c20 towing capacity

[paulbrgr9999]

Still trying to nail down the towing capacity of my c20. I want to pull a small toy hauler. Few hundred pounds short of 5000lbs loaded. I included pictures of the receiver and where the hitch bolts to the frame. Any opinions?

[Stu Pidd]

Disc, or drum brakes?

[paulbrgr9999]

Originally Posted by Stu Pidd

Disc, or drum brakes?

Drum. Trailer has brakes.

[jocko]

Look at the metal tag inside the drivers' door and it should tell you the MGVWR - that is your max combined vehicle+trailer towing number. Are you saying your combo (incl truck) is 5000 lb or the trailer itself is 5000 lb loaded?

[Old Truck Man]

The GVR rating on the metal tag really doesn't reflect the actual capability of the truck. depending on the overall condition of the vehicle & trailer skill of the driver road conditions ect. there isn't any definite answer. I see 3/4 ton trucks with a gooseneck trailer hauling large backhoes bulldozers and trailer loads of livestock past my corner every week. and its steep narrow curvy roads. those trucks are most times grossing in excess of 20,000 pounds. What im stating is there isn't a really definite answer to the question.

[jocko]

good point - I don't disagree with you. I TRY to not exceed the MGVWR in most cases, but it is a limited capability. Mods can increase the capacity.

[SS Tim]

The 67-72 trucks don't have a vehicle posted Combined Gross Vehicle Weight (rating) limit covering both the truck, cargo and any trailer. But in any event the trucks GVW and Max Axle ratings should not be exceeded. See the service manual or driver's handbook for load information. Drum brakes are not the best for towing in SoCal especially the grades on the 5 or 15. In fact the gearing going up is going to keep you running slow and stressing your cooling system. Need to consider the measured weight of the trailer, truck and all the cargo as a whole.

But there are factory publications showing "recommemned" equipment and loadings. This table is from the 69 RV brochure and outlines equipment and gearing to tow with. The load data is from the 70 service manual (last two years of front drums).

While GM I hesitate to post the table in fear of it being taken out of context by someone who sees a number without using common sense. In no way would I recommend that a SWB C10 haul a 5000lb+ trailer at 70 mph during a Sunday night get home rush that happens every weekend here. But since it is factory and a "recommendation" it would do well to temper any towing decision with their posted data. Remember these were for new, well maintained trucks. Age, wear and maintance short comings will show up at the worst possible moment. AAA + RV is a really good idea.

In your specific case it is important to note that whole setup is a modification of a step bumper and is not the sort of equalizer hitch GM recommended. If it were me I'd keep that at or below 2500lb max based on what you posted up. While it may very well go more, it has very little in the way of a torque box and basically just hangs off the tail of the frame. If you want to haul a toybox of any size I would recommend at least an inspection by a custom hitch maunfacturer (not just a kit bolt on shop).
Pretty certain they would agree with me that a true receiver hitch that runs up the frame and a spring load equalizer will make a safer freeway hauler. Remember here the winds can add a lot of side load and destabilize a trailer very quickly. If you have coils a set of airbags and premium shocks will help a lot too. Coils just don't have the inherent friction stabilzation leafs do.

[jocko]

good info Tim, thanks - so the GVWR on the plate is just the max for the truck (and its load) all by itself, yes? Excellent references posted above.

[SS Tim]

Yes, As an example here is a simplified beakout using rounded, assumed weights.

If you had 4.57gears and a 350 in your truck,
11,000lb is the recommended limit for everything combined or GCW.

Based on a 11,000lb GCW,

Truck 5000lb (front and rear axle weights combined)
add to that,
Hitch load 750lb measured trailer hitch loading weight (adds to truck cargo weight).
The truck now weighs 5750lb. Note, This is well under the possible 7500lb max or GVW (front plus rear axle as weighed at the ground).

To that we add,
Trailer 5000lb (weighed at the trailer axles)

So now our Combined Weight is,
10750lb or just below the max recommended GCW.

That means we can still add a little more,
250lb cargo

Or basically you, your dog and a cooler! :-)

The four important LOADED weights to remember here.
Combined Gross Weight (recommended by GM)
Front axle weight (max posted on the data plate)
Rear axle weight (max posted on the data plate)
Trailer axle weights (limited by the traile mfg)

Finally the max load on your data plates is for a truck equipped with the springs and tires to carry it, most were not. The "as built" number should be used unless you know the springs and or tires are capable of the max load within axle limits.
As a point in case, just last fall I found a really nice C30 dually with a max GVW of 10,000lb but it had be ordered light thus carried a 6,600lb "as built" rating!

[dajn]

Paying attention to weight ratings is like paying attention to how many tylenol you should take for a headache. I always take four to get rid of the headache quickly. Most people only take two because that's what the label says. Your pickup can handle way more than they recommend.

[paulbrgr9999]

Got it hooked up. Dragged it about 30 miles so far. Half freeway half surface street. Didnt have a problem. Tomorrow I plan on taking it about 85 miles total. I included pics.

