First, rim width affects tire wear. I’d run standard 19.5 mm alloy wheels and 23 mm tires for the better part of a decade before switching to carbon fiber wheels. And, to be clear, carbon fiber wheels are the cat’s pajamas if you want to average more than 18-mph on your rides. See, when you’re cruising around 16-mph, they really don’t make that much of a difference. When you’re north of 22 or 23, the difference is immense.
There’s another benefit that’s come with carbon fiber wheels: width.
I’ve got two sets of carbon fiber wheels on two different road bikes. I’ve got 38s on my Trek and 50s on my Venge:
The 50s are absolutely superior to the 38s when the wind isn’t howling, but there’s an interesting benefit to the 38s on the Trek and the 50s on the Venge; the rim width of each set matches the chainstay clearance of each bike, almost perfectly so I can use the widest possible tire on each bike. For the Trek, with standard alloy wheels, the best I could run was 24 mm tires. Anything wider would rub the chainstays when I climbed hills out of the saddle. The Ican 38s are 23 mm wide which means I can easily run a 25 mm tire without fear of chainstay rub because the wider rim lessens the “lighbulb” effect of using a wide tire on a narrow rim. I did run 25s for quite some time until I decided to switch to 24s for reasons I’ll get into in the next paragraph. The Venge is even better. The Ican Fast & Light 50 wheels I’m rolling are 25 mm wide so I should be able to fit a 28 mm tire on there. I haven’t bothered, though. I’ve stuck with 26 mm Specialized Turbo Pro tires.
See, the pros use tires equal to or 1 mm less wide than the rims they’re running. 28 mm tires? 29 mm rims. 25 mm tires? 26 mm rims. This is for aerodynamic’s sake. I noticed, however, running 26 mm tires on 25 mm rims greatly improved tire wear. Normally you’ll develop a flat patch at the center of the tire after a few hundred miles that gets “flatter” the longer you run the tire. I noticed the 26s on 25 mm rims didn’t develop the flat patch near as fast – and if I rotated the tires every 700-1,000 miles, having the rear tire on the front of the bike would round it back out. With the Trek, I still had wear issues using 25s on 23 mm rims (though they weren’t near as bad). After I wore out my set of 25s, I changed to 24 mm Specialized Turbo Pro tires.
I got a full season out of the tires on the Venge. They’re about done, but they served me well. Thousands of miles on a tire with an effective life of less than 2,000. The 24s on the Trek did even better. I got a full season on those and I’m not even thinking of replacing them yet. They’re still in excellent shape after having been rotated twice.
I’d heard mumblings about improved tire wear when the rim width approached tire width, but the main benefit was always aerodynamics for those who regularly sprint at 44+ mph. My best sprint with help is around 35-36, so not really my cup of tea, but I wanted to see if rim width affected tire wear.
Now that I’ve seen the extended tire life that’s possible, as long as I can get the right tires, I won’t go back. Tires wear that much better.