The Stovebolt Site Forums The Parking Lot Big Bolts payload question

may be dumb question but how do you know what a truck is rated to haul? Is a 1 ton truck designed to haul 1 ton? 1.5... Or what does the 1/2 3/4 1 1.5 2 ton nomenclature mean??

The tag in the door will say what the gross weight can be max. That's what the truck with driver and load will weigh max if sitting on a scale.

The payload is the weight in the door less the empty truck weight.

For example, my 52 3800 (1 ton) says 8,800 lb in the door, and weighs 4,400lb empty. I can put a load of 4,400 lb in the bed, and have.

If you want to get really picky there will be a max weight you can have allowed by the factory of each axle, and this adds up to the gross weight. So, the front axle is good for X,000 lb, and a different number for the rear, to load the truck to capacity you would need to think about weight distribution when loading.

Grigg

my 51 6100 gvw is 16000lbs on the tag. it weighs in empty at and including me at7500lbs.

Grigg -- Would an AD 3800 that isn't as rusty as yours weigh more or less than your truck??

Bwaaaaaaaa!!! :P

John

So is there any meaning to the 1/2 ton, 3/4 ton or 1 ton designation?

not really. . .

My 62 GMC has a GVW 14000LB, my 59 B61T has a GVW 120,000LB, the dodge has GVW 10,000LB. . .

it's different on every truck. . .

Mike. . .

I've heard this meaning from some of the old timer truckers.

A 1/2 ton truck can have an additional 1/2 ton of weight put on it's front axle. Likewise the 3/4 and 1 ton trucks can have an additional 3/4 and 1 ton of weight applied to their front axles. While the rear axle is designed to carry the majority of the weight, a small amount of it will be transferred to the front axle as well. Proper loading of a truck (particularly an 80,000 lb GVW semi) will adjust the load position (using a sliding fifth wheel on a semi) so that you have not overloaded the front or rear axle.

My 1958 1 ton, was likely sold as a cab and chasis to Knapheide where they attached the grain bed, sold it to a farmer... and 55 years later ends up in my hands. My front axle is rated at ~4000 lbs and the rear axle is rated at 7600 lbs. Documentation from other models (not the cab and chasis) tells me that the GVW is 9600 lbs. These numbers don't add up! Maybe the axles are stronger than the frame? Maybe they didn't want to have a 1 ton truck that could hold nearly what the 1.5 ton truck could hold?

Another interesting tid bit about my truck. I don't have a stated GVW. Chevy never stated one for the Cab and Chasis. There is not a GVW number stamped on my original data plate inside the door. Knapheide didn't state a GVW after manufacture for the truck. I wonder what would be the first thing to break if I started loading it up?

More, I have the wood bed floor, but over it is a 9' X 50" X 0.25" steel plate

1/2 ton, 3/4 ton, etc., are the load capacity of a truck. A half ton can safely carry 1000 lbs, 3/4 can carry 1500, & so forth. Your gross weight will be the combination of your basic weight and the load.

Gross weight is not determined by the front axle capacity alone, but a combination of front and rear. Thats why dump trucks with 100K load cap may have 2-3 axles out back, but still only one up front. Also look at the max weight on your tires, it is much lower than your gross weight, but the individual wheels carry only a fraction of the weight.
It is true that when decelerating the center of gravity shifts forward, but this is accounted for in the design of the vehicle according to axle & load position. You may carry a smaller item that bumps you up to gross weight (say, like a heavy item of machinery or an electrical transformer), it is up to the driver to remember to center & secure the load slightly in front of or over the rear axle/s to prevent overloading the front axle.


There is a formula that takes the combined front and rear axle capacity, the distance from the projected load center (typicaly a set distance in front of the rear axle/s), the distance from that point to each axle, and provides the determination of a vehicles gross weight.
When the local transportation police pull over a truck, this is also how they manage to get the gross weight and load distribution with only a couple roll on scales.

Freq2002,

Respectfully have to disagree with you.

I know the military calls something a 1.25 ton if it can carry 2500 additional pounds of payload (i.e. M880). However, civilians call it a strong 1/2 ton or a weak 3/4 ton. I used to own a S10 rated to haul 1000 lbs. It was NOT a 1/2 ton, but commonly called a 1/4 ton. I've got a 1958 model 38. I've got a little more than 2 ton's carrying capacity. It's a 1 ton.

Based upon your logic, 379MV6's Mack B61 would be considered about a 50 ton truck?

There's some truth in most of what has been said on this thread, but there's also a lot of misinformation.

First of all, the 1/2 ton, 3/4 ton, etc. goes back to the 1920's and 1930's and referred to what payload a truck could carry. It applied only to a complete truck, cause there would have been no way for the manufacturer to know what kind of a body would be mounted on a cab/chassis or what it would weigh. Tt least as far back as 1947, there was a GVW rating on all trucks and there remains a rating on all trucks today.

The Gross Vehicle Weight Rating on a truck refers to the total allowable weight of the truck, body, driver and passengers, fuel and other fluids. Always has.

Every truck has a Front Gross Axle Weight Rating(FGAWR) and a Rear Gross Axle Weight Rating(RGAWR). These ratings are based on the lesser of the tire, wheel, frame, axle and spring capacity. What this means is that the lightest component determines the GAWR. Putting great big tires, dual wheels, heavy duty springs and so on doesn't mean anything if there is a smaller component in the chain. Additionally, there is a brake rating that can, and often does, limit the GVWR to less that the sum of the GAWR's.

In the old days, what we call a 1/2 ton had GVWR rating of 4,400 lb. It crept up in to the 5,000's over the years and then, when the EPA decided that we needed catalytic converters on trucks with GVWR's of 6,000 lb. or more, all of the manufacturers came out with heavy 1/2 tons with 6,050 lb. GVWR so we could use regular fuel. a new GM truck today that we know as a C1500 has a 6,400 lb. GVWR.

A 3/4 ton used to have a 7,200 lb. GVWR until the EPA decided that catalytic converters were needed on trucks up to 8,500 lb. GVWR. All of a sudden there was a new truck from each manufacturer rated at 8,600 lb. GVWR. Today, the GM C2500 is rated at 9,200 lb. Ford's F250, I believe, is 8,800 Lb GVWR.

The net effect is that the old ratings have no meaning and the only way to compare capacities on trucks is to weigh the completed truck and subtract the weight from the GVWR. You'll find that in many cases, a Ford will have a higher GVWR, but because it's heavier, a lower payload than most GM trucks.

As to the body installation, the dealer has almost always handled that with an outside body manufacturer. The dealer sent the truck to a body manufacturer or distributor and sold the truck to the final user. Even today, the body people seldom take ownership of the truck.

The problem is that a lot of people don't know what they are going to carry and tend to buy a truck that is too small. Utility bodies are a prime example of this. The driver puts 5 widgets on the truck for a job, uses 4 and the fifth stays on the truck. Over a year or two, the truck gains a lot of weight and nobody can figure out why tires and brakes and the like wear out, not to mention bearings.

As you probably have figured out, I sell GM trucks for a living and have been doing this for 45 years. I try to get my customers to use GVWR's, but it's hard to break the thinking of a lifetime. Sadly, most truck salesmen have only a very basic understanding of the facts, so it's pretty easy to get bad advice.

Just as a side comment, one of you mentioned how the states regulate axle and total weights. There is what is called a bridge formula that uses the distance from the center of the front axle to the center of the rear axle to calculate the maximum allowable weight for a truck. The longer the distance, the heavier the total weight allowed, but every state also tells you what the maximum load you can have on a single or tandem axle and you have to load your truck so that both ratings are not exceeded. This will explain why you used to see boat trailers hooked onto the back of trucks and why, at least in California, dump trucks and cement mixers have a hydraulically operated rear axle that is lifted up when the truck is empty.

I get a little longwinded on this subject, so I apologize if I wasted your time

You certainly haven't wasted anyone's time and your dissertation on the GVWR is by far the best that I have ever read. Your post needs to be immortalized in the Tech Tips.

Thanks,

Don

Steve,
That some great information!
I too knew some of the other post were mostly BS, but I could not find the words to explain it / correct them like you did.
Thanks,
Grigg

No, please blow away! The more people chew these things up the better, gets more solid info out here for us to paruse.

I noticed my '00 half ton was a great deal heavier than my '65 three quarter ton, by a couple thousand lbs. Then again, my half ton has a LOAD more fun stuff that came in it.
As a rule, since most folks dont have scales handy to chack thier weight, I dont load anything more than the truck can carry and sit level to the ground, wether it's in the bed or on the hitch. If it's sitting nose up, I'm overloaded, it's that simple.

This whole "strong 1/2 ton" and "weak 3/4 ton" sounds more like military math than anything, afterall an elephant is just a mouse built to government standards! I know weight and balance and how they can accurately weigh a tandem trailer rig with 2 portable roll-on scales, but how they make a "half ton" equal two is beyond me!
Regardless, I do realize the chassis is built to cary a set gross load, HOW it is caried is determined by the configuration of the truck. A heavier setup like my dumptruck bed may give me a lighter payload than the same chassis with a fixed flat bed due to the weight differences in the beds and gear. So yes, I can see where my '56 2-ton truck carries a lot more than 4,000 lbs. One would think that when talking about standard pickup trucks tho, it would be a set weight,...
Ah well, I quit trying to make sense of all this stuff. If I really need to carry more than a 1'000 lbs in my half ton, I'll subtract my basic weight from the max weight and call it a load capacity. Still wont load it past level tho, just to be safe!

Even way back in the 20's and 30's they were smart enough to know that the critical information in loading a truck was how much weight can the front and rear axle hold. As has been correclty pointed out, the truck + bed or hitch or whatever weights a certain amount, meaning that your axles are already partially loaded.

