Wide rims for rim brakes for gravel bike?

Question

I have a decent gravel bike that I put together from parts. It has cantilever rim brakes and 40c tires. The wheelset is an old Mavic Open road one which has narrow rims. I'd like to switch to a wider wheelset with rims at least 23 mm internal width, but keep the rim brakes. It seems like these must be available as 29er for older mountain bikes, but I'm having trouble finding anything. Can I buy an off-the-shelf set, or should I expect to have to have something built up?

Answer 1

There are a handful of good options. A lot of what's out there in this category is heavy and more for hybrids, 29ers, and touring bikes. A 23mm internal width rim with a brake track basically means a 29er rim, and finding something not excessively heavy might be challenging. The HED Belgium R comes to mind as around the widest rim brake road rim I know of.

Canti cross bikes are limited for how wide the rims can be before the brake setup gets weird. Typically the first thing to go wrong when you push this too far is you won't be able to get the face of the pad to contact the rim squarely. This depends on the post spacing of your frame/fork as well as the brakes chosen. Some cross bikes are more big-tire oriented than others and won't run into issues as easily. True cross race bikes with cantis typically won't play nice with something much wider than about 23mm external, but they also can't typically take a 40mm tire, so maybe you'll be in luck. There are some cross-oriented pads such as Kool Stop Thinlines that exist in part to mitigate these issues as best as possible. Brakes of the "no vertical adjustment" flavor such as the TRP Eurox are the most sensitive to this.

If the goal is to go as wide as possible, one approach you could take is simulate the brake setup with a rider rim by clipping or taping something on to the rim temporarily to bulk them up and see how wide of a rim your brakes can tolerate.