Looking to upgrade

[Devo88]

I am currently running a 230 series tire on a 15" rim on the rear of my 02 mastiff and i'd like to upgrade to a fat 50 spoke in an 18" rim. is this possible and what tire would i be able to clear with that big of a rim? Im sure this is a pretty basic question but im still pretty new at this.

 

[woodbutcher]

not enough knowledge to give you a good answer, but it also seems like you would have to change the rear sprocket if the overall height of the tire changes. would completely change the output range of the motor. good luck.