1. Wide rims are more aerodynamic.
A wider rim better approximates the width of the tire. This creates a balance of pressure from the front to the back of the wheel. This results in a smoother flow of air over the wheels and over the bike, which means you will ride faster and more efficiently.
2. Wide rims improve handling.
On clincher wheels, wider rims allow the sides of a tire to spread out into a rounder shape. This improves handling by increasing the consistency of the tire shape throughout different types of turns, especially hard turns. On tubular wheels, the tires are always round (due to the way tubular tires are made), but a wider rim reduces the chance of the tire 'rolling' sideways. This increases the safety of the wheel, and makes it possible for more aggressive turning. There’s less chance of pinch-flatting on wider rims too.
3. Wide rims reduce rolling resistance.
On clincher wheels, the wider rim allows the tire to spread out more. This changes the shape of the tire's 'contact patch', or the part of the tire that’s touching the road at any given time. On a narrow rim the contact patch is a longer, more rectangular shape. With a wider rim, the contact patch is wider, shorter, and more square. The squarer contact patch results in reduced rolling resistance, and increases the speed and efficiency of the bike. It’s for this reason that wide rims offer better grip in poor conditions too.
4. Wide rims improve ride quality and comfort.
Wider rims create larger tire cross-sections, which means more air volume in the tires, resulting in less negative feedback (road shock) from uneven riding surfaces. Many riders take the opportunity to run their tires at a lower PSI with wider rims which makes the above effect quite noticeable.
Are wide rim wheels heavier, and slower?
A wide rim wheel will be a little heavier because more carbon is used in its manufacture. In general, heavier wheels are considered to be slower than lighter wheels. All else being equal, this would hold true, but as you can see from the points listed above, rim weight is only one of a number of factors involved in performance. In real riding situations, the benefit of better aerodynamics, handling, and rolling resistance ’out-weigh :)' the added weight. This is an important point to consider when comparing different wheels. A wide rim will likely be faster than a narrow rim, even if it’s heavier by a few hundred grams.
Ride quality might not have much direct impact on speed but it will impact on performance on longer rides, or on uneven surfaces, and cost-free improvements to a riders quality-of-life in the saddle are welcome!
How wide is wide?
A standard rim is 19mm. Anything more that 23mm is considered wide. At Tokyowheel all our rims are 25mm+. They’re all 25mm wide at the braking surface, so that they remain compatible with different manufacturers’ brakes and frames, but some models angle out to be 27 mm wide thereafter. We based our rim engineering on 'Computational Fluid Dynamics’ - we used engineering software to calculate the most aerodynamic rim shapes possible.
What tire width should be used with wide wheels?
We recommend you use 23c tires on wider rims. Some people choose to use 25c.
Are Wide Rims Better? YES!0