replacement wheel center hole size?

[Colin B.]

I have a stock '63 (drum brakes) with the newer P207 70 R15 tires. I purchased a replacement wheel (for my spare) from a Corvette parts company, but it has a 3 1/8" axle center hole, while my '63 is 2 3/4". Also, my 63' wheel has a small lip around the center hole that come up to meet the axel, while the replacement is flat at the center. The replacement wheel's bolt pattern and fit on the drum is fine, but I am concerned that the extra 1/8'' clearance around both the front and rear axle hubs may be a problem?

Would appreciate advice on why the difference and if it is okay to use it as a spare tire???

thank you, Colin
(51038)

[Terry M.]

Re: replacement wheel center hole size?

Original Chevrolet wheels, I believe even going back farther than 1963, have been hub-centric. That means the wheel is centered by the hub and not the tapered lug nuts. I know for sure my 1967 Chevelle is this way, and I believe other Chevrolet and maybe even all GM products are. I have to confess my 1937 Cadillac is in no condition to check this feature, and it has been apart too long for me to remember.

Will the tapered lug nuts and wheel cones center the wheel? If you are careful installing the wheel -- that is don't put the weight of the car on the tire until the lug nuts are all snugged down -- they likely will, but it is not the way the engineers designed the system. For spare tire (occasional) use it may not be that big a deal, and likely never get noticed in judging.

[Joe L.]

Re: replacement wheel center hole size?

Original Chevrolet wheels, I believe even going back farther than 1963, have been hub-centric. That means the wheel is centered by the hub and not the tapered lug nuts. I know for sure my 1967 Chevelle is this way, and I believe other Chevrolet and maybe even all GM products are. I have to confess my 1937 Cadillac is in no condition to check this feature, and it has been apart too long for me to remember.

Will the tapered lug nuts and wheel cones center the wheel? If you are careful installing the wheel -- that is don't put the weight of the car on the tire until the lug nuts are all snugged down -- they likely will, but it is not the way the engineers designed the system. For spare tire (occasional) use it may not be that big a deal, and likely never get noticed in judging.

Terry and Colin-----


Personally, I would not install a non-hub-centric wheel on a Corvette.

[Jim L.]

Re: replacement wheel center hole size?

All of my Corvettes are '63 and older and all of them center the wheels by the conical lug nuts. The size of the hub hole is irrelevant.

Here are some example pictures:

Front of my '63:




Rear of my '63:



My '54:




So while a wheel with a 3" hub hole might look a little strange, it will work just fine. Use it and don't worry about it.

Brake drums and rotors, on the other hand, ARE hub-centric.

Jim

Edit: Before someone takes me to task for an omission: KO wheels are centered by the conical surfaces of the spinner and the wheel, not the drive pins. The drive pins can be and, in fact, must be a little loose to allow for the wheels to be spinner-centric.

[Terry M.]

Re: replacement wheel center hole size?

All of my Corvettes are '63 and older and all of them center the wheels by the conical lug nuts. The size of the hub hole is irrelevant.

Here are some example pictures:

So while a wheel with a 3" hub hole might look a little strange, it will work just fine. Use it and don't worry about it.

Brake drums and rotors, on the other hand, ARE hub-centric.

Jim

Edit: Before someone takes me to task for an omission: KO wheels are centered by the conical surfaces of the spinner and the wheel, not the drive pins. The drive pins can be and, in fact, must be a little loose to allow for the wheels to be spinner-centric.

Jimj,
Are those OEM wheels? I am just trying to learn.

[Jim L.]

Re: replacement wheel center hole size?

Jimj,
Are those OEM wheels? I am just trying to learn.

Terry, yes, those are the original, factory installed wheels on both of the pictured cars.

Jim

[Gene M.]

Re: replacement wheel center hole size?

The photo with the red wheel looks as if the center hub does not have a turned machine diameter for the rim to set on. Check the diameter of it with calipers.......... May just be the photo but something does not look right.

[Jim L.]

Re: replacement wheel center hole size?

The photo with the red wheel looks as if the center hub does not have a turned machine diameter for the rim to set on. Check the diameter of it with calipers.......... May just be the photo but something does not look right.

All hubs are machined for locating the brake drums and rotors. That machined region extends out from the mounting flange by only a quarter inch or so (varies with hub design). Farther outboard from that machined area the hub is as-forged and tapers slightly for ease of drum and wheel installation.

There is nothing wrong with either the hub or the wheel on my '54.

Think about it this way:

1. Lug nuts are conical as are the lug seats on wheels.

2.Conical shapes are self centering.

3. Any wheel must have only one centering mechanism otherwise tolerance buildup would cause centering conflicts from among the different mechanisms.