When calculating a max "added load", it is easiest to assume a center of gravity point where all the load is applied. You can then take the GVW of the truck, substract the "unloaded weight of the truck" to find out the max load you can add to the truck.

Now lets look at this for a minute. What if we put all this weight on the front bumper? Well then you'd be overloading the front axle and removing weight from the rear axle. What if we put all this weight on the rear bumper. Then we'd be removing weight from the front axle and possibly overloading the rear axle. (We've all seen this vehicle pulling a trailer down the highway dangerously!) So it's plain to see that the center of gravity should be placed somewher in front of the rear axle but behind the front axle.

So how you gonna figger out where to put your load without some fancy compooter back in the 1920's? Easiest way is to know how much additional weight can be applied to the front axle. This is easy to find out by knowing the max front axle weight and putting your front tires on a scale.

Lets say your front axle can take an additional 2000 lbs of weight on it, and you calculated your max added load to be 6000 lbs. It's easy to see that 1/3 of the added load should be applied to the front axle.

So measure the distance between the front and rear axle. Find the point that is 1/3 this distance in front of the rear axle. Apply all your weight at that point. You've now got a front and rear axle that are fully loaded and you are carrying your max load.

Now, we can talk about safety factors, and frame strength vs. axle vs. tire vs. brake strength, and modern semi's with dual rear axles and sliding fifth wheels and inertia concerns and all kinds of other things we have now a days. And I sure hope they are taking these things into concern with the 80,000 lb trucks cruising down the road at 70 mph next to my 3000 lb minivan with me and my kids in it. But that's NOT what they worried about back then. Heck the guy loading the truck was probably not literate and didn't know any math. But it was easy to tell him to put the center of the load 1/3 the distance forward of the front axle.

Course I wasn't alive in 1920, more or less loading trucks. I'm just explaining it the way it was explained to me. The way it was explained to me makes sense. Anybody in this forum that's got first hand experience from this era loading a heavy truck?

I see people pulling trailers around here with the rear end smashed down, obviously overloaded, tooling down the highway at 70MPH like it's no big thing. Makes ya wonder about people,... Couple years back someone was doin it on I-5 and they got a case of the tail wagging the dog and wiped out the entire 3 lanes of traffic and killed someone in another car.
I dont worry so much about the big trucks with all the stuff you have to learn to get your CDL these days, and the state patrol wandering around with thier mobile scales, those guys tend to try alot harder to do it right than Joe Blow in his quad-cab super extended frame 4x4 dualy pulling the largest mobile home on earth,... Wonder what would happen if they started making people roll through weigh stations in those rigs?

Back on topic tho, I can see where using the max front axle capacity would have been an advantage way back when, still looks odd on paper to me. But then I really suck at algebra!
However, were I to use that same logic in loading the bed of my newer truck, it seems not to be a good method, not on that truck anyway. The axle is nearly centered in the bed, given that, if I add an evenly distrubuted load in the bed, I'm pretty sure I can grossly overload the rear axle before registering an additional half ton on the front. Sure would be nice if they called a truck by it's actual capcity, but it's pretty plain to me that they dont. Hence why I'll just load it till the gap between my fender and tire is the same on front and rear, or the truck looks level to the ground from the side. May not be max capacity, but it makes for safer handling.

My '45 Mack EH is rated at 19K as just a truck,but now has a 5th wheel;I guess my GCVW would be the 19,000 plus whatever the trailer's rated at,right?
Speed

GCVW is not the GVW of the pulling vehicle plus the trailer rating. It is calculated diffently and takes into consideration the power of the tractor/truck, it's driveline components including brakes, etc. So you could pull a very heavily built trailer but it would not increase the gross COMBINED weight rating of the pair just as a small trailer would not increase the truck rating. Each component has a specific rating that should not be exceeded but the total of all rated components should not exceed the GCVW. What it comes down to is the sum total of the "least" rated components that determined the GVW. So as Steve Ley pointed out putting larger heavier tires on the original smaller wheels/rims doesn't really change a thing as far as calculating a GVWR or GCWR. Larger capacity wheels and tires together still would not increase axle capacity if they exceeded the axles own rating.

Interestingly enough, it is the Final Stage Manufacturer who must declare what the GVWR and GCWR are on a new vehicle. This final stage manufacturer is your local body installer/upfitter. He must also calculate the CG for each unit and declare tire/wheel size along with air pressure. The motor companies have put this monkey on the backs of small business even though they built the original vehicle. This also means accepting every concievable safety standard as declared on the Incomplete Vehicle Document. This explains why one so often see's tag axles added to trucks that carry no capacity increase on the GVW decaration.

As far as the origination of the terms one ton, 1-1/2 ton, etc. I must side with those who claim it refers to the front axle carrying capacity. That is what I was taught by the old timers back in the 60's when I got into truck equipment business. Some of those guys were around in the 20's and 30's.

the door jam will tell you. . .

look for somthing saying "GVW" or "GVWR" take the truck's weight and subtract it from that number that will give you the pay load. . .

Mike

Well i see i was right on that statment. . .

Mike