Is this an original tire? Pics...

[KMK454]

Pulled the original spare out yesterday. It had a leather strap on the top. It's a Uniroyal tire. No year marking could be found on it. Is this the OE tire that came with the truck? It looks like it's never been used/touched, and the bolts holding the spare mount had the same light undercoating spray on them that the rest of the underside has.

[tucsonjwt]

Looks like original vintage, but the hub cap marks on the inside of the rim show it has been used on the truck at one time. If you do a google search you can find out some decoding information on tires. You may be able to pinpoint the month/year of manufacture.

[Keith Seymore]

KMK454 - what is this leather strap of which you speak?

I agree with Tucson, btw - hubcap scratches mean it's been installed at some point.

K

[big10ratrod77]

could be my 77 came with uniroyal tires when it was new

[KMK454]

Originally Posted by Keith Seymore

KMK454 - what is this leather strap of which you speak?

I agree with Tucson, btw - hubcap scratches mean it's been installed at some point.

K

Yeah, the tire is ancient but I can't tell if it's original or not. It definitely looks year correct but I didn't think GM sold them with Uniroyals. Maybe the hubcap scratches came from tire rotations. Currently the truck sits on Firestone FR380s and maybe the spare wasn't replaced. The truck only had 18k miles when I bought it in 2007, so that's why I was wondering if this thing was original.

Keith, the leather strap was on the top side of the spare. It was glued to the bottom of the frame and appeared like it was supposed to wrap around the tire like a belt that served as a secondary means of securing the tire. I have no idea if it's original or what. There were two holes that were on the flip side of the adhesive points so maybe at some point it was bolted or tied in somehow.

[Keith Seymore]

Hmm - leather strap is not ringing a bell with me, and the first pit job (underneath) in my area was the spare tire install. I'm wondering if it was just to help protect the tire from rubbing on the frame or the carrier.

Chevy trucks did come with Uniroyal brand tires. Truth be told, there was motivation to supply trucks with the cheapest tire possible, because any savings on one tire was multiplied by 5 (four on the ground + the spare, if it got one; spare was optional).

Here's the link to the info kit for a '78 Chevy pickup from the GM Heritage Center archive. This indicates a G78-15B tire as standard (bias ply).

http://www.gmheritagecenter.com/gm-h...olet-Truck.pdf

K

[KMK454]

Originally Posted by Keith Seymore

Hmm - leather strap is not ringing a bell with me, and the first pit job (underneath) in my area was the spare tire install. I'm wondering if it was just to help protect the tire from rubbing on the frame or the carrier.

Chevy trucks did come with Uniroyal brand tires. Truth be told, there was motivation to supply trucks with the cheapest tire possible, because any savings on one tire was multiplied by 5 (four on the ground + the spare, if it got one; spare was optional).

Here's the link to the info kit for a '78 Chevy pickup from the GM Heritage Center archive. This indicates a G78-15B tire as standard (bias ply).

http://www.gmheritagecenter.com/gm-h...olet-Truck.pdf

K

The leather strap theory makes sense since the two points it was stuck to the frame at were where the tire would have been making contact with the metal. The strap also wasn't long enough to go all the way around the tire, so maybe the original owner put it in there.

As for the tire, it appears to be original based on that document you supplied. Also, I have a 78 Chevy Trucks binder from a now defunct dealership that has all the information on these; I'll check that since it shows specs on everything. I can't believe I didn't think of that earlier...

[Jonboy]

I would have thought they would have been radials by '77, but I could be wrong.

[406 Q-ship]

The 1978 C15 GMC that my Father bought new came on Firestone bias plys and not white walls. Then again back then there were optional tires. I have never seen leather between the frame and the spare but that may have been a dealer fix to keep the tire from squeaking against the frame.

[lurch115]

i'd say there is a good chance its original.

[78 Big10 454]

I've had my 78 since new. It came equipped with G78-15B blackwall Firestones. They lasted all of about 10,000 miles....

[KMK454]

Originally Posted by 78 Big10 454

I've had my 78 since new. It came equipped with G78-15B blackwall Firestones. They lasted all of about 10,000 miles....

Weird; these are G78-15B whitewall Uniroyals. All the documentation I have says G78-15B tires but not what brand.

[Keith Seymore]

Originally Posted by KMK454

Weird; these are G78-15B whitewall Uniroyals. All the documentation I have says G78-15B tires but not what brand.

It won't say what brand. They used multiple brands of tires throughout the model year.

I tried to steer them to put a better tire on my truck when it was built; it didn't work...

K

[Keith Seymore]

Originally Posted by 78 Big10 454

I've had my 78 since new. It came equipped with G78-15B blackwall Firestones. They lasted all of about 10,000 miles....

Uniroyals weren't much better!

(lol)

They would wear funny; they weren't particularly "round" or easy to balance.

For development work - we used to "shave" the tires and do "radial force vector" measurements to try to get a really smooth set of tires

- or -

I would usually keep a set of comparable Michelins, which were better than that right out of the box.

K