[ragcat]

What would you say the correct backspacing on this wheel is? 3 3/4" or just under 3 1/2" or?
Thanks
Chuck

 

[Jan Ove]

Are you sure that the starting point of your measuretape has the same level as the mounting surface on the wheel toward the hub/drum ?
If that point is on the same level, then the backspacing seems to be 3 1/4"
The most correct way to measure the backspace is to lay a straightedge or something similar across the wheel, then measure from the mountingsurface, not completely out on the outer tip on the wheel lip, but as close to the inside of where the tire sits at towards the outer wheel lip.
This site has a great sketching of how to measure backspace correctly, http://www.kodiakracingwheels.com/kodiak spec sheet.pdf

 

[Jan Ove]

And here is another great site that explains how to on wheel measurements https://www.rsracing.com/tech-wheel.html

 

[1969XR7Vert]

What Jan said.

 

[Old man]

According to the Summit Racing catalog, the backspace is measured from the mounting pad to the back of the rim flange. That means the backspace in the photo is 3-3/4 inchs. I guess the correct answer is to go by what your wheel supplier says

 

[Local Hero]

Yep. I always measure to the inner most piece of the wheel with a straightedge across the rim but not the bulge of the tire. I was seeing 3.75 as well.

 

[ragcat]

According to the Summit Racing catalog, the backspace is measured from the mounting pad to the back of the rim flange. That means the backspace in the photo is 3-3/4 inchs. I guess the correct answer is to go by what your wheel supplier says

Actually I'm selling these(http://www.mercurycougar.net/forums/showthread.php?54583-Keystone-wheels-amp-tires). I've posted on CL also and had a couple of folks ask, and just didn't want to mislead anyone. I think I will run one over to the local tire/wheel place though and see what they say. All I know is that I had them on my '73 and they did not stick out the way a really off backspacing would. Front discs poked out a little more than I would of liked, but not horribly so. Was planning on putting them on the '70, but found some others I would rather have instead(Pat's--droptopcat70) .Thanks to all!!
Thanks
Chuck