I am worried now that one post says to stay under 3000lbs. Its 3400 dry. Two sport quads 1 dirt bike and other stuff probably brings my total weight for the trailer to 4700 lbs tops.

it crused right along on the freeway. I checked the hitch under the truck and nothing is lose. All the welds look good.

am I crazy to tow this rig?

paul

[SS Tim]

Well you wanted the information so I gave you the offical numbers.
Your hitch is a receiver tube attached to a regular step bumper.
http://67-72chevytrucks.com/vboard/s...d.php?t=628163
While they added a crossbar and extended to the lower frame flange the fact is it all just hangs a good distance off the rear of the frame. So it really is more of a deadweight hitch that a weight distribution style/equalizer hitch. All the load is spread over a very short frame length.
The spring bars are very good to have and help to reduce the tongue load on the rear axle by adding a twisting upload at the hitch. Problem is the very parts its trying to twist is the hitch in question.
As toyboxes go your is small and should not have too much of a problem. However I would suggest actually weighing the loaded trailer so you don't have to use the word probably. Most scales don't charge if they are slow and you don't need a printout.

[paulbrgr9999]

Thanks for the info. Glad you express your opinion. Dont worry if you think its something i dont want to hear. Sounds like you all know a hell of a lot more than i do. Up to now i have never towed anything more than a couple jet skiis. Maybe 2000lbs total. Im going to continue to look into ways to strengthen the setup.

So what is recommend then to boost my towing capacity at the hitch that would make it a safer setup?

paul

[dajn]

Godspeed sir. Don't underestimate the capabilities of your pickup.

[dajn]

An old 3/4 ton can do a lot.

[paulbrgr9999]

Originally Posted by dajn

An old 3/4 ton can do a lot.

A brand new chevy 3/4 ton? 35k? 40? Thats what their going for in calif. Smogged, computerized, and over priced!

I love my 1970 c20! I get so many complements everywhere I drive it. What year is that? My dad used to have one of those! People just love my truck. And so do I!

paul

[72chevyk10]

my thinking is the manufactures underrate whatever they make to stay out of lawsuits from the people that dont know how to handle a load safely. just underrate it to the point that most people wont get in trouble.. and the ones that do get in trouble tow or haul something totally unsafe anyway.

[Old Truck Man]

The trailer with the camper looks to be evenly balanced over the trailer axle. If soYou need to put some weight in the bed of your truck. that trailer will push the rear end sideways if there is not sufficient weight on the rear tires. That's why a gooseneck hitch is great.it plants the trailer weight in the center of the bed. As a rule of thumb the truck needs to be 25% heavier than whatever its towing with a bumper pull trailer.

[Blazerowner]

I just sold my 2010 ram and while it was a nice truck the 600 a month payment sucked. Over 400 a year to register. Insurance around 70 a month. I put 8000 miles on it in two years and that was because I did some moving and had to use it to commute for a bit. Trust me even if you have to throw some money in upgraded brakes or some other drive train component its worth it. I barely broke even on the truck when I sold it and it had 24k miles when I let it go after buying it with 16k miles. Doing the math I paid around 16k over two years to drive 8k miles. Needless to say I went out and bought a clean c10 to make myself feel better

[paulbrgr9999]

Originally Posted by Old Truck Man

The trailer with the camper looks to be evenly balanced over the trailer axle. If soYou need to put some weight in the bed of your truck. that trailer will push the rear end sideways if there is not sufficient weight on the rear tires. That's why a gooseneck hitch is great.it plants the trailer weight in the center of the bed. As a rule of thumb the truck needs to be 25% heavier than whatever its towing with a bumper pull trailer.

Ok, whats a gooseneck hitch? You mean a 5th wheel?

I am going to put a lot of stuff in the truck bed: beer, ice, gas, guns, ammo, fire wood, inflatable sex dolls, meth lab starter kit, you know the basics.

[Old Truck Man]

Originally Posted by paulbrgr9999

Ok, whats a gooseneck hitch? You mean a 5th wheel?

I am going to put a lot of stuff in the truck bed: beer, ice, gas, guns, ammo, fire wood, inflatable sex dolls, meth lab starter kit, you know the basics.

You might be ok if you add all that stuff and a fat woman to boot LOL. A gooseneck hitch has a 2&5/8 ball in the bed usually placed about a foot ahead of the trucks rear axle. the trailer has a hitch that rises up and over the tail gate and has a height adjustable tube with the coupling that attaches to the ball. Do a google search for gooseneck trailer. With a gooseneck you can jack knife the truck at a 90 degree angle to the trailer when necessary to get in or out of a tight spot.
there very easy to hook up to and pull much better & safer than a bumper pull. I have two gooseneck trailers . one is a 30 ft stock trailer and the other is a 24 ft flat bed. I pull them with a 3/4 71 chev big block 402 or a 78 3/4 with a 454. My brakes work on my gooseneck trailers however I rarely ever turn them on.

[Avitech]

I say run it. But, as with any towing, pay attention while you do it.

[paulbrgr9999]

Towed it 85 miles. That included the Cajon pass. The motor (350) was working hard. And I got 7mpg! It only gets 10 with no load. Only 3 mpg difference. Amazing.

paul

[tsetsaf]

Late to the party but thought I would chime in... looking at the pics if you choose to stick with the bumper receiver I suggest hooking your breakaway cable and chains to a secondary point on the frame or bed. My truck before the restore sheared the bolts on the frame while towing a 2500 lbs boat luckily the safety chains were fed through the frame. Only damage was to the front jack on the trailer. You are risking a lot of your property; go get a real receiver mounted.

[paulbrgr9999]

Can I replace the current bolts with something stronger? You got me worried now.