Towing capacity concerning frame strength

[72kool]

Long story short I've been looking for a new tow vehicle and have had no luck with today's market.
My truck is a 1972 c20 that's stripped currently. I need a 4x4 that's capable of towing 10k lbs. Assuming I have the proper brakes, axles, suspension etc, can this frame handle towing 10k lbs? It's hard to get a sure answer on the threads I've read. Alot are talking about the factory suspension and brakes but no mention of the frame. Any help would be appreciated

[kwmech]

Towing that much with a 3/4 can be marginal but it can be done short term if careful. Most 3/4 tons are usually rated up to 7500 with an equalizing hitch. 10k plus is getting into 1 ton status--dually preferred. It is not only frame strength but control and stopping power. 1 ton frames are thicker and have more beam height just for that reason. What are you actually towing that weighs that much? I've come close to that with my 68 3/4 2wd. I went over the scales at the scrap yard a few years back at 14,300 pounds with metal in the bed and a trailer that was loaded also. It was a harrowing 55 mile trip with 4 wheel drum, but I went slow and cautious. Will I do it again----nope, too much at risk

[Big Kev-O]

Post number 7 in this thread has the factory literature regarding towing, it shows a load capacity chart which indicates a max GCW of 11,000 with a 350 engine and 4:11 rear axle.

http://67-72chevytrucks.com/vboard/s...d.php?t=629019

Since our trucks weigh about 5000lbs. you max trailer weight would be around 5000lbs. A 10,000lb trailer is way over the recommendation for our old trucks. I have towed my 5500lb boat trail on a short trip across town. I would never try it on the highway. IF you need 4x4 that can tow 10,000lbs you are going to need a newer 2500 or 3500 preferable with a diesel. I wouldn't even try it with a gas engine unless it was an 8.1L. My 6.2L Escalade strugles with my boat on grades.

[Grumpy old man]

I'll make it easy , NO , Buy a newer truck.

[72kool]

I tow alot of different trailers. Mostly single car trailers at 7k. But also have a camper that's 8k loaded. I would like to be able to move up to a double car gooseneck in the future. It would probably only be towed twice a year but a distance of 500 miles...that's why I want something strong enough. I understand needing a dually and that is the plan. I have heard the c20 and c30 used the same frames but finding actual frame specs are very difficult. I know what drivetrain I need, trying to find a strong enough frame

[SkidmoreGarage]

All of these posts cover it, but I wanted to throw out that the modern trucks frames are engineered and tested before they ever see the road. I wouldn't trust one of these old frames to reliably tow beyond the recommended weight for more than an emergency tow across town. It all goes wrong very quickly on the highway.

Just jack up one corner of a 3/4 ton frame in a complete truck and you can see how much deflection occurs before the other wheels start to lift. Just imagine that this bending is occuring continuously over its lifetime and even more under a heavy load. High quality materials won't make up for the R&D in a modern truck.

[kwmech]

Originally Posted by 72kool

I have heard the c20 and c30 used the same frames but finding actual frame specs are very difficult. I know what drivetrain I need, trying to find a strong enough frame

there is a huge difference between the 20 and 30 frames in both thickness and beam height. Even the 1 tons have different frames depending on GVW. I have a 1 ton longhorn and I also have a 1 ton dually that used to be a Class B motor home. Needless to say the motor home frame is vastly different

[CastIron]

Isn't the frame on a C20 longhorn the same as a C30 frame? It looks much larger than a C10 at least.

[RichardJ]

Is the motorhome frame a C30 or a P30 series chassis? If you go to the GM Heritage page and click on '70 Chevrolet Motorhome, it sends you to the P30 chassis page and shows a PE3xxxx FC Chassis (Forward Control)

[Steeveedee]

Originally Posted by CastIron

Isn't the frame on a C20 longhorn the same as a C30 frame? It looks much larger than a C10 at least.

Yes.

