Suburban frames 1500 vs 2500

[Roaddogg]

Speaking specifically on suburban frames, does anyone know if there is a difference between the two frames?

[Ski-me]

I don't think there is a difference. It's mainly the running gear that make the 2500 difference.

[Roaddogg]

That's kinda what I was thinking but haven't found anything to say either way. I wonder if on the RPO sticker in the glovebox if it says the chassis used. I believe I've seen this on the trucks

[ericjon262]

I've heard the 3/4 ton frames were the same shape, just thicker metal, I have yet to confirm. if anyone has a 3/4 ton and wants to measure the thickness, I'll measure mine in the same spot and see if there is a difference.

[1976gmc20]

My understanding is that K-10 and K-20 frames were the same, at least back to the early 1970s. I've had some of both though not at the same time, and the frames looked to be same thickness. I don't recall if I ever actually measured them, but there is an obvious difference in frame thickness between a C-10 and a C-20.

I was advised to just swap to 3/4 ton axles and springs to convert my Suburban to a 3/4 ton (mainly what I wanted was 16" wheels to run Load Range E tires).

[kwmech]

Originally Posted by 1976gmc20

I was advised to just swap to 3/4 ton axles and springs to convert my Suburban to a 3/4 ton (mainly what I wanted was 16" wheels to run Load Range E tires).

The bigger brakes are nice also, GM should never have put a pass car axle under this beast.

[CarolinaHD]

They are certainly not the same. 3/4 Ton frames are thicker and I'm sure theres other differences as well.

https://www.pirate4x4.com/forum/chev...-strength.html

Originally Posted by MAXPF

The difference isn't huge (the "V" designates 4wd OBS, while the "R" is 2wd OBS, so the V1500 and V2500 are 1/2 and 3/4 ton 4wd respectively) - the 1/2 ton has a .177" frame thickness while the 3/4 ton is .192". For comparison, Blazers (which were all 4wd in 1991 AFAIK) used the thinner .154" material. A couple years back my roommate was at another friends property up north. This friend has lots of Chevy trucks in various states of parted-outedness, and they decided one day to start measuring the thickness of the different frames. Here's what they came up with: 1988 1/2 ton 2wd suburban -- .162 1981 4wd Blazer ------------- .164 1987 3/4 ton 4wd suburban --- .190 1988 3/4 ton 4wd suburban --- .203 1970's unknown longbed frame- .196 1977 2wd 3/4 ton suburban --- .208 1986 3/4 4wd DIESEL longbed- .231 1979 1 ton reg cab & chasis -- .236 1984 2wd 1ton crewcab dually- .224 1982 3/4 ton reg cab longbed-- .230 The general consensus was that, within tolerances of measurement and supplied material thicknesses (which accounts for a +/- .010" variation or thereabouts) GM used at least 4 different thicknesses of material for it's light truck frames, depending on configuration and GVWR. 1 tons and some 3/4 tons used the thickest material, around .230"-.240" - nearly 1/4" thick. Most 3/4 tons .190"-.200". Some 1/2 tons, such as the 4wd Burbs and perhaps certain 4wd P/U configurations apparently used the .177" material listed in the GM manual above, while most 1/2 tons and all Blazers seemed to use the .154"-.160" material.

[1976gmc20]

Originally Posted by kwmech

The bigger brakes are nice also, GM should never have put a pass car axle under this beast.

They never should have made a 1/2 ton Suburban

I seriously wanted a 3/4 ton but when buying used you take what you can get when you can get it. Most of what we looked at was pretty rough. The one 3/4 ton Burban we found had a tailgate instead of barn doors. It was a 100 mile round trip just to start looking at anything, and a month of Saturdays was overwhelming when the wife/kids want to take an out of state trip soon ...

But that was 18 years ago so I guess we did okay. It just needs some TLC now.