here is what i say on that as long as you dont go all out tooo damn big you should be fine. On my 1996 YZF 600r I have a 180/60/17 dunlop sportmaxx tire on the back, so you can go big i think tho that the stock tire width on our particular bikes is a 150 series tire, any other questions just go online and put in http://thundercat.cjb.net this link should be able to answer any questions that you may have, I hope that i have been sufficient enough to offer you help.