you get more grip with a wider rim, but i believe that they pinch easier. i run a koxx rim f+r, and ive pinch loads on the rear, with maxxis,luna,monty, with halo, chengshing tubes, at hard and soft pressures.
but ive rimmed out on the front hard enough to put a big dent in it, but no pinch. and its only a monty tyre on the front at about 16psi.
so, when tartybikes gets my rim in, im going back to a 38mm on the rear again.
plus you get more spring with a narrow rim :rolleyes: