John Zicha
PCS Member / EMT / PARAMEDIC
We are in search of front and rear rim/wheels for our 1970 Caddy. The ones on it now were put on just to move it around.
Page 7 or 8 of the PDF I put up clearly shows ALL Caddy including 9 passenger limo leaving the factory on the same Kelsey Hayes wheel. Only difference is the 9 passenger left on a larger tire.
I seriously doubt any coach manufacturer had a rim plant.
I'll also go as far as saying possibly a Coach builder MIGHT have put a COMMERCIAL 15" tire on a COMMERCIAL 15" rim as a price adder. If they did they put that tire on a Kelsey Hayes rim.
Commercial rims have a thicker dish and 3 or 4 rivets securing each spoke to the wheel. Wheels were shrunk onto the dish when they were made, trued and then riveted.
A standard 15" tire such as LR78-15 of that time frame will not mount on a COMMERCIAL 15" rim, and a COMMERCIAL 15" tire will not mount on a 15" passenger rim.
This is not to be confused with Chrysler product. Chrysler offered an optional Police/Taxi Service wheel & tire package. Chrysler factory wheels had a lighter dish. I don't recall if Chrysler P/T rims were riveted or welded, but I know where to find 6 of them if I need to check. Chrysler also offered a P/T service rear end and suspension option in that time.
Page 7 or 8 of the PDF I put up clearly shows ALL Caddy including 9 passenger limo leaving the factory on the same Kelsey Hayes wheel. Only difference is the 9 passenger left on a larger tire.
I seriously doubt any coach manufacturer had a rim plant.
I'll also go as far as saying possibly a Coach builder MIGHT have put a COMMERCIAL 15" tire on a COMMERCIAL 15" rim as a price adder. If they did they put that tire on a Kelsey Hayes rim.
Commercial rims have a thicker dish and 3 or 4 rivets securing each spoke to the wheel. Wheels were shrunk onto the dish when they were made, trued and then riveted.
A standard 15" tire such as LR78-15 of that time frame will not mount on a COMMERCIAL 15" rim, and a COMMERCIAL 15" tire will not mount on a 15" passenger rim.
This is not to be confused with Chrysler product. Chrysler offered an optional Police/Taxi Service wheel & tire package. Chrysler factory wheels had a lighter dish. I don't recall if Chrysler P/T rims were riveted or welded, but I know where to find 6 of them if I need to check. Chrysler also offered a P/T service rear end and suspension option in that time.
Walt at Scanlon Tire explained very meticulously that the wonderful folks at GM were putting car wheels and tires on the pickups. He sat one of my tires next to a 15" COMMERCIAL 670-15 and showed me the differences, including weight of the tire.
Paul, we gonna have us a fist fight on this.
I see no reason to resort to violent behavior just because I don't agree with you. Possibly that is how you reconcile your differences with others, but it isn't the way that I deal with people. I deal with reasonable people reasonably, and unreasonable people, not at all. Thank you for advising me that you choose to be unreasonable.
In 1964 I had a half ton Cheby pickup on standard wheels and tires that could devour a set of rear tires in 4000 miles due to the Positraction rear end. I was NOT a happy camper with this situation.
Sorry, I don't recognize the brand "Cheby", however, I do recognize the brand Chevy. If your car 1/2 ton pickup could devour a set of tires in 4000 miles, and you recognize the problem as being the Positraction rear axle gear set, then why didn't you have the differential serviced by the selling dealership? The truck came with a warranty, with a minimum of 12,000 mile and 12 month, or a 24,000 mile and 24 month warrantee, depending on the exact date of manufacture.
One also has to consider the type of tire that was delivered with the truck. In 1964, tires were not known to get high mileage use, and it was common to replace OEM (original equipment manufacture) tires after 12,000 miles. If the truck was being driven by a 19 year old that had to be the first one away from the traffic light, and the first one to the next traffic light, it is very conceivable that the tires would be worn out in 4,000 miles. Tire longevity is all about how the vehicle is driven, both then and now. Another thing that will also effect the tire wear, because of how it is driven, is the differential ratio. Positraction was usually mated to 3.89 gear sets, which made for a very quick "off the line" performance. You didn't mention the engine that your truck had, however, it would have been extremely rare to have a Positraction differential mated up with a 6 cylinder engine.
Walt at Scanlon Tire explained very meticulously that the wonderful folks at GM were putting car wheels and tires on the pickups. He sat one of my tires next to a 15" COMMERCIAL 670-15 and showed me the differences, including weight of the tire.
The original standard tire on a C 15 model 1/2 ton pick up, was a 6.70 x 15 4 ply tire, and the optional tire was a 7.10 x 15 4 ply tire. The next size up from that, is a 7 x 17.5 commercial wheel and tire, that wouldn't fit the wheel studs on a 1/2 ton pick up, since it was for a much higher GVW (gross vehicle weight) truck.
There is a considerable difference in weight between a 4 ply tire, and a 6 ply tire, and even more, if it is a 8 ply tire. As you add ply's to a tire, the circumference of the tire will change to accommodate the additional ply's.
Fine, put the COMMERCIALS on the truck, and I'll swallow hard at the counter when I pay. WRONG says Walt, COMMERCIAL tire will not mount on a passenger car rim. Being a smart young punk, I look at the numbers on both casings and mention they both say 15. Walt handed me a ruler. COMMERCIAL 15" tires have about ½ inch more hole in the middle. They also will not seal on a standard 15" passenger car wheel. A 15" COMMERCIAL tire will not seal on a car wheel either.
Is it possible that in the intervening 42 years, that your memory has faded, and that what you actually were measuring was the 17.5 tire that came on the greater GVW trucks?
The 2 rims I bought for the rear end of that truck set me back $45, 1965 dollars. I also got a hell of a lot more service miles out of the COMMERCIAL casings and had them retreaded twice. It was a damn expensive lesson in 65, and I still remember it.
It is my speculation that the reason that you purchased new rims, was because what Walt sold you were a larger width tire that required a wider width rim, such as a 8.50 x 15 tire.
I learned a lot more lessons from Walt as time went on, some expensive and some free of charge. What back I have left is in some part due to Walt teaching me how to pick a wheel & tire up rather than doing it my way.
When tire measurements switched to letters & numbers from numbers only the wheel diameter number is the same diameter as a passenger car wheel.
I will continue to stay with the position GM half ton pickups and vans left the factory with passenger car sized tires for a long time into the 70s. 3/4 ton and up were floating axles and either 6 0r 8 bolt rims depending on the axle.
3/4 & 1 ton wheels are also hub weight bearing, not wheel bolt weight bearing.
GM, Ford & Dodge bolt holes will line up on 3/4 ton and 1 ton but the center holes are different diameters.
Please note my comments in red below
The statement that I have highlighted above, is absolutely incorrect. Any 15" tire will mount on any 15" rim, provided that the width of the tire is within the tire manufacturers recommendation concerning the width of the rim. The only "commercial 15" tire" that I have any knowledge of was a tire that was supplied to the Cadillac Division for specific use on ambulance chassis. That tire was labeled on the side wall of the tire, "AMBULANCE SERVICE".
I have one of these ambulance service tires. I have many 15' cc rims. No idea how to ship them tho.