Wheel Width Variation

I have four 15x7 rally rims from the 1980s, all of which are in pretty good shape. They all have the same rim code--011 (or 51011)--but one of them is maybe 3/16" wider than the other three. Does anyone know what would account for this difference, or whether this is normal variation? Also, will it make any difference when I get them mounted? I am going to run 255/70 in the rear and 235/70 in the front. Thanks.

 

Are these 5 x 5 "Big GM bolt circle" rims?
They all should have the same width if the have the same code

If I were you, I would mount the wider rim on the rear axle so the "extra weight" will not effect the steering.

7 inches = 177.8 mm
7 3/16 inches = 182.5 mm

A 255 tyre = 255 mm wide, so with the 7 inches rim the tyre will stick out 77.2 mm, that's 38.6 mm on each side.
With the 7 3/16 inches wide rim, the tyre will stick out 72.5 mm, that's 36.2 mm on each size.

The difference of rubber sticking out on each side is only 2.4 mm.
That's 0.09 inch.

Visually you will not even notice that, especially because they are not both mounted on the same side of the car, and the front wheels have a different tyre width.

 

Are you measuring the outside of the lip or from bead seat to bead seat? Bead seat measurement is pretty difficult to get accurately since it's a radius. Tolerance on the bead seat measurement is pretty tight. Tolerance on the lip is pretty loose since it doesn't really matter. Prob. ±⅛".

Regardless, 3/16" won't have much, if any effect but all things equal if it's in the bead seat I'd put it on the LF. However I'd also run them on machine that measures lateral force too (i.e. "pull") & go from there.

You're close. If you want a perfectly smooth ride, PM me.

 

If he lays them flat on the floor, and one of them is higher (width of the rim), that's where he's measuring the 3/16"

 

That could still be the flange or bead seat causing the diff.

 

Hi guys. Thanks very much for the responses and sorry for the late reply. I am measuring lip to lip. Like Nailhead said, I am laying them flat (on a table) and measuring from the table to the top of the rim, and one of them is higher/wider than the other three. I was planning on putting the wider one in the rear, because the rear tires are wider. Does that make sense? Thanks again.

 

PS I got that wheel chart a couple of years ago, which is how I knew they all had the right rim code. And yes, it is five bolts on a 5 inch circle.

 

Like I said before:

 

Yup, thanks.