we run specialized sawtooth at 42mm width (they also have a 38mm) they are reasonably durable and a very comfy ride. They are also rated up to 80psi(tubed). Ive run them with tubes and tubeless 70 psi on the rear tubed or 55psi max tubeless, flats haven't really been an issue but if running tubeless you need to run them up to max the rim is rated for to mitigate the beating the sidewalls get with the added weight of tandem rigs and riders. We run gravel inserts when running tubeless.