brettb

Okay so I'm looking at buying a set of rims for my 74' Olds 98. The problem I'm encountering is the hub is about 3-1/4in in diameter and protrudes about 3in out from the rotor and also has a wider base at the rotor than at the end of the hub. What do I need to do to be able to put custom or aftermarket wheels on? And mount up like factory wheels? Do I need new spindles or a new rotor? Please help. Thanks

brown7373

I twould be a lot easier and less expensive to buy wheels that fit, rather than to re-engineer your brakes.

joe_padavano

If you get lug-centric aftermarket wheels, the center bore will be much larger than the pilot on the hub.

copper128

A 74 Ninety Eight has a standard GM full size hub & rotor. There's nothing about it that requires a "special" wheel.

brettb

Copper128 I'm not looking for a special wheel. LOL just aftermarket rims. Something to fill in the wheel wells. And I'm having trouble finding a rim that will sit all the way on the hub against my rotor. Most wheels I've tried won't meet the rotor or the hub is to big That's why im asking...and the hub on the C-Body GM cars is bigger than that of the impala or the 2nd gen monte carlos. I have both those cars as well amd the olds has a bigger hub...and thanks Joe I'll try lugcentric out and see what they have to offer

copper128

No, the hub is the same as 71-76 Impala or any other GM B/C-body of that time. The Monte Carlo is a G-body, which is an intermediate like the A-body and uses the 4.75" bolt circle.
All B & C-body cars from '71 to '76 used the same 5.00" bolt circle as the 1/2-ton Chevy/GMC pickups, so if you're having trouble picking out a wheel, try specifying one for a '70's era Chevy p/u with 5x5" bolt pattern.

brettb

Well thanks copper that's what I needed to hear. I DONT like the thought of using wheel spacers. So I want something that will fit perfectly. I will try a 5x5truck wheel then. I never thought of that. I know my 76 Monte is a G Body. But it also has large diameter hubs. Being 3inches. I bought Iroc wheels for it and couldn't get them to mount because of the same problem the hub on the wheel was to small for the hub at the base of the rotor.

joe_padavano

I don't know what you mean by "large diameter hubs" but your Monte uses the 5 x 4.75" bolt circle. Those wheels will NEVER fit a car with a 5 x 5" bolt circle. You don't need "truck" wheels, you just need wheels with the correct bolt circle. Note that all 1991-96 Caprices and Impala SSs used the 5 x 5" bolt circle. There are LOTS of aftermarket wheels that fit this car.

brettb

The spindle with the dust cap on it is what I am referring to when I say. Hub. Since it come thru the rotor. That is the only reason why I couldn't get the Irocs on my Monte Carlo. Not because of the bolt pattern the bolt pattern was fine. So are you telling me I should look for rims that fit those 91-96 caprices and SS Impalas? Because you said they're 5 on 5 but I've seen people put Iroc rims on them. And unless I swap spindles and rotors on my Monte and olds. I won't get those to fit. I have front disc brakes. Maybe I should take a picture for you so you can see my problem with the spindle

MDchanic

I have never heard of anyone having this problem before either, so I'm a bit stumped.

5" lug GM wheels are an exceptionally generic pattern.

- Eric

cfhcar

the big hole in center of the wheel is different size late model smaller, i had chevy van rally van wheel on 84 custom crusier fit good. put same wheel on 71 delta 88 they were theigh on center hole were you need a hammer to get them off.

brettb

That's exactly my problem it isn't the bolt pattern its the size of the bore on the hub of the wheel that's keeping me from mounting rims on.

orange442

Your 76 Monte is actually an A-body. GM used A-body for GM intermediates(Monte, Cutlass, etc.) up to and including the 1980 models. After that GM changed to G-body mostly because the standard to metric complete changeover. All 78 and up are usually considered and referred to as G-bodies because of their basic frame dimensions being the same but that is not how GM originally classified them.

My dad has a 1971 Impala with aftermarket Chevy rally wheels in the 5x5bolt pattern and the center bore fit fine. You need to make sure any aftermarket wheel has the correct center bore before you order them. Most if not all should have that measurement available before you order them.

Olds64

Under NO circumstances would I suggest using a bolt patter adapter or spacer. My father (Oldsguy) used bolt pattern adapters on his 69 Delta 88 to install SS wheels. While the car looked KILLER, one of the bolt pattern adpaters worked loose and the rim fell off while driving. Luckily he was only going about 30 mph and nobody was hurt and there was only minor damage to the car.

FWIW, I know exactly what you're talking about Brett. I had the same concerns when I bought aftermarket wheels for my 71 98. As others have said, the 71-76 B/C body cars have a 5X5" bolt pattern.

When I measured my stock wheels before purchasing an aftermarket wheel I got 15" x 7" with a 0mm offset and 4" backspacing. These are the wheels I ended up buying:

http://www.summitracing.com/parts/ae...5750/overview/

I wanted to buy the cragar Soft 8s. However, when I called Cragar to get technical data the representative was rude. So, I ordered the Eagle Alloys instead.

As Orange said you need to make sure the center bore is large enough to fit your brake hub. You also have to make sure the inside depth of the wheel center cap is deep enough to clear the cap on your spindle. Get this measurement by measuring the "height" of the cap on your spindle off of the wheel mounting surface.

joe_padavano

The "metric changeover" had nothing to do with the designation change - which actually happened in the 1982 model year, not 1981. The reason for the shift from "A" to "G" is because the FWD A-body cars (Cutlass Ciera, Pontiac 6000, etc) were released in the 1982 model year. These were supposed to completely replace the RWD A-body line, however GM got cold feet at making such a radical change and continued to produce the RWD cars, changing the designation to "G-body".

brettb

Does anyone know the hub bore measurements on my 1974 Oldsmobile? So I can find the right wheels that will bolt right up

Olds64

Brett, I believe the hub bore is just over 3 inches. I measured this by wrapping a string around the hub and marking it. By measuring the circumference I was able to find the hub diameter using C=2(pi)r.