"As Du Volant" (skuhnphoto)
09/29/2014 at 15:28 • Filed to: towing
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"As Du Volant" (skuhnphoto)
09/29/2014 at 15:28 • Filed to: towing | 9
| 10 |
Along with this morning's post about the !!!error: Indecipherable SUB-paragraph formatting!!! there's been a lot of talk about truck duty ratings, what they really mean, and how they work in a practical application. But how do you figure out if a truck is up to the task, anyway?
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Well, I'll tell you.
There are three key statistics you'll need to keep in mind when calculating job ratings for a truck- Gross Vehicle Weight Rating (GVWR), Gross Combination Weight Rating (GCWR), and maximum towing capacity.
"But if the truck is rated for 10,000 pounds towing, and my trailer weighs less than 10,000 pounds, I'm good to go, right?" you might ask. Well... sometimes. If any one of these three weights listed above is exceeded the truck is overloaded- and the kicker is, you can be under the max payload and towing numbers but still be over the GCWR, which is why properly job rating a truck is so important to do before making a purchase. You'll also need to know the truck's stats as rated from the manufacturer. You'll be able to find this information for new and late-model trucks on the truck manufacturer's website, and your dealership should be able to tell you as well. For older trucks you'll have to do some research. If you know some of the numbers but not all of them, it's possible to do some math to fill in the blanks. I'll put a list of calculations at the bottom of this article to help with that.
So let's say you're interested in buying a new 2014 Ram 1500. I'll use one of the more common packages, an Express Crew Cab with the 5.7l V8, 6-speed automatic, and 4 wheel drive. These are typically found with the 3.55 axle ratio but there's a 3.92 option as well. I'll use the 3.55. This truck's stats are:
GVWR: 6900lbs
Max Payload: 1540lbs
Curb Weight: 5357lbs
GCWR: 14,150lbs
Max Trailer Weight: 8600lbs
Also worth finding out is how the manufacturer calculates these numbers. In Ram's case it's with a 150lb driver and nothing else. You can find this on the fine print for their published tow ratings. That's going to change soon, though. !!!error: Indecipherable SUB-paragraph formatting!!! , which will include two 150lb people in the truck.
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We're planning to take the truck on a road trip. Two parents, two kids, luggage and gear for 4, and an 8500lb camper.
Warning: Boring math ahead. For a quick summary skip to the bottom.
First , calculate the weight of all the people and things inside the truck. If we've got a 200lb dad, 150lb mom, and kids weighing in at 100lbs and 70lbs that's 520 pounds of people in the truck- and if their luggage and gear weighs another 300, that means we're adding a total of 820 pounds to the truck. But remember, Ram already figured a 150lb driver into their numbers, so we need to subtract it back out for a total of 670 pounds . That's our payload not including the trailer. Keep in mind that the weight and payload figures assume a stock truck. If you've added 200 pounds worth of bull bars and skidplates you'll have to add those to the payload number as well.
Second , add the trailer's tongue weight. Conventional trailers typically have a tongue weight of 10-15% of total trailer weight, and gooseneck/5th wheel trailers are typically 25%. Your trailer should have this figure clearly marked, and if it doesn't the manufacturer can supply it for you. And yeah, sometimes you'll have no idea and you'll just have to estimate- do it conservatively. Let's say our camper in this example has a 10% tongue weight, so that's 850 pounds that it's exerting on the truck's suspension and tires. Add that to the 670lbs from above, and our total payload is now 1520 pounds , still under the truck's max payload figure. So far so good.
Third , add the total payload to the curb weight of the truck. Curb weight was 5357lbs, payload was 1520lbs, so that's a total of 6877 pounds for truck and payload together. This is the Gross Vehicle Weight (GVW). This 6877lbs is less than the truck's GVWR (the R stands for "rating") of 6900lbs, so the truck isn't overloaded... yet. If you've exceeded the truck's GVWR at this point you need to either find a way to travel lighter or look at a heavier-duty truck.
Fourth , subtract the trailer tongue weight back off your GVW number from above. You're about to calculate the total weight of truck and trailer together (Gross Combination Weight) and don't want to double count this weight. 6877 - 850 = 6027.
Fifth, add your trailer weight, 8500lbs in this case. 6027 + 8500 = 14,527 pounds. This is the truck's Gross Combination Weight (GCW). It's greater than the truck's GCWR of 14,150 pounds, which means this truck is overloaded even though we were below both the max towing and max payload figures.
Yes, this is a very well-crafted example and you'll probably never see real-world numbers this close to maximum without going over. It's meant to just illustrate the point that even though your numbers might look like they're lower than the truck's rating, you could actually be overloading it- it's not so simple as saying "Well, it's rated for 8600, my trailer is 8500, I'm all set." I've often run into this with work trucks- take a crew cab truck, add four construction workers, their tools, and a trailer with 10,000 pounds of equipment and bingo, overloaded truck.
Just one more thing... if you're planning on utilizing close to the truck's maximum capacity on a regular basis, you really should consider buying something heavier than a half-ton (F150, Silverado/Sierra 1500, Ram 1500, Tundra, Titan) truck. They're designed more for daily driving and light hauling and are really only meant to tow/haul very heavy loads once in a while. For the truck in my example above: if this is a two or three times a year sort of excursion, the half-ton is fine. If this is an every weekend or even every month sort of job, they'd be much better off with a 3/4 ton truck. They're just better designed for the stress.
