Regarding riding a bike, the wheels and tires largely determine your speed. Still, in this sense, tubeless tires and rims can be innovative. With technological advances, tubeless designs have become the fastest road tire and wheel pair available. Choosing the perfect tubeless tire, wheel, and pressure combo can let you boost some more extra speed without exerting extra effort.
Rolling Resistance
Rolling resistance most of all results from the friction created as a wheel moves over the road. A wider tire has less rolling resistance because its contact patch is shorter, broader, and rolls more freely than the longer, thinner, elliptical form of a smaller tire that deforms more as it rolls. Reducing pressures on broader tires allows them to absorb road shocks without compromising as much momentum. Though running wider tires will help to improve speed and efficiency, they must be mounted on bigger rims if so. When a tire is not fitting as firmly as it could be, micro-movements of the rubber on the rim can gather to be very considerable energy losses. On a larger rim, a 25- or 28-mm tire will seat more firmly.
Aerodynamic Drag
The aerodynamic drag an object experiences increases exponentially with increasing speed. Twice as fast as the air means more than eight times the energy is needed. The power of a rider is limited; consequently, obtaining greater speeds without increasing power output requires improved aerodynamic form as the object goes through the air. Good rim shape design helps to greatly reduce the subsequent drag in the wheel and preserve its stability.
On bikes, wider tires have lately become quite more prevalent. About aerodynamics, the width of the rear tire has minimal bearing on matters. Still, the width of the front tire makes more difference. Thus, a 23mm front tire is advised to be utilized independent of wheel design for 25mm tires. Even at speeds above 30 km/h, 23mm tires have higher aerodynamic advantages than 25mm front tires.
Photo: Courtesy ENVE
Why Choose Tubeless Tire
Tubeless tires are safer to use at lower pressure than tubed tires since they lack a tube to get pinched when hitting acute shocks, therefore reducing rolling resistance on uneven ground. Moreover, tubeless tires eliminate the hysteresis and friction against the inner tire casing, therefore lowering rolling friction. The first generation of tubeless road tires was airtight and did not need sealant; the frictional rolling losses were the same even though they had so much rubber coating on their insides that their weight was the same as a similar tire and tube. Still, modern tubeless-ready tires with sealant are lighter and have less rolling friction than tubed tires.
Hooked Rims vs. Hookless Rims
Rims with hooked edges on the inner edge of the rim sidewall exhibit clearly an inward-facing hook or flange. This hook, especially under high pressure, keeps the tire bead in place and prevents it from detaching from the rim. Most rims in the past were built with hooks to suit clincher tires—tires with inner tubes since the hook offered a steady mechanical hold.
A hookless rim is a type of wheel whereby the internal edge of the rim lacks a flange or hook. Its sidewall profile is straight instead and lacks an inward-facing hook. Depending on a proper fit and air pressure, the tire bead tightly contacts the rim. Usually found in tubeless designs, hookless rims are employed where the tire creates an airtight seal against the rim bed without an internal tube.
While hooked rims provide enhanced mechanical lock and security, hookless rims give better impact resistance and easier installation.
Hookless rims might be a suitable fit if you ride on better roads and give aerodynamic considerations first importance.
Tire and Rim Width
For individual contests when time is of considerable importance, we counsel using a 25mm tire in the front and a 28mm tire in the rear wheel. The front tire used should be a minimum 1mm wider than the width of the outside rim. By employing a 25mm tire for the front, most aero rims with an internal width between 19 and 22mm help reduce the aerodynamic drag. Using a bigger 28mm tire has little effect on aerodynamics since the frame spans the rear wheel. It saves many watts of rolling resistance and boosts traction as well.
If athletes wish to perform as best, they are advised to choose low-rolling resistance tubeless clinchers. The tire should be run on a rim five percent wider than the tire itself. But when tire and rim diameters increase, the need for a wider rim loses relevance. This is true because, under yaw, the larger tire radius makes more simple air connection to the rim possible.
The Fastest Setup
First of all, tubeless tires are superior to tubular ones. They have lowered rolling resistance and provided a more smooth transition to the rim, especially on hookless rims. This results in better aerodynamics.
Second, changing the tire width and rim will boost your performance two times. To get optimal aerodynamic performance on the front, use 25–26mm broad tires on rims with 27–30mm (outside width). The tire lines are only a guide, so keep in mind to place the tire on the rim before measurements. On equal width rims, equip the rear wheels with 25–28mm wide tubeless tires. Using hookless rims can help your aerodynamics be considerably better.
