Pontiac Rallys on c1500?

[someotherguy]

A 9/16" drill is .5625 and 14mm is .5511 so if you reamed out the holes with a 9/16 drill you should be good to go. Is the center hole in the Pontiac wheels big enough?

I'm thinking pretty much all that stuff is 78.3mm hub bore so he should be OK. I've seen a few references to 78.1mm but I think that slight of a variation might be an error.

Richard

 

[barelyidle]

Big Pontiac, say for a late 70s bonneville hub measure is 78.3 & 5 on 5, so a set of those based on specs should work. One thing that raises the question about hub bore is some repop center caps I find measure 72 and change so question is when shopping for a set of these does the hub size vary on any 5x5 Pontiac rims or are they all the same meaning the focus is all about 5x5 when browsing the classifieds. does the rim shape itself accommodate the wider hub down below then just become narrower where it meets the cap?

 

[Jimmy D]

Then there is the question of drum brake wheels or disc brake wheels. It makes a difference.

 

[GoToGuy]

It wasn't sarcasm, as much as , falling into the " looks about rite ", bear trap.

 

[someotherguy]

Big Pontiac, say for a late 70s bonneville hub measure is 78.3 & 5 on 5, so a set of those based on specs should work. One thing that raises the question about hub bore is some repop center caps I find measure 72 and change so question is when shopping for a set of these does the hub size vary on any 5x5 Pontiac rims or are they all the same meaning the focus is all about 5x5 when browsing the classifieds. does the rim shape itself accommodate the wider hub down below then just become narrower where it meets the cap?

The center caps don't push through the wheel from behind; they fit a smaller hole on the face of the wheel.

Then there is the question of drum brake wheels or disc brake wheels. It makes a difference.

Absolutely. So while the mid 60's design -might- only fit a drum brake, they ran that style of wheel all the way through the 80's IIRC, which would've necessitated a design change around '68 or so when front discs hit. So while we're still operating on "probably" fit, I'd say the odds are in his favor, unless he found some very early vintage wheels. Excellent point, though.

It's too bad OP seems to be in a situation where he can't test fit one. I'd say it would be recommended to at least try. Take a floor jack, lug wrench, and pop a front wheel off and try. Run the lugs down at least snug and then see if it will still spin.

Richard

 

[barelyidle]

Good thinking on all fronts guys, Richard remember the studs!! so we’re hoping those go well & it actually goes on far enough to see with reasonable force. Then we can tell the hub and the clearance. I just say that about trial fit because I’ve bought enough things off marketplace and whatnot to know the buddy selling them got no time for stuff like that. He just stands in his entrance way kinda like do you want them or not…You all been there. Best try and get a good idea before a guy even shows up at his house so thanks for all the input so far. Better equipped now than yesterday already.

Most of the reason I’m inquiring is ive seen them for sale quite a bit mostly 4.75s in 14 and 15 inch, but some 5x5 15s. As mentioned here they were used for quite a while by Pontiac so they’re out there. I just passed on a set last week because they were 15x6 an inch too narrow for my liking. Which was probably wise, because I’m still wondering if the hub diameter varied on any over the years. Kind of wish I would have went to measure one of those before they sold.

My thinking from the start was theoretically they should probably fit. But when you search c1500s with Pontiac rims in the ol’ google machine you get nothing. If you search the riv ones you get pics and info. So I’m still kind of wondering to be honest. Do they not work? Lord knows I cant possibly be the first a$$hole to try and do this could I?

 

[Jimmy D]

Well if you do try one and it works, you can then be the 1st to claim to have done it.

 

[barelyidle]

Haha I find it unlikely

 

[454C2500Longbed]

Haha I find it unlikely

It could go one of two ways: You ream out the stud holes and they go on beautifully, Or they go on great until the inside of the rim hits the caliper. Found that out the hard way recently, trying to put 14" Keystones on my 68 LTD. 14s do not like disc brakes apparently.

 

[barelyidle]

Yeah isn’t that the truth, I’m hoping clearance is the least of the concerns keeping it at a 15” not going down in size. But never know. Something seems suspicious that no one’s done this before.