need help with wheels HELP

Heres what i have a 94 mazda b2200.I did the ranger 5 bolt change over with the ranger rear axle and redrilled frnt hubs.I have custom built a-arms and mazda drop spindles up front. truck is fully bagged. The rims i have on it now are frnt 18 in x 7.5 with a 40 mm offset and the rears are 20x8.5 with a 45mm offset the rear rims hit the bed sides right were the body line is. I want to keep the same 18 and 20 combo but what kind of offset do i need for the rear. frnt rims fit fine. any help will be great Thanks Joe

heres some more info with the wheels off.. brake drum to the point where i hit is 3 1\4 inches.

so does the rim hit the body line or does the tire?

both would with these rims but the tire hits first the the rims if you go down futher..

Can you measure to see how much further you need the wheel to go in on each side in inches and convert that to mm and add that to the offset?

so if its 45mm right now do i+ or - the number off..How do u tell if its a positive or negitive offset??

The way offset is calculated is by first starting at the center line of the wheel. That would be a 0 offset. If the wheel mounting face is moved closer to the outside edge of the wheel this is positive offset. If the mounting face is moved towards the hub this is negative offset. Since you need more clearance you will be adding the number to your current positive offset wheels increasing the positive offset.

C:\Documents%20and%20Settings\Joe\My%20Documents\My%20Pictures\mazda\SDC10086.JPG

Try rimsntires.com click on the wheel comparer link on the left hand side, plug in your info. you might have to play with it a little but it should tell you what you need to know. Hope this helps.

photo.php?fbid=2091932457292&set=a.2084159022961.128850.1214673801&type=3&theater


Ya i have been playin with that but it says stock for a mazda is a 5 bolt ranger,I have been emailin them thay said to use spacers