To prevent these conflicts, hub holes are designed to be larger than the hubs to allow the self-centering lug nuts to work properly. Hub holes don't have to be significantly larger than the hubs, just larger by a sufficient amount to not interfere.

Jim

[David L.]

Re: replacement wheel center hole size?

Original 63-64 Corvette wheels (GM # 3825686 & 3834127) have a hub hole that measures 2 25/32" in diameter. In August 1965 wheel # 3834127 was replaced with wheel # 3839814 which has a hub hole diameter of 2 29/32". The 3839814 wheel was then replaced in May 1966 with the 3838080 wheel which have a hub hole diameter of 2 25/32". I believe that the 3838080 wheel was original equipment on 1966 Chevrolet Police cars.

BTW, I have never found any difference between the early 3825686 wheel and the 3834127 wheel. Chevrolet Parts History uses the term "MIX". Most part number changes in the Chevrolet Parts History catalog use the term "USE".

Dave

[Joe L.]

Re: replacement wheel center hole size?

All of my Corvettes are '63 and older and all of them center the wheels by the conical lug nuts. The size of the hub hole is irrelevant.

Here are some example pictures:

Front of my '63:




Rear of my '63:



My '54:




So while a wheel with a 3" hub hole might look a little strange, it will work just fine. Use it and don't worry about it.

Brake drums and rotors, on the other hand, ARE hub-centric.

Jim

Edit: Before someone takes me to task for an omission: KO wheels are centered by the conical surfaces of the spinner and the wheel, not the drive pins. The drive pins can be and, in fact, must be a little loose to allow for the wheels to be spinner-centric.

Jim------

A couple of things:

On my 1969 there is no measurable clearance between the wheel center hole and the front or rear hubs. I assume this is the same for at least all 68-82 Corvettes with the possible exception of those later C3 with aluminum wheels. The GM spec for center hole size for all 1963-82 Corvette wheels is 2.783".

Second, for long-in-service wheels and lug nuts, the lug bolt holes enlarge due to wear and the seats narrow considerably due to wear. The lug nuts' tapered seat becomes galled and loses its smooth, tapered "centering" feature. These factors are certainly obvious on my 1969's original wheels and lug nuts. They're also pretty obvious on what I can see of the wheels and nuts in your photos. Of course, the lug nuts can be replaced (although they often are not) but the wheel lug nut holes and lug nut seats can only be corrected by replacing the wheel. So, if the lug nuts and lug bolt holes are what centers the wheel, then there must be a LOT of vehicles out there running around with un-centered wheels. I would think that would make for a very rough ride.

[Terry M.]

Re: replacement wheel center hole size?

I can assure you that my 1970 Corvette has hub-centric wheels on it, and they are the factory wheels.

My 1995 Caprices (Caprici?) -- all three of them -- have hub-centric wheels, but they were all built as police cars and those do have different wheels than standard passenger cars. I know they differ in the strength of the wheel, but I do not believe there is a difference in the wheel center size.

My former 1976 Suburban had hub-centrric wheels.

A former 1978 Caprice also had hub-centric wheels.

As I said in my first post, my 1967 Chevelle original wheels are hub-centric. When I converted it to 4-wheel disk brakes I had to send one of the front rotor/hub assembly back because it was too large for the wheel to fit (.030 as I recall). The current wheels on the Chevelle are cast, and not of Chevrolet manufacture -- American Racing as a matter of fact, and guess what? -- they are hub-centric also.

Both my 2001 Camaro (another former police car) and 2008 Corvette have cast wheels, but I am sure the Corvette wheels are hub-centric, and while I am a little less sure of the Camaro, I believe it is the same. The wheels on the Camaro are the same as the Z28 anyone could purchase.

As I said I can not easily test the 1937 Cadillac -- so I should have posted what I know rather than making broad sweeping statements. Oh, and you may ask how do I know/remember all this? Fair question. Living in the Midwest where it is common for the roads to be salted at certain times of the year, and there are wide temperature swings and the humidity is often high -- any corrosion build up on the hub will freeze the wheel to the hub in short order. Anti-seize rapidly becomes your friend -- either that or a BFH. And yes, that is even for the Corvettes and now the Chevelle that are driven only on unsalted roads. Mother Nature is a b*&%h.

[Jim L.]

Re: replacement wheel center hole size?

Whatever The General decided to do for Corvettes made after 1963 and prior to 1984 I can not say. There may very well have been a conversion to hub-centric wheels.

I have seen C4 hubs, however.

The machined centering pilot on them is barely wider than the thickness of the brake rotor. The wheels that attach to these hubs would have to be centered by the wheel studs like '63 and earlier wheels.

Jim