Originally Posted by
jackb
Why couldn't manufacturers come up with a rim brake that allowed for wider tire? I'm sure such a thing is possible.
They exist, they're just not standard for the built kits that component manufacturers send to bike manufacturers.
The best rim brakes in my stable are probably the Deore T610 V-brakes on my gravel bike. I've got them set up above 52mm tires and full-length fenders with healthy clearance to spare. They're as light as 105 caliper brakes, despite being cheaper. They're extremely powerful in all conditions. And when it's not mucky out, they modulate around as well as the hydro discs on my MTB (right now they're actually significantly better, but that's unfair because my hydros are in need of a bleed, whereas I just serviced the V-brakes).
Actually, before the narrow tire fad strangled the market in the 1980s, it was typical for road calipers to be able to handle 35mm tires or bigger. Dual-pivot centerpulls and especially cantilevers could go considerably wider. As far as road bikes are concerned, "rim brakes can't handle wide tires" is more a fashion issue than an engineering problem. The main technical advantages of disc brakes on road bikes are wet-weather modulation and avoidance of rim wear.