To sum it up:
Calculate the weight of all the people and objects in the truck, and don't forget non-stock accessories.
Subtract the occupant weight the manufacturer already allowed for, if any.
Add the trailer tongue weight. This is your total payload. If you exceed the truck's payload rating, the truck is overloaded.
Take this number and add it to the curb weight. This is your GVW. If you exceed the truck's GVWR, the truck is overloaded.
Subtract the trailer tongue weight, then add the max trailer weight. This is your GCW. If you exceed the truck's GCWR, the truck is overloaded.
Up above I promised some ways to find out various truck weights. Here they are:
GVWR: Check the VIN plate in the driver's door jamb.
Curb Weight/Max trailer weight: If you can't find it published, research online/call a truck body upfitter and ask.
GCWR = Maximum trailer weight + Curb weight + Occupant weight (if the manufacturer uses this). This is often rounded up to the nearest 50 pounds.
Max payload = GVWR - Curb weight. This is often rounded to the nearest multiple of 10.
Max trailer weight = GCWR - Curb weight - Occupant weight (if used).
505Turbeaux
> As Du Volant
09/29/2014 at 15:33 |
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you write so much awesome content I swear you are going to dry up or burn out. Here's to hoping Jalopnik starts giving you a paycheck...
RallyWrench
> As Du Volant
09/29/2014 at 15:38 |
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Andrew, front page this!
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As Du Volant
> 505Turbeaux
09/29/2014 at 15:43 |
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Heh, thanks.
This is actually from a doc file I have saved to train our salespeople on job rating (because if we sell a customer a truck that isn't up to the job it's OUR problem). I just added in a little filler to make it better to read.
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505Turbeaux
> As Du Volant
09/29/2014 at 15:44 |
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if those images exist in the working doc I am coming to work for you whether you like it or not
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As Du Volant
> 505Turbeaux
09/29/2014 at 15:50 |
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They don't... but I think they should.
HammerheadFistpunch
> As Du Volant
09/29/2014 at 16:12 |
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Great writeup, I was just thinking about this the other day. I'm somewhat obsessed with weights and ratings lately and I have no idea why.
deekster_caddy
> As Du Volant
09/29/2014 at 16:37 |
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Well said! Your "well crafted example" is not at all unusual, especially for a family heading off camping with their travel trailer for a week of vacation. If you use a travel trailer, even though they are usually lighter than the 'tow capacity', you almost always need to look at 3/4 ton models.
"3/4 ton?" "What? The 1/2 ton can handle 3/4 of a ton just fine!" "No, it's actually 1 tons" "wait, what? No, you are mixing up the numbers!"
KusabiSensei - Captain of the Toronto Maple Leafs
> As Du Volant
09/29/2014 at 19:56 |
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Also, if you want to add more pedantry (because you have the big bases covered)...
You also should not exceed the Gross Axle Weight Rating of either the front or rear axle. If you do, The Truck Is Overloaded .
The reason this can crop up is when using a bumper hitch, the force downwards is being carried by the rear of the truck, and the components to carry that are the rear axle and rear part of the frame.
This one isn't that easy to calculate, so carefully head over to your friendly local truckstop that has a set of scales. Park the rear axle on the scales and take a reading of the weight at the tires. You will need to add both sides if the readout is done by left and right side.
The rear axle on the Ram 1500 in your example is 3900lbs GAWR. Now while it can take some doing to exceed rear GAWR without exceeding any of the other weights (3900 RGAWR - 2246lbs on the rear axle from the factory = 1654lbs, which is more than payload, but payload is in the bed, while tongue weight is offset from the axle), one does need to keep GAWR in mind.
But as you mention, if you are getting close to any of these limits, it's really time to look at a bigger truck.
dezerthooligan
> As Du Volant
09/30/2014 at 13:31 |
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I can tell you coming from the RV media industry, that this is a touchy subject. Not only do you have to look at the published numbers, but also the actual weights. Trailers almost never weight what the mfgs list for dry/base weights. Same is also true for trucks. My FJC weights more "base"+fuel.... while my F450 weights less than the dry weight listed, even with fuel. It's all about options chosen. The best thing to do is CAT scale each item, then the entire load. Also the new SAE guidelines are going to change all these numbers...
PlayswithCars
> As Du Volant
10/02/2014 at 09:21 |
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Thank you for this! I rant about this kind of thing so much even my wife notices it as we drive down the highway, and will say "Isn't that trailer a bit much for that truck?" Typically, it's a travel trailer, and presumably, the buyer listened to the RV dealer who said "Sure, you can tow this here 30' TT with your Explorer SportTrac - it's a lightweight model!"
My other big peeve are people who won't buy a different drawbar than the standard 2" drop ones even with their taller truck, and end up having the tongue of the trailer up at a 15° angle going down the road.. Not only is it unsafe, it just looks dumb.
For the record, I drive a '04 Avalanche 2500, and tow either a 7x16 enclosed trailer (9'4" height), 5500lbs, or a open car hauler with my off-road rig on it, totaling just under 7,000lbs.
Both of these pull, turn, and stop well, as they're well within all the ratings of the truck, but I still get people asking why I bought a 2500 instead of a 1500, and run it right on the ragged edge. I only have to mention needing to perform an evasive maneuver or having to stop without trailer brakes (wire got snagged and ripped out) and see them start to "get it".
Next lesson idea - Is your drawbar/ball rated properly (With a bonus "how to select the proper drawbar")?