I think it's more a matter of maintence/build/riding style than absolute strength. I have 24,32,and 36 hole wheels. I expect to check my 24 hole rims more often than my 36. Having wider tires takes much of the shock out of these but they won't last forever. I suggest picking up Jobst Brandt's book "the Bicycle Wheel" even if you have someone else build/maintain your wheels knowing how they really work is very beneficial. (They don't work like most people assume.)