If the stock wheel is 7.5" wide with a BS of 5.5" then an 18x9 with 6" of backspacing will stick out ONE INCH more than stock, right??? Anyone? Please tell me if I'm wrong so I can head back to the drawing board!

 

Yep you got it,took me awhile also,also take into affect if the tire bubbles out too.that will stick out also.. i sent you an email back too.

 

I don't think that is correct. Ok so stock wheel is 7.5 and going to a 9" wheel will make it stick out 3/4" further if you had the same back spacing. But 6" BS is more BS so it will pull the wheel in toward the truck .5" more than the factory wheel so basically you will end up with an extra 1/4" of tire sticking out.

the smaller the BS number = the more it sticks out.

Edit: I could be wrong but hopefully the expert will be here shortly to clarify.

 

9 inch minus 7 .5 is 1.5 then subtract the .5 in back spacing and you have 1 inch.thats the way i measured it,if i did it wrong im sorry.

Nick have you decided on a tire?

 

That 1.5" is split between both sides so it is .75" to each side so minus .5" = .25"

It's like getting a 2" bigger tire - it will only gain you 1" in height.

 

The 1.5" isn't split between both sides. You're forgetting the backspace. The back space tells you how much of the wheel will be on the inside. Going from a 5.5" to a 6" tells you that only .5" of that 1.5" will be on the inside leaving the remaining inch on the outside. If the backspace was the same, then then entire 1.5" would be on the outside. Your tire height is correct because the wheel and tire are vertically centered on the mounting point. The wheel is not horizontally centered.

 

OK kewl. learn something new every day

 

I just read what I wrote and didn't like how I said it even though it made sense. Basically, backspace is the amount of wheel that will be on the inside of mounting surface. To figure out how much farther the new wheel will stick out past the old wheel, you have to know both backspacings and then do the math. Take the width of the wheel and subtract the backspace to find out how much will stick out past the mounting surface. Do that for both wheels and then subtract the difference for your answer. This is only part of the equation though as the width of the tire will also matter because certain tires bubble out past the wheel farther than other tires like pat said. It's enough to drive you insane when looking for the right wheel. They're too damn expensive to not do right the first time. I've actually sat down adn drawn it out when trying to figure out how it all worked. And still didn't understand it even after that.

 

As long as nick knows whats right so he can figure out what he wants

 

yes esf your second description is mor complicated but your first description is correct as well and easier to understand. it is actually pretty easy to understand wnce you figure it out.

it is best to just think of the backspacing as the distance from the mounting surface to the inside wheel. that said, means bigger backspacing means rim is tucked further back in. so a rim 1.5 inches wider than stock would stick out 1.5 inches if the backspacing was the same as the stock 5.5. but with .5 inches more backspacing it will stick out only 1 inch further than stock.

perhaps we just described the same thing in differant words but that is the simplest way I remembered it. now try to figure out offsets and I understand it but it can be quite confusing to figure out. I will stick with backspacing. that is simple to understand once you figure it out.

 

Haha. It's real simple to understand when you already understand it. I can try again but it won't sound any less complicated.