You should be ok if you keep off the gas. I've seen guys bend control arm mounts on the axle when they run tires that big on a d30 though, so you may want to truss it and reinforce the mounts before you go bigger. Invest money on "prevenative" maintenance, and you'll be glad you did. Just 3 weekends ago, a friend of mine in a tj was running 36's that he borrowed from a friend, and he bent all of his control arm mounts, so it would REALLY be a good idea to reinforce them. I've got pictures of mine if you'd like to get some ideas.