brute force

I just got rid of my 05' brute and got a new 10'. I want to toss some tires on probably some zillas. What is a safe size to run since i dont have anything beefed up yet?

I did the bus fix last night thanks to these forums, I would have never known this was an issue. I wasn't have any problems, but I wanted to do the fix regardless. Pictures below. Anyways, I wanted to know if there was anything else I should check and fix since I have plenty of time to do...