13 replies to this topic

[RallyRed]

Hi,
Looked high and low, can't find the PCD info for Chrysler/ Valiant KA/ KB Centura.
Thus....are they the same as LC/ LJ?.
Thanks in advance

[yel327]

I've always thought that Centura were the same as other Valiant/Chrysler and Ford. ie 5 x 4.5". I think Centura used the same studs as Holden though ie 7/16".

[RallyRed]

So, going by this - no match. Ta
‐---------------
The official GM-H figure for Torana PCD (except HB/LC/LJ/TA 4 cyl) is 4.24 ", not 4.25".

Dr Terry.

[claysummers]

And earlier valiant was 4.00”. I got sold a pair of old mags purported to be early Holden/ Torana. Turned out to be 4”x5 stud and had to on sell them.

When I have previously pointed out the 4.24” spec as published in the early workshop manuals, I’ve been shouted down, saying it was a mis-print.


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[Dr Terry]

And earlier valiant was 4.00”. I got sold a pair of old mags purported to be early Holden/ Torana. Turned out to be 4”x5 stud and had to on sell them.

When I have previously pointed out the 4.24” spec as published in the early workshop manuals, I’ve been shouted down, saying it was a mis-print.


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It's not just the "early workshop manuals", it's all the Holden publications. If it was a misprint then they've copied that same misprint many 100s of times since over the last 60-70 years.

 

Also the early Centura had a 4-cyl version which had a 4-stud wheel pattern. Early Valiants (pre-VH) had a 4.0" 5-stud pattern & left-hand threaded studs on the LH side of the car !

 

Later Valiants (4.5" pattern) used 7/16" UNF studs, same as Holden (Pre-Commodore).

 

Dr Terry

[RallyRed]

Thanks gents, saved me buying a set of rims that would not have fitted.

[Heath]

Swap your car to 4.5" P.C.D. like mine and enjoy being able to fit basically any wheel style worth looking at.

[yel327]

It's not just the "early workshop manuals", it's all the Holden publications. If it was a misprint then they've copied that same misprint many 100s of times since over the last 60-70 years.

 

Also the early Centura had a 4-cyl version which had a 4-stud wheel pattern. Early Valiants (pre-VH) had a 4.0" 5-stud pattern & left-hand threaded studs on the LH side of the car !

 

Later Valiants (4.5" pattern) used 7/16" UNF studs, same as Holden (Pre-Commodore).

 

Dr Terry

 

 

I still say it's a mis-measurement or misprint and it's been perpetuated. Although I do know someone that I trust that has measured it and says its close. Reason I say that is what measurement is 0.24"? It is somewhere between 61/256" (0.2383") and 31/128"  (0.2422"). The closest I can get without going to a 4-digit denominator is 123/512" which is 0.2402". Why the hell would GMH design/plan to make a totally unique 4 123/512" PCD stud pattern or for that matter one of the other two either side of it I already mentioned?

 

Was it the imported Valiants (or at least CKD) Terry that had the left-hand threads? 

[RallyRed]

Swap your car to 4.5" P.C.D. like mine and enjoy being able to fit basically any wheel style worth looking at.

Ta mate, it was just about a set of Centura wheels I saw, that I was going to ask if they were for sale.
I already have too many Torana wheels! lol

[claysummers]

You’ve rekindled a debate Col. It is just the kind of geek shit I love. Byron authoritatively asserted it was a misprint, and I am sympathetic to his logic. However US engineers work in thousands of an inch, not fractions? The books all say:
4 24/100”.




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[Bigfella237]

~ Was it the imported Valiants (or at least CKD) Terry that had the left-hand threads? 

AFAIK, it was all Aussie Valiants up to and including VG (no idea about overseas models but I'd hazard a guess that the idea came from the States).

 

As Dr Terry said, the VH was the first to use right-hand-threaded wheel studs on both sides of the car.

[claysummers]

Oh, and Dr. Terry. Say no more….


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[yel327]

I can see both sides of the coin Clay. I have been informed in the past that it is an old error or similar that has been perpetuated, logically also why 4.24” not 4.25”? The whole aftermarket industry has always made wheels as 4.25” as far as I know too.
The other side is why did they never correct it? There are other examples of errors or inconsistencies in GMH Engineering for example HK track measurements, wheel spacer thicknesses etc, mostly caused by rounding of imperial fractions. They sorted that with HT and HG. Also as I said above, I know someone who measured it as accurately as possible that knows what they are doing by measuring between the studs and using geometry to spit out the PCD. They reckon it’s closer to 4.24”. The difference between 2.24 and 4.25” is 0.254mm though which is easy to lose/gain with a measurement and then calculation so there is still some doubt.

Note I corrected this. Damn auto correct changed WHOLE to WOKE. At the end of the first paragraph, it read THE WOKE AFTERMARKET…

Edited by yel327, 07 May 2024 - 08:05 PM.

[claysummers]

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