Im looking into getting 305's out back, but will these tires fit my 9.5 inch rim? How much BFH'ing is needed? its for 18 inch zr1's

 

What specific 305/35-18 tire are you considering? I couldn't find that size on Tire Rack or Mickey Thompson. A 295 requires at least a 10.0" wide wheel, so a 305 may require a 10.5" wide wheel. The Nitto 305/35-18 Drag Radial requires at least a 10.0" wide wheel. But Nittos seem to be much narrower than their sizes would indicate, so you might be able to put that tire on a 9.5" wide wheel.

You shouldn't have much hammering to do if you squeeze it onto a 9.5" wide wheel, since that will pull the sidewalls in. Whether you need hammering will be determined more by the offset of the wheels, than by the width of the tires.

 

I am looking into getting NITTO 555R's...I have no clue what offset my rims are..I know they are the same front and rear. Is there anyway I can measure it?

http://cgi.ebay.com/ebaymotors/305-3...spagenameZWD1V

 

You could measure the "backspace", and I could tell you the offset based on that. The backspace is measured by putting a straight edge across the rear edges of the wheel, and measuring the distance from the bottom of the straight edge to the face of the hub mounting surface.

Check this post in the Wheels and Tires FAQ, stickied at the top of the forum topic page:

http://web.camaross.com/forums/showp...48&postcount=5

What brand/model are the wheels.... sometimes we can find out based on that.