Hi from New Zealand,
A wheel and tyre shop down here in Auckland has offered me some 18" alloy wheels for my 1965 Cutlass Sports Coupe.I believe the Cutlass stud pattern is 5x120.65mm (4.75") and the alloys are from a GM Holden Commodores that you may know them as a Pontiac GTO in USA.The stud pattern for the Commodore is 5x120mm (4.724") which is only a slight difference but.... The tyre shop guy said not to worry about the .65mm and just think of needing a 120mm sized wheel but I have just found something about this on another website which says not to use the 120mm size on a 120.65mm sized car because the Cutlass wheel studs may well be damaged and break off!I would appreciate some advice on this before I drive an hour away to check the wheel fit on my car.

 

Don't do it!.


Sounds to me like the tire guy just wants to make a sale.
If the wheels don't fit the stud pattern you will be putting a lateral load on them thay are not designed to deal with.
You may find you will have invalidated your insurance by fitting incorrect parts on a vital safety aspect of your car.


You can have wheels redrilled to the correct pattern in some cases. if not with these wheels then I would pass on this one.


Roger.

 

X2

 

Not only is the bolt pattern wrong, but the offset will also be wrong. Get the correct 5 x 4.75" wheels. This bolt pattern was used on just about every Chevy through the 1990s, so aftermarket wheels in this pattern are common, even in Oz. Also, find a new tire shop that has a clue.

 

X2 on finding a tire shop run by people who know what they are talking about.
Joe, a Kiwi doesn't come from Australia, .
Like me saying you are a Canadian. Now you'll tell me you were born there.
No offense intended.


Roger.

 

Thanks for your input people. I had thought that if you used tapered wheel nuts that would take care of any potential problems but perhaps not.
Last night I talked to a guy in my car club and he has been using 5x120.7 sized rims on his 5x120 Commodore without any problems even while using them for burnout competitions. At the end of the day isn't worth the risk. especially so when I want rims to fit the Hankook 285/40/18 slicks I have to do a bit of 1/4 mile drag racing with my car club.
As far as the Australian thing is concerned some of us Kiwis would be most upset to be called an Aussie but I just laughed when I saw it.
Cheers

 

The wheel studs are still on a different circle diameter than the holes in the wheels. Assuming these are proper hub-centric wheels, then all the tapered lugs and seats will do is impart an additional bending preload on the studs as the nuts seat in the taper. Not the smartest thing to do. If these are lug-centric wheels, then it's an even worse idea.

 

Wait it out find the right rims search craigslist too in the end you'll feel safer and feel better about your decision

 

I've been looking at various wheel related websites and just came across this one http://www.twe-inc.com/applications.php I wonder where they got the 5.00" (127mm) from?

 

Just a typo, 5.00" is roughly 125mm.


Roger.

 

I noticed my bad typing and edited to make a correct 127mm.Thanks Roger
Weird about these guys having 5" listed for F85, Cutlass etc wheel stud pattern

 

That's correct for 1974 or so and later

 

NO, NO, NO.

Every RWD Cutlass/F-85/442/Vista Cruiser from 1964-1988 used the 5 x 4.75" bolt pattern. The 61-63 cars use a 4 x 4.5" pattern.

In my experience, every one of these on-line bolt pattern sites has some error in it.

 

I believe the Cutlass stud pattern is 5x120.65mm (4.75") and the alloys are from a GM Holden Commodores [Pontiac GTO].The stud pattern for the Commodore is 5x120mm (4.724")
==========================
Is there any evidence that the bolt patterns are ACTUALLY 0.65 mm different?
Seems like GM would just use 4.750" [plus or minus 0.005" or so] whether the car was called a Holden or some USA model. This is a 0.026" difference on a 4.750" circle, which you cannot easily measure the diameter of because there are no two studs or holes directly opposite.

If this is a verifiable measurable difference, then, sure, use exact mating parts.

OTOH, if it's just a matter of the nominal reference varying while the actual parts are all the same, then it can make no difference.

 

I'm pretty sure it's a real difference. Keep in mind that the Holden (and now the new Camaro) parts were originally designed in a country that really does use the metric system. Here's the rotor for a 2010 Camaro. 120.0 mm bolt circle doesn't sound like 120.65 mm. And again, even if the bolt circles were compatible, the newer RWD cars still use the large positive offset wheels like FWD cars. Not what you want for an older RWD Olds.