How important is GVWR?

[RoyJ]

We all know the rules regarding GVWR, but how many of us ACTUALLY follow it (with weight tickets to prove it)?

Modern Tacomas can have as little as 950 lbs of payload. Front and rear armour / bumper, sliders, skids, winch, drawer, RTT, big tires, jerry cans, batteries, fridge, and you're left with 150 lbs for passenger... My old LX 470 was no better - 1350 lbs payload with the 3rd row removed, and absolutely stock.

If we follow the rules to the letter, big tires, aftermarket suspension, heck, even brake pads with lower than OEM friciton code, and you instantly void your GAWRs (and by relation, your GVWR). No factory OEM engineer would defend you in a court case once you lift your truck - all GVWRs goes out the window.

In reality, have we heard of ANY real life cases where the insurance corporation went that far?

 

[s.e.charles]

We all know the rules regarding GVWR, but how many of us ACTUALLY follow it ….

if your doctor tells you to modify your behavior or else your health is at risk, how many of us do it? does your life insurance still pay off?

who's the winner ?

 

[RoyJ]

if your doctor tells you to modify your behavior or else your health is at risk, how many of us do it? does your life insurance still pay off?

who's the winner ?

How do you define a "win"?

If we all sat home, drank green smoothie, ate chicken breast, and ran on a treadmill - then drive a bone stock Corolla to the store to refill your green veggies. You'd live a long life. A long boring life. Win?

Every "fun" in life has its risks and associated cost. Drive 51 in a 50 zone? You're breaking the law and there's a risk and cost. There is no clear cut "win".

 

[DaveInDenver]

You're breaking the law and there's a risk and cost.

There's no law in Colorado (couldn't say for every location) that requires an individual non-commercial driver of a vehicle under 26,000 lbs GVWR to adhere to any weight restrictions.

Despite being perfectly legal being overweight it is much more of an assumed risk than driving above an arbitrary speed limit that set based on unrealistic handling assumptions easily exceeded by the majority of vehicles on the road. There's legal and there's reasonable, never (rarely) the twain shall meet.

I'm one that tends to see GVWR as important and tries to stick to it. But as has been mentioned it's very difficult to do so. The problem I have is that no manufacturer is going to explicitly tell you how they arrived at it, what criteria they used. Is it simply frame deflection, spring rate and brake sizes? Maybe. Handling and propensity to tip? Maybe. The upfitting guides suggest how a GVWR might be calculated for a cab-and-chassis, for example. But we can only infer that Toyota (as an example) rates their vehicles with margin that improving the suspension and reinforcing the frame and bed walls is *probably* a safe thing to let you carry more than the door tag says you can. But that holds no legal justification for liability.

 

[s.e.charles]

well … I ran out of kale & soy-dingles for my sunday morning smoothie, so I went on an overlanding expedition to the farmers market 8.04672 clicks (5 miles for you non-explorers) S x SSW away. I wasn't going to wear my Tilley hat, but I thought the sun might break through the cloud cover before my return, so I took it, and my photographers vest with the custom added epaulets.

not wanting the kale to wilt in the event I had to do any winching on the ride home, I brought the small yeti cooler. I felt no need to use the refrigerator for such a specialized task, and with no sun the solar array may have had a challenge to keep up anyway.

evidently since my last visit (memorial day - grande 2018 opening day) some of the vendors had been moved around. fortunately, in pocket #19 of my vest I had my lensatic compass. the app I had downloaded to my smart phone told me right which pocket to look in so there would be no fumbling.

so I get to the kale table, and lo & behold, the most beautiful creature I have ever seen. her name was Krystal, yes, with a K, and her long, fire red, dreadlocks absolutely made the lush green kale pale by comparison. I stammered something about risky behavior, kind of smiled, but it was really a wince, and she filled my bag to the brim with her bounty.

all the way home, I felt I had a clear cut "win".

and the next morning?





Krystal's Kale Revenge!!!!


you want life on the edge? drink 3 kale smoothies in a row. . .

 

[rruff]

A FWC Fleet with basic extras (hot water heater, furnace, compressor fridge, solar, 2nd battery) weighs around 1,300 lbs empty. A double cab Tacoma has a payload of around 1,100 lbs. Add 2 people, equipment, a full water tank, propane, ... and you're potentially 700-800 lbs over the Tacoma's GVWR. But yet, FWC advertises their Fleet specifically for mid-size trucks like the Tacoma, Frontier or Colorado, well knowing that most customers will be over GVWR. Most dealers simply say "add a leaf and you're good". That may work for weekend campers but for true overlanding ... ? As if the extra leaf will fix all the other issues like brakes, frame, etc.

Good synopsis. Nearly all 1/2 ton trucks with a camper on are over GVWR. Some are over by a *lot*. I see plenty of Tundras with campers that are 2x the payload. With proper suspension and tire upgrades these are not dangerous in any sense (braking and handling) compared to towing a 10k lb trailer, or all the other big trucks and RVs on the road.

Can anyone point to what GVWR is actually based on and what it means?

 

[carbon60]

I always thought that it was more important to stay within the gross axle weight rating (GAWR), thinking that the brakes were probably factored into that. Suspension is simple to upgrade, brakes are usually not.

