What's your bike+rider weight?

What pressure were you running?

How wide are your tires?

How wide is that rim?

In my experience, a narrow tire on a wide rim is more likely to pinch flat since it's shorter in cross section than the same tire on a narrower rim. I've spent a lot of time on 24mm wide rims with 25/26mm wide tires and have had quite a few pinch flats due to gravel and "golden-bb" type rocks. I've even had two pinch flats on the same tube at the same time. I try to keep my tire pressure to the point that I get 15% sag under load but sometimes it's a little over or under.

It's generally a combination of tire pressure, rider+bike weight and terrain. Your best bet it to up the pressure or increase the tire size.

Or you could always go 650bx42.