And looking at the charts brought home the knowledge that I'm exceeding the manufacturer's recommendations by about 2000 pounds when I'm towing my trailer. I have a Longhorn with a lot of weight-adding goodies like the BB engine and AC. All that stuff adds up, and that shell isn't light, either. I guess I'll take it to the scales and find out. I don't go over 55 when towing, anyway. I added disc brakes as well, for more braking safety. The trailer has electric brakes.

[kwmech]

Originally Posted by CastIron

Isn't the frame on a C20 longhorn the same as a C30 frame? It looks much larger than a C10 at least.

Yes it is, but my motor home chassis is a 157'' wheel base. Frame under that is 8'' wide all the way back past the rear spring hanger. Whereas the longhorn frame is 8 also (just under the cab for a very short while) but tapers down to 7 ish before the rear cab mount and continues to taper a little to the rear. There is a 14k tag on my C30. Gonna be fun re-registering that thing in calif with the 14k designation

[72c20customcamper]

I'd be more worried about the transfer case than the frame. 4x4s were given less towing capacity than their 2wd brethren in excess of the few hundred pounds the 4x4 had over the 2wd.

[Integrity Imports]

I have a 71 c20 long box. 350, sm465, I bought it with a 75-80 ish 14 bolt full floater with 4.11 gears. I replaced the open diff with a yukon grizzly, added a class 5 hitch, Modern 17" wheels and e rated tires, and have went through the brakes and bearings. Redarc brake controller.

Towing a 10k lb toy hauler is a white knuckle ride.

Towing a 5k equipment trailer with 5k on it tows just fine if the tongue is loaded right.

Towing a 4-5k lbs or less is fantastic. Sometimes its exciting pulling the boat out of steep launches.

You can feel the frame twist with any of the loads on it. Gotta watch the stopping distance with any trailer.

Sometimes the diesel is busy and the old girl has to earn her keep.

[72kool]

I'll give some more info. I know to meet my goals I need a very stout setup. I'm looking at a 1989 or 1992 Chevy 8 lug 2500. They are both junk body and interior. They are both 350 engines and both have pulled what I need to multiple times.
I want to use one of them to get my truck running again. The options are either to mount my body on the newer frame and drivetrain, but as mentioned before these are not the best years for such task,but doable with fab work and a little lift to put it simply.
The favorite answer when talking about this kind of project I have gotten is to just put the drivetrain in my pickup using factory chassis. I don't think the chassis on my 72 is up to the task but wanted to make sure I wasn't selling it short. Both options require alot of fab work but that is what I love to do and am fairly well setup for it in my shop. Its simply which is the best suited for what I want. I appreciate all the help, this site never ceases to have a ton of info and is a great resource to have

[MARKDTN]

Originally Posted by 72kool

I'll give some more info. I know to meet my goals I need a very stout setup. I'm looking at a 1989 or 1992 Chevy 8 lug 2500. They are both junk body and interior. They are both 350 engines and both have pulled what I need to multiple times.
I want to use one of them to get my truck running again. The options are either to mount my body on the newer frame and drivetrain, but as mentioned before these are not the best years for such task,but doable with fab work and a little lift to put it simply.
The favorite answer when talking about this kind of project I have gotten is to just put the drivetrain in my pickup using factory chassis. I don't think the chassis on my 72 is up to the task but wanted to make sure I wasn't selling it short. Both options require alot of fab work but that is what I love to do and am fairly well setup for it in my shop. Its simply which is the best suited for what I want. I appreciate all the help, this site never ceases to have a ton of info and is a great resource to have

Isn't an '89 2500 still a square-body? I was thinking 1/2 tons changed body style in 88, 3/4 tons in 90, and 1-tons in 92? There is info around on putting a 67-72 body on a square body frame. Not easy, but possible.

[tdangle]

Originally Posted by MARKDTN

Isn't an '89 2500 still a square-body? I was thinking 1/2 tons changed body style in 88, 3/4 tons in 90, and 1-tons in 92? There is info around on putting a 67-72 body on a square body frame. Not easy, but possible.

I bought a 88 3500 which was the new body style. 2500 and 1500 were new style also. 1st year for extended cab. Truck was a brute with 454 3 speed auto and 3:73 gears. Long gone now, actually like my 70 better.