Originally Posted by Russ Roth

I find this conversation to be very informative as I'd always assumed that 100psi is a 100psi and if that's what a rim is rated for than why would the tire matter. Still not fully getting it as the amount of material in contact with the rim would seem to be the same regardless of the tire size, either way its the same amount of tire contact at the bead as well as the same amount of pressure contained within the system, So is it ultimately a leverage situation? The way the tire expands pushes out on the rim differently effecting how the stress of holding the tire is placed on the rim? Cause I read the amount of area being an issue but I don't see how a larger tire has any more area in contact with the rim. The larger tire has a larger cross section obviously but it would seem to me that there can't be any additional amount air in contact with the rim as the bigger tire does nothing to change the amount of surface area of the rim the tire/tube/air can act upon. How can any size tire with a 100psi apply more pressure than 100psi onto the rim other than by increasing the load on the tire?