15x8 Kelsey Hayes Rally Wheel offset

[Seth G.]

I have a set of AZ coded kelsey Hayes wheels with a 5 inch offset. They are NOS dated 1977. The Rallys for my 71 have the correct 4 1/8 offset. Will the 1977 Rallys with the 5 inch offset fit the 71? Thanks!

[Duke W.]

Re: 15x8 Kelsey Hayes Rally Wheel offset

You're confusing offset with "backspacing", which is a rather imprecise measurment because for any given wheel width it varies with the thickness of the tire bead flange.

All OE C3 wheels from '69 to '82 are 8 inches wide and have -0.50" offset. ('68 Rallys are -0.28"; all '67 OE wheels, and previous KOs including the adapters are +0.06"; and previous C2 5.5" steel wheels are +0.44")

Offset can be easily measured with or without a tire mounted.

Place the wheel on the ground on its side, inside facing up, and lay a staight edge, like a section of 2 x 4 across the upper sidewall. Measure the OA width and call this dimension A. Now measure from the straight edge to the wheel mounting plane and call this B.

Offset = A/2 - B, and this will yield the correct algrebaic sign.

Duke

[Joe L.]

Re: 15x8 Kelsey Hayes Rally Wheel offset

I have a set of AZ coded kelsey Hayes wheels with a 5 inch offset. They are NOS dated 1977. The Rallys for my 71 have the correct 4 1/8 offset. Will the 1977 Rallys with the 5 inch offset fit the 71? Thanks!

Seth-----

Being that the 1977 wheels are NOS, they should have a GM part number tag on them. What is the part number?

[Tom D.]

Re: 15x8 Kelsey Hayes Rally Wheel offset

Seth: To answer your question, simply stick one on and look for interference. For example, see how close the lower control arm is to the inside of your rim and tire. If a tire is mounted, put one on the front and see if the tire hits the inner fender when turning. Tire size has a lot to do with the crude suggestions I am giving here...

[Seth G.]

Re: 15x8 Kelsey Hayes Rally Wheel offset

Joe- The part numbers appearing on rim are: X-40317 and HW-81982...thx

[Joe L.]

Re: 15x8 Kelsey Hayes Rally Wheel offset

Joe- The part numbers appearing on rim are: X-40317 and HW-81982...thx

Seth-----

X-40317 = the National Wheel and Rim Association number for the 1969-82 Corvette wheel

HW-81982 = the Hayes Wheel part number for the 1969-82 Corvette steel wheel

So, in addition to the "AZ" code, these identify the wheels as the correct wheels for all 1969-82 Corvette applications. However, if there is no GM part number label on the wheels, then these wheels were not supplied through GM parts channels and, instead, were supplied from non-GM supply channels. No matter, though, they are the exact same wheel except for one thing: wheels supplied through GM parts channels usually have a "GM" stamped into the face of the flange section of the wheel.

[Seth G.]

Re: 15x8 Kelsey Hayes Rally Wheel offset

Thanks! Do you know why this 77 rim is 5 inches deep from the wheel mounting plane vs. the 4 1/8 inches for my 71 rims? The application reads the same 1969-1982 corvettes but that inch difference is a lot. Thanks

[Joe L.]

Re: 15x8 Kelsey Hayes Rally Wheel offset

Thanks! Do you know why this 77 rim is 5 inches deep from the wheel mounting plane vs. the 4 1/8 inches for my 71 rims? The application reads the same 1969-1982 corvettes but that inch difference is a lot. Thanks

Seth-----


Given all of the markings on your wheels, the only way the back-spacing (or offset) could differ from the 69-82 Corvette wheels is if the wheels you have were MODIFIED sometime after Kelsey Hayes manufactured them.