i posted some pics of wheels that i'm using. there seems to be an ongoing struggle to find just the right wheel & bolt pattern . i tend to be a bit oldschool hotrodder so i made what i had work. i started with a set of proline wheels that i got from Pepboys (Ebay) for $25 each . they are 13 x5.5 with 35 mm offset on the front i'm running 175/50R13 and on the back i'll be getting some 185/80R13 . they will give me 20% more top speed . this truck came with 145/90R10 tires . in the pics you can see that it took about an hour to mark and cut 4 wheels so that the 114.3 mm holes lined up on the 110 mm studs. each hole was cut out 2 mm to the inside. left to do will be to install steel inserts behind the nuts to give them a larger seat . so far they seem to be doing fine . you can get this done at the machine shop, i'm not sure of the cost. ( if you don't want your neighbors to see you standing on your head in the back yard) http://www.minitrucktalk.com/galleries/showphoto.php/photo/344
You will run into trouble operating the 4 wheel drive with different diameter tires on the front and the rear. Not a good idea.