OE tire & wheel specs for 1977 Dodge D100 pickup?

[Gus Grebo]

I'm trying to figure out what the factory tire size for a 1977 Dodge D100 pickup is.
I'd also like to know what the OE rim width is.

Right now, the truck is sitting on a mix of G78-15 and H78-15 tires. Not sure which, if either, is the correct size.

Different tire websites give me different results for modern conversions. (205/75R15, 235/75R15, 225/70R15... )

This truck is a pretty low-end light-duty example. 225 slant six engine, 3-speed manual on the column, 2WD. VIN indicates GVWR "under 6000 lbs", but the data tag on the truck says GVW is 6100 lbs (???).

The truck doesn't run and is sitting on flat tires. I need to get it roll-able so it can be loaded onto a trailer. The quickest way to do that might be to put the wheels from my 1999 Ford Ranger on it. Same bolt pattern and stud size. However, the center hole on the Ranger wheels is 1.1mm smaller than the Dodge wheels, according to wheel-size.com. The center hole of the Ranger wheels fit fairly snug around the Ranger hub. I'm not sure if the Dodge wheel's center hole fits tightly around the dodge hub, or if there is a bit of a gap. If there's a gap, the Ranger wheels might fit the Dodge.
Does anyone know if there's clearance between the hub and the center hole in the wheel on these old half-ton dodges?

The truck resides about an hour away from me, so I'm trying to figure this stuff out in advance so I don't have to make a trip just to take measurements, or waste a bunch of time removing the wheels from my Ranger and hauling them out there only to find they won't fit.

Thanks!

 

[slacktide_bitog]

Did they have tire labels in the car back then?

According to Coker the Coke Dealer, a 77 D100 2WD could've come with G78-15, H78-15, or L78-15.

How old are those tires if they still have the letter ratings?

Just pick any of the modern sizes, or perhaps consult Chrysler/Dodge/Ram dealer or Chrysler itself or maybe forum about these trucks.

 

[eljefino]

You already got your answer from wheel-size.com, sorry. You often see hub bores consistent across manufacturers but going from Ford to Dodge as you're trying, anything's game. Your Ranger tires will NOT fit.

I'd get a good cordless inflater, the old tires will hold air for 40 feet of dragging. I'd worry more about the drum brakes freezing TBH. But if your winch is powerful enough, you're going to get that truck home.

I wouldn't be surprised if the 6100 GVW is an emissions dodge as trucks had lighter requirements for heavier weights. This is also why the Ford F100 disappeared in the very early 1980s.

 

[CapriRacer]

According to Tire Guides, the OE tire size was either H78-15 or L78-15.

Look in the glove box to see if the vehicle tire placard is there. Back then, placards could be found in a lot of different places and the glove box is the most likely.

You can't get an exact fit with modern tire sizing. If you want to maintain overall diameter, of the H78-15, you need to use 225/75R15, but the wheel width is too narrow, so the tires are going to wear in the center. If you want a better fit, but are willing to accept a smaller diameter 215/75R15.

While there is an equivalent to an L78-15, nothing actually fits the rim width, but a 235/75R15 is close to the same diameter. Again, wear problems.

 

[hemitom]

I believe the closest to stock is 215/75/15.
L rated tire 235/75/15.
we had a 77 royal Monaco wagon wagon it sported L 78 15 when new