I'm not having any trouble with a 30y.o. factory wheel, and I'm 330. Avoid the pot-holes, careful off the curbs, work with the bumps rather than against them, and no mashing.
Serious, don't get your butt out of the saddle unless you want to pringle your wheel or snap your chain (Mr. Frame? Meet Mr. Crotch.) It's OK going up hills, sorta, but from a stop or a slow roll, or into a full sprint, you're asking for it. One of the "advantages" of being big is massive leg strength. Let your muscles, not gravity, supply the torque.
On the other hand, if you're going over a curb or bump, be sure to let your legs take most of your weight... an aware rider makes a better shock absorber than even the priciest component manufacturer.