Research shows that 25-mm or even 28-mm tires can be faster. That’s not just due to the width of the tires, though. Wider tires are only faster on wider rims.

“Wide tires only make you faster if you put them on the correct rim,” says Andreas Klier, EF Education-EasyPost Sports Director and Technical Operations and Commercial Manager. “It’s the combination of the width of the rim and the width of the tire that makes the difference.”

EF Education-EasyPost performance staff consider two factors when they determine the ideal tire and rim combination for speed: aerodynamics and rolling resistance. Those factors are always influenced by the rim and tire in combination. The speed of a tire is dependent on the rim it is mounted on, and the speed of a wheel is dependent on the tire that makes contact with the road.

Rolling resistance is mainly caused by the friction produced when a wheel rolls over the road. A wider tire has less rolling resistance than a narrow tire, because the wider one has a shorter, wider, and thus rounder contact patch which rolls more easily than the longer, slimmer elliptical shape of a narrower tire which deforms more as it rolls. Wider tires can also be run with lower pressures, making them absorb bumps from the road without losing as much momentum. Those advantages will only make you faster if you get the benefits of running them on wider rims, though. To maximize speed and efficiency, a tire needs to be mounted as firmly as possible on the rim. Otherwise, micro-movements of the rubber on the rim can add up to significant energy losses. A 25-mm or 28-mm tire will sit more firmly on a wider rim.

That rim-tire combination is also more aerodynamically efficient. On a narrow rim, a 25-mm or 28-mm tire will bulge out from the rim and produce a significant amount of turbulence when it spins through the air, especially as it wobbles slightly on the road. A wide tire will sit firmly upright on the rim. The more vertical sidewalls make for a smaller frontal profile, which moves less from side to side as you pedal and is thus faster aerodynamically.

Our team uses Vision Metron 55 rims in combination with 28-mm Vittoria Corsa Graphene 2.0 28-mm tubeless tires. Vision Metron 55 rims have a 19-mm inside width, which is several millimeters wider than traditional rims. As a result, riders can cut through the wind with maximum efficiency on firmly mounted tires that soar over the tarmac.

“That adds a lot of comfort,” says EF Education-EasyPost pro James Shaw. “With 28-mm tires, we aren’t bouncing in the potholes any more. We can run a lower tire pressure and be more aerodynamic using wider rims as well. I think it’s very important to have a lot of comfort when you ride 170 kilometers average for 21 days.”

At EF Education-EasyPost, we inflate our Vittoria Corsa Graphene 2.0 28-mm tubeless tires to 5.5 bar in front and 6 bar on the back. Mechanic Fred Bassy suggests that you might even want to run yours a little softer for a bit more comfort and grip in the corners, especially when you are training. With Vision Metron 55 rims, you’ll have a WorldTour proven set up that will turn the energy you put into the pedals into speed.