Tire size question

[65chevysub]

Just out of curiosity, did GM actually put 2cdifferent size tires on the C2500 pickups? Im looking at tires for my 84 Sierra 2500 and it says it had 215/85R16 on the rear and 235/85R16 on the front. My door tag says all 4 were the 235/85R16. Im just curious as to why GM did that?

[cadillac_al]

I have a hard time believing it. Who would buy a vehicle with two different sized tires on it?

[MJN]

Since yours is a 2wd with the C6P suspension package the rear tires were a higher load rating than the fronts, D rated front, E rated rear. All the load was carried on the rear. I think you have the 215 & 235's switched- 215's should be front and 235 rear.
Different sizes were optional front to rear so more info is needed. What does your SPID say? XYJ or XYK for the fronts? Page 41 of this pdf shows:
https://www.gmheritagecenter.com/doc...olet-Truck.pdf

Here is the standard equipment but there are options to put different sizes front to rear as shown on the link above.

[THI]

There were two different GVWR for the 3/4-ton trucks with the heavy Duty being 8600 GVW. The 8600# GVW trucks came with LT235/85R16E tires while the Light Duty versions came with LT215/85R16C - forget if the light duty 3/4-ton is 6600 GVW or 7200 GVW. I do know the RPO C6P would be the 8600# GVW option.

[1976gmc20]

Originally Posted by THI

There were two different GVWR for the 3/4-ton trucks with the heavy Duty being 8600 GVW. The 8600# GVW trucks came with LT235/85R16E tires while the Light Duty versions came with LT215/85R16C - forget if the light duty 3/4-ton is 6600 GVW or 7200 GVW. I do know the RPO C6P would be the 8600# GVW option.

My 1976 apparently came with 16.5" wheels and something like 8.25 (pretty small) bias tires. At least that's what it had on when I got it 20 years later. First thing I did was go to a junk yard and trade out for some 16" wheels and LT245/75r16E used tires.

My 1973 K/20 was 7500 GVW and came with 7.50-16 8 ply tires on split rims. As far as I know, the only difference with the 8600 GVW was that it came with 10 ply. I routinely overloaded it and did manage to blow a couple rear tires But the truck itself was Tough!

[THI]

I should have mentioned my figures above are for the 1980's trucks. My 1978 C20 is 8200 GVW and my K25 is 8400 GVW - both came with 9.50-16.5LT Load Range D tires.