The term "reversed wheel" has kind of taken on a life of it's own. Originally a reversed wheel was called that because the center of the wheel was actually reversed inside the hoop, giving what is technically a negative offset. Now it's kind of a blanket name for any "deep" wheel. Kind of like Xerox?

On Ford and Mercury wheels (and probably most makes) of the 40's (and I think early 50's) the centers were riveted to the hoop. If you were to drill all but two opposing rivets you could literally spin the center inside of the wheel without removing it, then weld up all of the rivet holes. Basically, although the center stayed in the same location when bolted to the hub, the hoop and tire moved toward the outside of the car.

I know that doesn't answer your question, BUT the difference between a 3-3/4" and 4" of backspacing is 1/4", right? Just measure from the inside lip of the wheel 1/4" toward the inside of the vehicle and make sure nothing interferes. The new wheels with 4" backspacing will move your wheels IN 1/4". This may or may not be what you're looking for... things like fender lip clearance come to mind here.

There are two other important things to consider when measuring here too! First, remember that the innermost edge of the rim moved toward the center, and so did your tire. Check steering lock-to-lock and make sure that you don't have the inner sidewall rubbing either. A 1/4" can make a big difference when magnified by steering angles. Second, if you're replacing a wheel with more or less backspacing but the same width, remember that you are also changing the distance between the outer sidewall and the fender lip.

I probably didn't tell you anything you don't already know... just rambling here, sorry.

Yes you did! But I'd rather listen that talk. Sometimes I go off on a tangent though...

Easy one John... and the only stupid questions are the ones you don't ask.

Offset refers to the amount of space between the inside wheel lip (outermost edge) and the mounting surface of the hub. Zero offset means that the wheel hub is exactly in the center of the front and rear wheel lips.

A reversed wheel typically has very little back space, resulting in what most people used to call a "deep dish" wheel. This is also called "negative backspace".

Positive offset is where the backspace is greater than the distance from the inside lip to the wheel hub, than from the outside lip to the wheel hub. Positive offset is measured from the wheel hub to the outermost edge of the wheel. Positive offset wheels are commonly found on front wheel drive cars.

Negative offset is measured in inches, positive offset is measured in centimeters. Hope this helps. I'll attach a diagram I drew years ago to help a friend.

I love learning! There are a few things that I know well that I try to share, but most of the stuff posted here is a learning experience for me! That's why I read every thread, to learn!

And no, you're not stupid. As long as you're willing to ask and learn you're miles ahead of most people!

Yes and no. Although an 8" rim may have the hub surface mounted in the middle measuring 4", the extreme edges of the center are welded to the hoop in another location. If you were to "reverse" the center you can see how dramatic the change is. The mounting point stayed the same, the hoop stayed the same. Simply flipping the center 180 degrees changes the depth of the wheel substantially.

What used to be the outside portion of the hoop is now toward the inside. Does that clarify it? I'm afraid that I still haven't really answered your question.

Here's a quick diagram. The red line indicates the mounting surface to the axle.

Holy Kow, Eric.

That's got to be the best explanation I have ever seen/heard on this topic.

Somehow I feel smarter just reading this thread........Thanks.-Brant