When my tow vehicle, a half ton truck, was manufactured it came with a sticker that displayed the GVWR. Since then I have changed and upgraded various components. Can the GVWR be adjusted for my own calculations considering these changes? For example the tires that came on the truck when the sticker was made were rated at 2,271 max load per tire. Now installed are tires that are rated at 2,833 Max load per tire. When you look at a higher tow rating for the same vehicle you find that the only change is the addition of a tow package. The gear ratio is the same, the leaf springs are the same, the engine is the same, etc. Differences include the addition of a hitch, a larger radiator and trans cooler and different tires. If you have made those same changes can you safely use a tow rating from the same truck that has had those options added?
Tow Vehicle Weight Rating Adjustment
- Thread starter BoFam
- Start date
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NO.
Only a certified vehicle alterer or modifier can change a vehicle GVWR or GAWRs.
There is nothing illegal about doing so. In fact many upgrade mods we do make the vehicle a safer vehicle when towing.
JFY....P tires capacity on a truck is required by fed regs for its capacity to be derated by dividing its capacity by 1.1...so that 2833 lb rated P tire now has 2575 lb capacity.
Without doing a lot of dig work don't assume adding some type of upgrade will equal the mfg upgrade. Example is Fords F150 has over 11 different GVWR packages...3 different RAWR packages and three truck frame thicknesses and dimensions.
Do your home work and the truck will do fine.
Gary RV_Wizard
Site Team
Ditto what longhaul says.
As a private owner, you are not limited by the official GVWR, GAWR or GCWR ratings shown on the federal placards (commercial user are). However, I would keep records of my capacity upgrades just in case I was ever challenged in court with a civil damage lawsuit after some future accident that might somehow be related.
As a private owner, you are not limited by the official GVWR, GAWR or GCWR ratings shown on the federal placards (commercial user are). However, I would keep records of my capacity upgrades just in case I was ever challenged in court with a civil damage lawsuit after some future accident that might somehow be related.
I thought about making this statement first, but didn't for some reason. I ask because I want to tow safely.
I do not want to print my own sticker compromise the vehicle in any way.
Where do you go to find the information that would help me with my homework?
I do not want to print my own sticker compromise the vehicle in any way.
Where do you go to find the information that would help me with my homework?
Rob&Deryl
Well-known member
BoFam said:
Several ratings are involved in towing. The tow rating mostly is involved with pulling and stopping. Imagine a flat deck trailer with a load of bricks. You need a certain amount of power to get it rolling up to highway speed and sufficient brakes to stop it. The tow package comes in when you want to haul those bricks, for example, from Denver to Glenwood Springs. Not only do you need the power to get that trailer up the hill but you need to keep the engine & transmission cool with that load over the many mile upgrade and engine braking via lower transmission gear on the down grade. Those are what the tow rating is for. It does not account for the big front of a camper pushing against the air at highway speeds. Most manufacturers have a guide that provides deratings when towing an rv trailer.
Next are ratings about load carrying capacities. Your drivers door latch post has a yellow bordered sticker with the max cargo capacity. This number has to account for passengers, pets, tools, the tongue or pin weight of a trailer etc.
It is based on many factors including tire, wheel, axel and spring capacities.
For example, if you changed tires to higher weight carrying capacity but have exceeded the wheel (rim) rating, you are still limited by the wheel rating. If you replace the wheels with higher rated ones, you may be exceeding the axel rating. Upgrading the axel may exceed the rating of the springs or their mounts.
I hope this helps.
Gary RV_Wizard
Site Team
Nothing you could print on a sticker of your own would have any validity, so don't bother. On the other hand, it can't compromise anything either, since it has no legal standing at all. As long as you don't imitate or forge the federal weight placard, that is.
What sort of homework do you want to do? As previously stated, only a certified chassis or chassis component builder can issue new official ratings (GVWR, GAWR, etc).
Much of the upgrade stuff you mentioned is mostly about mitigating wear & tear on the vehicle. As the tow load increases, the components that may have lasted 20+ years might get shortened to 3 or 5 or 15 years. Tires, brakes, drive shaft joints, rear axles, etc. all get more stress. The engine and tranny run hotter, so that takes a toll too. A chassis engineer analyzes all the loads on all the components and makes an assessment of the weakest links and comes up with a reasonable limit for the loads.
Gary RV_Wizard
Site Team
It sounds as though you have probably improved the truck enough to be able to carry more payload. That may be sufficient to carry more gear in the bed or handle a greater trailer tongue weight (subject to the hitch capacity). If that was your objective, you are probably safe enough and won't damage the truck. The cooling system improvement may also enable more towing capacity. Your comparison to a factory-upfitted truck is probably as good as you can do.
The risk is that you have not noticed some other changes the factory makes.
The risk is that you have not noticed some other changes the factory makes.
John From Detroit
Well-known member
What componets did you upgrade?
GVWR and CGVWR are based on axle strength. Brakes. Suspension, Frame and more.
The only safe way to upgrade the weight ratings is trade it in on a bigger truck.
GVWR and CGVWR are based on axle strength. Brakes. Suspension, Frame and more.
The only safe way to upgrade the weight ratings is trade it in on a bigger truck.
rbrdriver
Well-known member
A couple of years ago I "upgraded" my 2500 Ram by going to a Ram dealer and trading it in for a Ram 3500 dually...... 8) 
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old_toys
Well-known member
I always though there is a world of difference between wow I can pull another 1000lbs and safely pulling another 1000lbs. is the truck able to handle the load if the brake controller quits working. I've had that happen.
steveblonde
Well-known member
nothing with change the GVWR or the payload just cause you add airbags it doesnt change a thing other than the truck is more level. same with the tires they are just better tires again with the brakes - they are just better brakes. you want more capabilty buy a new truck like a 2500 or 3500 series
