I am really bad with offsets and wheel sizing, and so I need some one to explain, in lame man's terms, the difference between a 6J +11 offset and a 6.5J +17 offset.

Please, and thank you in advance.

 

Welp the + or - number is how many Millimeters it is off center. If it's +10 ther it will sit 10 mm closer to the axle. the 6j and 6.5j you speak of is most likely the rim width. Either of those you lister should fit, but you might need to roll just the lip of your fenders. Mazda used a +35 offset and 6" rim on the SE. So you can judge by that. I have 7" rims with a +7 offset and they stick out just a little too far. but they're fine on the inside. It's mostly cause I run 225's in the rear. with 205's or 195's they wouldn't rub at all.

 

Offset is based on a perfect center line along the wheel width, 0 offset is that line, poisitive or + offset is millimeters away from the centerline and away from the center line of the car, causing more of the rim to sit inside the wheel well as the hub face is closer to the outside face of the rim.

Negative offset is the opposite creating a deeper dished look.

When working out a rim placement, I do a drawing of a cutaway of the rim, write down the width, halve it to gain 0 point, then add the offset as required, makes it simpler when you see it in front of you.

The easier way, but not regularly used, is to measure backspacing from the hub face to the inside edge of the rim.