The following will define rolling resistance and discuss its measurement techniques and influencing variables. Although road cyclists generally worry about rolling resistance, experts will also explain why it matters for mountain bike and gravel riders. They will also present three of the best low-rolling-resistance road bike tires found in their tests.

What Is Rolling Resistance?

Tire maker Schwalbe defines rolling resistance as the energy lost during tire rolling. There are several origins of this energy loss, mostly from tire deformation-induced dissipating of energy. Riding on smooth asphalt is far simpler than on gravel or off-road areas since friction between the tire and the road surface also adds to this loss. 

Relative displacement or tire deformation produces heat and noise, wasting system energy. In cycling, tire deformation degree is influenced by elements like air pressure, width, and diameter. Other elements also matter: tire flexibility and the rubber compounds applied in the tread. 

By substituting silica for part of the carbon black in tire formulations, energy loss from relative displacement can be minimized, hence lowering rolling resistance. This is the reason silica is sometimes found in high-performance tires. Additionally claimed to have a comparable impact is graphene, which Vittoria uses in her high-performance tires. 

In a time trial or a race, you could be ready to give up tire lifetime and puncture protection in order to increase speed. Usually with thinner treads and sidewalls, racing tires may even lack layers of puncture protection. Conversely, if you simply detest changing flats mid-ride or ride on tough roads, you could choose tires with extra puncture-resistant layers even at the expense of more rolling resistance for improved flat protection, grip, and tire lifetime.

Why Is Rolling Resistance Important?

One of the most important factors slowing you down when riding is rolling resistance; fortunately, it is also one of the easiest forces to control. Apart from air resistance, rolling resistance explains a significant part of the difficulty you face while cycling and can even overcome air resistance at slower speeds.

Nearly every cyclist wants to ride with less effort, faster speed, or greater distance. One of the easiest and most reasonably priced approaches to accomplishing this is lowering rolling friction. "Cyclists have very limited physical energy," Schwalbe observes, "and they want to use it as efficiently as possible."

Although low-rolling-resistance tires are rather cheap, you can also maximize your current riding conditions and paths, which comes absolutely free.

How is rolling resistance tested?

Mounted on a test wheel, the test tire is blown to the specified pressure. After that, the tire comes into contact with a test drum, and pressure is applied from above to replicate the rider's weight, therefore deforming the tire.

The rolling resistance of the tire is found by the system using the additional power or torque needed to sustain a given rotational speed. Usually, several measurements are done to guarantee consistency and correctness. Before testing, a warm-up sometimes consists in stabilizing the system and tire.

For bicycle tires, rolling resistance is often stated in watts (W), a unit familiar to riders and aficioners. Alternatively, it can be stated using other measurements, such as the rolling resistance coefficient (Crr), computed by dividing the force needed to overcome rolling resistance by the wheel load. Usually, this comes out as N/kg.

Comparison of Rolling Resistance Between Clincher Tires, Tubeless Tires, and Tubular Tires

The friction between the inner tube and the outer tire—which results from their deformation under load—is one component influencing rolling resistance in bicycle tires. Rolling resistance and other influencing elements were measured in tests. Combining 25mm Continental GP5000 STR tires with 10 varying TPU, latex, and butyl inner tubes, the researchers compared their rolling resistance with that of tubeless tires.

Using inner tubes reportedly raised rolling resistance by 0.2–3.8W over tubeless configurations. While most TPU inner tubes surpassed butyl inner tubes, latex inner tubes had the least effect on rolling resistance. Tubeless tires provide the best riding efficiency, it turned out. Using the non-tubeless GP5000 clincher tire is advised if inner tubes are desired since it is faster, lighter, and less expensive.

Though they are more costly, tubular tires work just like clincher tires. Their rolling resistance is like those of clincher tires fitted with latex inner tubes.

Although cotton casing tires also help to reduce rolling resistance, the effects can vary depending on the type and amount of adhesive used as well as drying time. This makes it challenging to come to firm decisions based on comparison tests.

Generally speaking, tubeless tires and latex, or TPU, inner tubes have very little rolling resistance difference, thus riders may choose depending on their taste. Besides, tubeless tires provide additional puncture protection, and the sealant lets cyclists ride home in most cases—even after a puncture.

How Does Rolling Resistance Change With Tire Width?

Experts on two varying widths of the Pirelli P Zero Race TLR tires—26mm and 30mm—did a comparison test to see if wider tires accelerated. The outcome is thus dependent.

