

I recently came across this really interesting video (see below) in which Jamie from BikeRadar ran a small experiment to discover if wheels with Tubular tires (Tubs) are quicker than wheels with clincher tires and whilst it is not a massive study under strict scientific and laboratory conditions, it does throw up some interesting points:

Aim

To establish which is faster: Tubular wheels or Clincher Wheels.

Method

Jamie compared the performance of his wheels on three short tests, a time trial, a hill and then a series of short sprints.

Whilst this study was not conducted under laboratory conditions with a wind tunnel for example, he still took great care to control as many elements as possible to get his real world results.

For example on the time trial test, he chose a looped course and on a day with very low wind. He also used a time trial bike to have better control of his position on the bike and for consistency obviously used the same clothing helmet etc. Indeed the only difference was the set of wheels and their tires and even then he tried to keep them as close as possible:

Wheels & Tires
Jamie obtained two sets of wheels and tires (share the same compound) that were as close to each other as possible and at the same pressures, with the only really difference being that one was a clincher and the other a tub:

Clincher: Enve SES 4.5 with 25mm Continental Granprix 4000sII with race lite tubes
Tubular: Enve SES 4.5 with 25mm Continental Competition

The weight difference between these two was 316 garams – so for a flat TT course and even the rather short hill that was used for the test, this should really not make that much of a difference.

The tests were then run to a fixed power, so that both runs on the different wheels were at the same power level and thus fatigue was also taken out of the equation.

Results

Time Trial Test (9.7miles/15.6km) at 305 watts

  • Clinchers: 23:36
  • Tubulars: 23:48

The Clinchers were 12 seconds faster

Hill Test

  • Clinchers: 4:56 @426 watts
  • Tubulars: 5:00 @424 watts

The Clinchers were 4 seconds faster, but there is a tiny difference of 2 watts in power

Sprint Test
9 second sprints ant maximum effort (about 900 watts)
This was subjective as Jamie just went on feel and he does concede that the tubulars felt like they “accelerated a little bit more crisply”.

Conclusions

There is no doubt that this test is eye opening and gives us plenty of food for thought, however we have to remember that it is quite limited in it’s scope.

For example I would really like to see this exact test run with a standard box section clincher wand box section tubular. In this way we could perhaps see if it was just the aerodynamics that made the clincher deep section Enve faster, or if it was the small differences in the tires.

Jamie says that after the test he is now a complete convert and would not choose a tubular wheelset over the same clincher version. However I think that in real race conditions and especially on a hilly circuit or course, with the many accelerations and attacks you get, the weight difference between the two will become a factor. Remember when he tested them, even when climbing, he was just using a steady speed without any sudden accelerations etc.

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