Expain to me the diff of JJ and HW codes - Pontiac GTO Forum
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post #1 of 4 (permalink) Old 06-27-2016, 12:28 AM Thread Starter
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Expain to me the diff of JJ and HW codes

I was told to find a set of 15 x 7 JJ rally II rims, so far no luck but I keep seeing HW coded rims. Now what is the difference in these two rims? Main concern is offset...since I'm putting on a 67 that didn't have 15" tires anyway. Thanks for your input, Bryan
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post #2 of 4 (permalink) Old 06-27-2016, 09:50 AM
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American oem steel wheels and steel wheels from the 60's-80's will have the size 13x5, 14x5, 15x6, 15x7, etc, followed by JJ or JK stamped inside on the spine of the wheel. The two letters JJ or JK are a reference to the standardized outer wheel lip design by the ASAE, American Society of Automotive Engineers. Those two letter codes right after the the size, typically, are NOT used to identify the wheel.

On Pontiac factory usage rally II wheels the two letter code stamped to the right hand of the valve stem identifies the original use of the wheel. (Some early JC coded rallyII's were stamped on the lh side of the valvestem). There are 34 of these specific 2 letter rally II ID codes. Wallace Racing site has a link with pics of various styles of date coding of original rally II wheels and how to decode the date the wheel was produced. Need to identify a specific 2 letter wheel code APPLiCATION, feel free & drop me a PM.

In the case of the oem 15x7 4 3/4" bolt pattern Rally II's, the most common are the HM and the HW. HM's could be ordered on '73-75 GrandPrixs, LeMans, '73 GTO's, Formula's and T/A's. The HW coded 15x7 followed in aprox '76 and was avail after '76 on TransAms & Formulas through the '81 model year. Both the HM and HW wheel will interchange. Typically, only hardcore '73 and '74 T/A restorers are interested in buying or piecing together date code matching sets of HM's.

Hope this helps shed light on these wheels and how to properly ID them.
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post #3 of 4 (permalink) Old 09-07-2016, 05:54 PM Thread Starter
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I now understand, thanks.
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post #4 of 4 (permalink) Old 10-01-2019, 12:34 PM
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I ran across this thread and was curious how you made out. I have a 69 GTO and have a line to get some Rally II wheels wtih HW code. They are restored and I know they will fit but concerned about getting the right trim rings and center caps that have the PMD logo correct for 69. I now reproductions are out there but want to confirm they will fit the HW coded rims.
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  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO Wheels & Tires

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