Originally Posted by andymac

These rims are most likely too wide for a 25 tire. By putting the 700 * 25 on this wide rim you end up with a very low profile tire as the sidewalls are spread out more than they were intended to be. As the sidewalls move out the profile is reduced, the lower the sidewall is the more likely you are to compress the sidewall enough to pinch the tube. This also increases the chances that the rim is actually going to be dented by whatever obstacle it is that you are running over.