Hey all. Been ready the fourm for a few weeks now. Bought a new bike last week. It was a hard choose between at 16 grizzly or a 2015 800r xt. I am Coming off a 2012 arctic cat 450. Well got the 800 and wow. These things do have power. Rides awesome very happy with decisions. So the question everyone asks. Tires. It will be zilla or mayhem Not sure on size 27-28. if I go 28 mayhem is there a big power loss. First time having this much power and don’t want to give any up. Will 28 fit without wheel spacers. I am using stock rims. Do you need a clutch kit. Some people say you have to trim some people say you don’t. Thanks in advance