GVWR of regular cab 81 short bed

Hey all, I've done a bit of searching on this site and others but didn't really find what I'm looking for. I'm trying to figure out what I can tow with my truck. It's got a 5.8l and 3.55 gears. The truck started life as a 2wd but was converted to 4wd, using all the 4x4 stuff from a '95 extended cab. As such the truck is effectively as good or better than an 81 SWB regular cab 4x4.

Other stuff to help it get down the road are the rear sway bar from the 95, an E4OD with a cooler in front of the radiator, and limited slip diff.

The door tag is long gone so no help there.

The Owners Guide I have shows this, but apparently deriving your GCWR (I assume this is the total rolling mass of truck and trailer?) is dependent on knowing your GVWR.



So of the 4 options for GVWR (5500, 6050, 5700 or 6250), which would apply to a SWB regular cab? At first I thought "well, the smallest one, since it's the smallest truck". But then the thought occurred to me that it might be inverse of that, in other words, the smaller the trucks weight, the more room that leaves for carrying capacity. Thoughts?

The general feeling I get from all these numbers is that if the truck is mostly unladen, I should be good to pull about a 5000lb load (trailer and cargo together). Does that sound about right, or low/high?

Thanks.

Good question!

I don’t have an answer, but an observation if you will.

My 1992 Bronco has a 6300 GVWR.

Hopefully someone has a similar truck to yours and can tell you their GVWR.

Now my 2WD 81 F100 Flare Side with a 300 six, T18 now a NP435 and 2.75 rear gear has a 4700 GVWR.
My parts truck 2WD 81 F100 LB Style Side with a 300 six, SROD 2.75 rear gear has a 4700 GVWR.

Now I know from other posted autos have a higher tow rating than sticks.
Same if the rear gear is lower (higher number) can tow more.

Now I built my Flare Side as a back up to pull my open deck car trailer and I would say it's got to be 5000 lb.
The six will get the job done just not fast LOL
Dave ----

Here is that same page you have.   https://www.garysgaragemahal.com/towing.html

But also your VIN should give you the original GVWR of your truck.  Same page - just find VIN decoder section.

Maybe some of that helps.   As for the 4x4 conversion, that's up to you to decide how much extra you think you can safely pull after you did a conversion.   If you are still on the original rear leafs, wouldn't that figure in as well, since the tongue weight is going to be there mostly?  

To me this all seems like a guess at this point.  Plus there is no algorithm to figure out 40 years of deterioration to add into that.  The original specs aren't going to account for fatigue, rust, wear.  

I know most times you deduct some for 4 wheel drive and I see that is the case with looking at the 86 towing guide. I know with my 4X2 GMC truck it is the same it tows more than the same equipped 4X4 model.

rcarlisle wrote

But also your VIN should give you the original GVWR of your truck.  Same page - just find VIN decoder section.

Ah, thanks for that info, I was not aware. Mine is a D - 5001-6000lb range. Kind of what the owners guide already showed, although not a specific number. I guess it narrows it down by half, as it would eliminate the 6050 and 6250 GVWR's, leaving only 5500 and 5700 as possibilities.

rcarlisle wrote

If you are still on the original rear leafs, wouldn't that figure in as well, since the tongue weight is going to be there mostly?  

Nope, swapped in the 4x4 springs from the '95 donor truck. They are 1/2" wider than the originals. Also more leaves, and plenty stiffer.

rcarlisle wrote

To me this all seems like a guess at this point.  Plus there is no algorithm to figure out 40 years of deterioration to add into that.  The original specs aren't going to account for fatigue, rust, wear.

Agree that it is all a guess, as my truck is pretty Frankenstein at this point. But the consumables (spring eye bushings, shock absorbers, etc.) are all new, so that should mitigate some of that.

I think my original assumption that my limit is about 5000 lbs must be pretty close to correct, I would feel comfortable towing that I think, although I have yet to try. I am working on getting a Reese hitch from the '95 donor truck cleaned up and installed on my truck. It is super heavy duty, I am sure it could safely tow a lot more than 5k lbs.

81f100custom wrote

I know most times you deduct some for 4 wheel drive and I see that is the case with looking at the 86 towing guide. I know with my 4X2 GMC truck it is the same it tows more than the same equipped 4X4 model.

That makes sense, since the 4x4 has to carry the extra weight of the front diff, transfer case, driveshaft, bigger springs, and all that.

FuzzFace2 wrote

Now my 2WD 81 F100 Flare Side with a 300 six, T18 now a NP435 and 2.75 rear gear has a 4700 GVWR.
My parts truck 2WD 81 F100 LB Style Side with a 300 six, SROD 2.75 rear gear has a 4700 GVWR.

Now I know from other posted autos have a higher tow rating than sticks.
Same if the rear gear is lower (higher number) can tow more.

Now I built my Flare Side as a back up to pull my open deck car trailer and I would say it's got to be 5000 lb.
The six will get the job done just not fast LOL
Dave ----

Yep the autos have the torque multiplication of the converter that gives them a higher tow rating.

My 82 F150 2wd with 302, C6 and 2.75:1 has a 5250 GVW and based off the F100 tow capacties on here since I cant seem to find my '82 owners manual it puts mine at 6800 lbs with a trailer weight of up to 2000 lbs.  With my upgrades to the engine, the C6 getting the E4OD guts for the planetary to get lower first and second gear and swapping from a 2.75:1 to a 3.25:1 axle ratio I think mine should be well over enough for towing a pontoon boat if I ever got one or a trailer with a off road flare side if I can locate one to build into a mud truck.