original tire size?
 

Does anyone know what the original tire size for a 71 half ton was?
and what does that translate into in the newer sizes. i would like to know that my speedo is correct. in other words what size tires do i need to buy?
Thanks, Tony

Re: original tire size?
 

It depends on what is listed in the glove box SPID, some trucks came with 16.5 in rims and others came with 15" rims. I know that others will chime in with more info than what I have provided.

Re: original tire size?
 

99% sure it was a 15".

Re: original tire size?
 

Re: original tire size?
 

if im guessing right its about a 28in tall tire which is i think is about a 235/75r15


ive got 31/10.5r15 and my speedo reads 5mph under

Re: original tire size?
 

about the most common factory tire size on halftons was H78X15

Re: original tire size?
 

235/75r15 is the closeesrt you'll get to stock

Re: original tire size?
 

8.25-15

This is the old school sizing. I believe the equivalent is the G78-15. I have the old school tire on the only remaining stock wheel from my truck. I have no idea how old it is, but it's still holding air. Don't know how old the air is, either. Maybe I need to refresh it.

Re: original tire size?
 

According to the resto guide I received from Chevrolet, it is based on GVW.

4400 lbs was a G78-15 bias ply tire.

5400 lbs was a H78-15 bias ply tire or a 6.50-16 bias ply tire.

Any tire shop should have a tire book to convert the old tire sizes to the metric tire sizes.

Hope this helps.

Rich

Re: original tire size?
 

I've got the original sales brochure for my 1972 which I assume would be similar to a 1971. According to the sales information, depending on whether it's 2wd or 4wd, there were 6 tire sizes listed as either standard or optional for the 1/2 ton. The standard tire listed for 2wd 4600 - 5400 GVW and 4wd 5200 - 5600 GVW was a G78-15; the largest optional tire (4wd only) was a 10:00-16.5. There were 4 other optional tires listed as well.

Remember, this was one year newer truck.

Re: original tire size?
 

alot more tire options than i wouldve guessed

Re: original tire size?
 

My '72 has G78-15 on the spare. I was looking on Coker Tire last night and they had a graph on there on bias tire size and radials. So G78-15= 225/70-15 and H78-15= 235/70-15. I'm running 235/75-15 on mine for now.