On indoor rollers, the 30mm tire needed less power to sustain the same pace while both tires ran at the same pressure. This is so because, with its shorter and wider contact patch, the wider tire deforms less at the same pressure. The smaller tire proved more efficient, though, when the actual tire pressure was changed to the same amount. The rolling resistance would be the same theoretically if you could precisely change the pressure for every width to preserve the same contact area.

On better surfaces in real-world riding, wider tires are not slower than narrower ones. Wider tires speed over tough terrain when compliance and grip are critical. They give more contact area for cornering and improved cushioning. This clarifies why many top gravel riders choose ultra-wide tires for demanding off-road events like Unbound.

Tire size should be selected according to your riding terrain and objectives.

Is Rolling Resistance Important for Mountain and Gravel Bikes?

The quick response is: while still critical, it's not as so as for road bikes. Many mountain and gravel riders might not give rolling resistance top attention. Often thinner or lighter, tires with reduced rolling resistance could be more likely to puncture—a compromise not worth it on demanding courses or endurance competitions.

In XC racing, when speed is crucial and the terrain is not too challenging, mountain bikers should weigh trading some grip for less rolling resistance. Likewise holds true for gravel biking under some circumstances.

Usually, grip and puncture resistance are more crucial for most mountain and gravel rides than reducing rolling resistance.

Fastest Road Bike Tires of 2024

Previously, experts thoroughly assessed many tires and have now chosen eight of the best-performing 700x28c tires. Their rolling resistance was evaluated at the esteemed Silverstone Sports Engineering lab in the UK.

A torque meter to gauge rolling resistance and a drive motor comprised the testing equipment. Real-world riding tests were also carried out to assess ease of installation and performance.

These three tires have the lowest rolling resistance. Still, reduced rolling resistance is not everything. Challenge's Criterium RS tires, for example, showed great riding sensation in real-world situations and did remarkably well in lab tests. Many riders may be discouraged, meanwhile, by their notoriously complex tubeless arrangement.

Pirelli P Zero Race TLR

Measuring just 11.86W, this Pirelli tire attained the lowest rolling resistance in the tests. Early 2023 saw the most recent improvement with thinner sidewalls and aramid fibre inclusion into the material, therefore enhancing puncture protection and perhaps lowering rolling resistance.

Although the shape of the tire is somewhat thin with a rounded profile, which slightly affects handling, comfort is not compromised. It still presents first-rate grip and riding quality. At 310g, the 28mm variant is rather heavier than some rival tubeless tires.

Recently, Pirelli also debuted the P Zero TLR RS, which claims lower weight, less rolling resistance, and better fit with hookless rims.

Schwalbe Pro One TLE

With a rolling resistance of 12.08W, the Schwalbe Pro One TLE tied second among the eight tested tubeless tires. Two main claims made by Schwalbe's introduction of the newest version were improved cornering grip and reduced rolling resistance.

The revised Addix Race rubber compound and the redesigned casing design contribute somewhat. Among its class, the 28mm variant tested weighed 264g per tire, among the lightest models. On the road, it seems quick; testers even traversed several hundred kilometres on gravel surfaces at pressures as low as 40 psi (2.7 BAR) without any problems.

Challenge Criterium RS

With a power reading of 12.18W, the Challenge Criterium RS locked the last podium place in the rolling resistance trials. With a flexible, high-thread-count cotton casing unlike the nylon used in the top two candidates, it is remarkably lightweight at just 263 g per tire.

Though installation and maintenance were very difficult, testers valued its comfort and grip as well as its sense of freedom brought by its low rolling resistance. Some riders may find this tire appealing only in 25mm and 27mm widths; hence, its availability may be restricted.

How Reliable Are Rolling Resistance Test Results?

Notably, most of the evaluated tires had very small rolling resistance variations. On a bike, several other elements can affect the efficiency of a tire, including tire pressure, internal width of your rims, and combined weight of you and your bike.

The testers controlled variables using latex inner tubes at 80 psi, although for some rim/tire combinations this pressure could be too high. The Zipp 454 NSW hookless rim, for example, has an internal width of 23mm—much wider than the 20mm internal width of the Hunt 54 Aerodynamicist Carbon Disc front wheel used in the tests—and a pressure limit of 72.5 psi (5 BAR). Both could change rolling resistance.

ISO criteria define a consistent rolling resistance measuring technique in the automobile sector. The testers decide the approach for tests on bicycle rolling resistance. Still, experienced testers offer the most thorough and consistent testing strategies.

The main lesson is that rolling resistance, aerodynamics, durability, and grip are always traded-off. You will have to carefully weigh these elements when choosing which tires to utilise and at what pressures or conditions.

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