wheel tech question (offsets)

[Sully]

Im not sure where this thread should go and I know that offset means how far off the center line and in what direction the hub sits. My question is that I dont 110% understand the correlation between width and offset.

If wheel A is 8" with -12 offset and wheel B is 10", the back spacing will change but the offset stays the same? What I am trying to figure out is if I want wheel A but in 10" like wheel B, do I still want a -12 offset or does it change. If it changes how and why please and thank you.

 

[Gary98K1500]

http://www.fullsizechevy.com/forum/...terior-tech/76444-wheel-offset-explained.html

Hope this helps man

 

[jcro61]

The offset will change the backspacing when all things remain the same but the width changes.


It is all pretty simple. That picture on the fsc thread should clear it up easily.

The offset will just allow for a specific rim width to have different back spacing for various fitments.

 

[Swims350]

IMO offset isn't as important as the backspace.

 

[jcro61]

Offset is what will determine what the backspace is.

For example if you have a wheel 10" wide with 0 offset it will have 5" of backspacing. If you had a 10" wide wheel with +25.4( i know its odd number but its easier to show here) than the wheel would have 6" of backspacing. -25.4 offset would render 4" backspace. Hope that helps. So all you need is the wheel width and the offset to figure out what the backspacing is. Sometimes they do not list the backspace just the offset. So offset and backspace are just two ways to measure. One is not more important than the other.

 

[Swims350]

I always buy mine from summit and they list BS on there, but I never had to worry about BS until these freakin trucks and they dished in wheels and crap.

 

[Sully]

grrrrrr.... this is something that boggles my mind for some reason. I am an electronics engineer and yet wheel spacing confuses me.

 

[Toms94z71]

I know you got knew wheels already, but anyone else that might stumble across this thread, here is a good site on wheel tech. https://www.rsracing.com/tech-wheel.html

 

[Mike]

There are usually only 3 options for any wheel that fits on a GMT400. Negative (lowrider) middle (stock or mild lift) positive x9.5 and x10 (big lift). Therefore depending on your application only one wheel will be appropriate.

 

[xtreme.97]

There are usually only 3 options for any wheel that fits on a GMT400. Negative (lowrider) middle (stock or mild lift) positive x9.5 and x10 (big lift). Therefore depending on your application only one wheel will be appropriate.

actually it would be the opposite. not sure on these trucks what works best on a lowered truck, but a negative offset will push the wheel out away from the truck (best for lifted). a positive offset will pull the wheel in towards the truck which would cause all kinds of rubbing issues.

let me see if i can word this correctly to explain. lets say we have a 10" wide wheel. first we look at the center line of the wheel, which in this case would be 5" from the inside lip of the wheel. now we can determine offset which measures where the mounting surface of the wheel is in relation to the center line. if the wheel mounting surface is exactly 5" from the inside lip (right on the center line) then the wheel has a 0 offset. as we move the mounting surface towards the inside lip (which when mounted on the truck will push the tire away from the truck) the offset becomes negative. if we move the mounting surface towards the outer lip (pulling the tire in towards the truck) then the offset becomes positive. so if we have, say for instance, a wheel with a -6 offset, that means the the mounting surface is 6 mm closer to the inside lip of the wheel than the 0 offset wheel. thats why offset and backspacing are related. backspacing measures how far the mounting surface is from the inside lip. the same 0 offset wheel that is 10" wide would have a backspacing of 5". the tricky part is figuring out backspacing using the offset because offset is measure in mm where as backspacing is measured in inches. basically they both measure the same thing, just a different way of measuring. hopefully that helps!!!