 

[rruff]

I don't think the axle rating has anything to do with brakes, rather it's the axles, suspension, and tires. The total GVWR might have something to do with brakes, but in reality there doesn't seem to be any kind of "standard" being tested.

 

[DaveInDenver]

The upfitter GVWR formulas for incomplete vehicles seems to be based on front and rear gross axle weight along with wheelbase, vehicle center of gravity and center of payload mass relative to the axles.

But I don't know precisely how it's determined by the manufacturer on a complete vehicle. Obviously there's a handling aspect to the GVWR since they are concerned with where the weight is located. Even the camper data in the owner's manuals say this explicitly, though.

That's why I can't judge someone who goes over GVWR is or isn't unsafe. Pound-for-pound it would seem perhaps that a rear swing out bumper with spares and fuel hung a mile back and a winch bumper are probably worse than centering a camper, sliders and an oversized fuel tank located between the axles.

 

[RoyJ]

I don't think the axle rating has anything to do with brakes, rather it's the axles, suspension, and tires. The total GVWR might have something to do with brakes, but in reality there doesn't seem to be any kind of "standard" being tested.

The axle rating from the axle manufacturer itself (AAM, Meritor, etc.) factors in the bearing / housing loads as well as brakes (if it comes with one).

The rating from the OEM, which often is lower, factors in suspension + tires as well. The final GAWR out of the factory factors in all braking, suspension, and tire specs.

This is why I said earlier, the minute we slap on larger tires, taller suspension, or lower coefficient brake pads, all ratings goes out the window.

 

[RoyJ]

There's no law in Colorado (couldn't say for every location) that requires an individual non-commercial driver of a vehicle under 26,000 lbs GVWR to adhere to any weight restrictions.

Despite being perfectly legal being overweight it is much more of an assumed risk than driving above an arbitrary speed limit that set based on unrealistic handling assumptions easily exceeded by the majority of vehicles on the road. There's legal and there's reasonable, never (rarely) the twain shall meet.

I'm one that tends to see GVWR as important and tries to stick to it. But as has been mentioned it's very difficult to do so. The problem I have is that no manufacturer is going to explicitly tell you how they arrived at it, what criteria they used. Is it simply frame deflection, spring rate and brake sizes? Maybe. Handling and propensity to tip? Maybe. The upfitting guides suggest how a GVWR might be calculated for a cab-and-chassis, for example. But we can only infer that Toyota (as an example) rates their vehicles with margin that improving the suspension and reinforcing the frame and bed walls is *probably* a safe thing to let you carry more than the door tag says you can. But that holds no legal justification for liability.

If you want my take on this - the axle manufacturer GAWRs are a hard limit that I do not exceed.

Why? It has the least, if not zero, marketing built it. It's also unaffected by suspension choice from the factory.

I also have a problem of how manufacturers arrive at their GVWRs, and I think it's mostly marketing / law, with little engineering. Take the Power Wagon for instance, it has the same frame, axles, brakes, as a Ram 3500, yet with less than 1/2 the payload, and about 1/2 the towing capacity. So if I upgrade the suspension, how is it NOT safe to exceed factory GVWR?

However, no matter how many air bags I put on, the hard limit set by AAM for the 11.5" axle (somewhere around 10k lbs) cannot be exceeded.

In the DOT world, GVW always equal sum of GAWRs. Straightforward, no marketing, no legal.

 

[carbon60]

In the DOT world, GVW always equal sum of GAWRs. Straightforward, no marketing, no legal.

This is what I was told by a Transport Canada guy, as well.

 

[Bayou Boy]

There's a reason a new Ram HD build thread pops up in the Domestic Forum every week. This thread is that reason.

 

[DaveInDenver]

So if I upgrade the suspension, how is it NOT safe to exceed factory GVWR?

Agreed on your points. I'll only add that when you consider center of gravity and maybe Ram is factoring in use and the case where the smaller load is carried higher on secondary roads where being top heavy would be a bigger problem. Even if this is not something the manufacturer considers it seems like something the end user should.

IOW, when comparing a PW to a 3500, when equipped comparably, they would both be safe with the same load in the same conditions. So is it possible the GVWR on the 3500 should be adjusted *down* if it was taken on the same trails?

The only evidence I can cite is that trucks often have much larger tow ratings and my presumption is this is because it's safer being low and generally would need to be on pavement.

 

[Bayou Boy]

Agreed on your points. I'll only add that when you consider center of gravity and maybe Ram is factoring in use and the case where the smaller load is carried higher on secondary roads where being top heavy would be a bigger problem. Even if this is not something the manufacturer considers it seems like something the end user should.

IOW, when comparing a PW to a 3500, when equipped comparably, they would both be safe with the same load in the same conditions. So is it possible the GVWR on the 3500 should be adjusted *down* if it was taken on the same trails?

The only evidence I can cite is that trucks often have much larger tow ratings and my presumption is this is because it's safer being low and generally would need to be on pavement.

The Powerwagon GVWR is low due to tires and soft springs. Thats it. I have a friend that went from a 2500 4wd Cummins to a Powerwagon. He was comfortable pulling his 36 Yellowfin with the regular 2500 but the suspension of the PW is just not up to the task and he borrows a work truck when he needs to pull it now.