David Mau Posted August 21, 2002 Posted August 21, 2002 I am curious as to what the backspacing on the factory 15" x 7" rally wheel was. The ones that are available from various sources today, in both 15" x 7" and 15" x 8" sizes, are typically available in a couple of different backspacing measurements for each size. Thanks! Dave
Mr70Monte Posted August 21, 2002 Posted August 21, 2002 factory 15x7 ralleys were 4" backspacing, the 15x8 Vette ralley is also 4" backspacing.
David Mau Posted August 22, 2002 Author Posted August 22, 2002 They're the same as standard 15" x 7" Cragar S/S wheels, then. Thanks, Mr70Monte! Dave
ejw71 Posted August 22, 2002 Posted August 22, 2002 Just measured both. 15X7 - 4 1/4 and 15X8 Corvette rally - 4. The 15X7 was "said" to be off a '71 Monte. Yep, did it twice. Ed [This message has been edited by ejw71 (edited 08-22-2002).]
David Mau Posted August 22, 2002 Author Posted August 22, 2002 Uh-oh, there appears to be some confusion as to the original amount of backspacing on the factory 15" x 7" rally wheels, then. We have the 4" figure from Mr70Monte. We have the 4 1/4" measurement from Ed. Year One states that the OEM backspacing on these wheels was 4 1/2". I have seen BOTH the 4 1/4" and 4 1/2" measurement listed in The Paddock catalog! Thanks for your help, guys, but unfortunately my confusion still continues! LOL Dave [This message has been edited by David Mau (edited 08-22-2002).]
ejw71 Posted August 22, 2002 Posted August 22, 2002 Correction: The 15X7 is an original 1st Gen. I checked the stamped code. And it measured 4 1/2" back spacing. Ed ------------------ '71 Black 406/700R4 '71 Sandalwood SS454 '71 in process Super Dark Green/346LS1/4L60E
MC-71 Posted August 23, 2002 Posted August 23, 2002 Where are you putting the straight edge to get you mesurement? This might be the 1/2" difference.
ejw71 Posted August 23, 2002 Posted August 23, 2002 I must be go'n blind and/or have lost it. With a straight edge across the inside rim the 15X7 measured 4 1/4" from rim to inside surface of wheel that butts up against the brake drum. I did two wheels twice this time. My advice is not to accept my measurments as correct as evidently I don't have the skill(s) necessary to accomplish the job. Ed
David Mau Posted August 23, 2002 Author Posted August 23, 2002 Good point, Carl. From what I understand, wheel backspacing is measured by placing a straight edge across the back lip of the wheel, running roughly through the center. Then measuring the distance from the backside of the center mounting flange (hub) to the straight edge. If the factory 15" x 7" rally wheels have 4 1/2" backspacing, and the 15" x 8" Corvette rally wheels have 4" backspacing, then the Corvette rally wheels should appear to be 1 1/2" deeper on the OUTSIDE, right? Like I mentioned, my 15" x 7" Cragar S/S wheels have 4" backspacing, so they should appear to be 1/2" deeper (when viewed from the outside of the car) than a 15" x 7" rally wheel, if the rally has 4 1/2" backspacing. I'm trying to visualize where the various rally wheels would fit in contrast to my old Cragars that are currently on the car. Thanks, Dave
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