M Sport said:
Really? Who told you that? I have seen data showing clinchers have marginally better rolling resistance.
Well I would say it is a debatable subject Tubulars v Clinchers. Each have there pros and con's. When I said "supposed to have a better rolling resistance than clinchers" I do mean a lower rolling resistance.
The GENERAL CONSENSUS it seems, is that Tubulars have a lower rolling resistance than clinchers, due to there higher tire pressure inflation rates and therefore provide a lower rolling resistance. Thus there popularity amongst bike racing enthusiasts.
You said " I have seen data showing clinchers have marginally better rolling resistance " I am sure You have. But where ? Is is analytical data from specially conducted tests that show the results on Graphs?
Rolling resistance in tires come down to the surface You are cycling on. The pressure that the tire is inflated to and the type of compounds that it is composed of.
Here are a couple of websites that state that Tubular Tires have a better rolling resistance ( lower rolling resistance ) than clinchers.
http://www.ultracycling.com/equipment/wheels.html
Scroll down the page to where is say's > Tires: Clincher vs. Tubular .
Take Note:>
There are clear advantages to both types of tire here, and whichever you use is mostly a matter of personal preference. Tubular tires, overall, provide a better ride (there's a reason that more pros use tubulars!). Quite simply, tubular tires have higher tire pressures, and therefore, lower rolling resistance. This also provides them with a more comfortable ride.
Her is another Link:>
http://www.ride-strong.com/clincher-vs-tubular-tires/
Take Note:>
Clincher Cons:
Cannot inflate with as much tire pressure increasing roll resistance – some would debate if higher tire pressure makes a difference.
What is interesting to note also from the above is - some would debate if higher tire pressure makes a difference. WOULD DEBATE ? Where is the analytical data to support this Debate.
Tubular Pros:
Better rolling resistance due to higher inflation limit.
In all reality there probably are not much difference Between Tubulars and Clinchers in regard to rolling resistance.
Then if you have a look at Sheldon Browns Website at this link:
http://www.sheldonbrown.com/tires.html
Scroll Dow To Tubulars:
Tubular Cons:
It states : > Tubulars have higher rolling resistance than the best clinchers.
Then if You Scroll Down to:> Rolling Resistance:
Rolling resistance does decrease "THEORETICALLY" with any increase in pressure, but with modern, high-quality tires the rolling resistance at correct inflation pressure is already so low that the infinitesimal reductions gained are more than outweighed by the trade-offs.
The above From Sheldon Brown's WEBSITE totally contradicts the consensus of the other two websites from above.
But if You add rider weight into the above equation that complicates matters even further. Plus smooth and roughly surfaced roads.
There are alot of things that effect the rolling resistance of Tires.