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How Gross Vehicle Weight Rating (GVWR) Works

  • How Gross Vehicle Weight Rating (GVWR) Works


    A vehicle's gross vehicle weight rating is an important number to know, whether you're driving a pickup truck towing a trailer, a two-seater roadster or anything in-between. You can think of the GVWR as a weight limit for your specific vehicle -- a weight limit set by the automaker. Gross vehicle weight ratings take into account the base curb weight of the vehicle plus the weight of any optional accessories, cargo and passengers. A vehicle should never be loaded beyond the manufacturer's listed GVWR.

    Safety is the driving force behind the GVWR for any vehicle. If a vehicle is overloaded, a number of problems can result. For example, if the vehicle is too heavy, the brakes may not be substantial enough to slow down or stop the vehicle effectively; the suspension components can become ineffective or possibly even break under the added strain and tires that are overloaded generate more heat, making them more likely to blow out. For safety's sake, the GVW should never surpass the GVWR.

    It's important to understand that a vehicle's GVWR is not a measurement of how much a vehicle actually weighs. A vehicle's actual weight is the gross vehicle weight, or GVW. The two numbers should not be confused -- the GVW of a vehicle is constantly changing, but the GVWR will always remain a constant.

    Here are some links that will help you understand how all this works




    As a simple example, if a car has two passengers and one of those passengers exits the car, the GVW is reduced by the exact weight of the exiting passenger; however, the GVWR remains the same. If the same vehicle (with two passengers on board) stops to pick up a third passenger, the GVW is increased by the exact weight of the new passenger, yet once again, the GVWR remains the same.

    When you're towing a trailer, one last point to remember is that the entire weight of the trailer is not considered to be a part of your vehicle's GVW; however, the tongue weight -- the weight of the part of the trailer that actually attaches to your trailer hitch -- is part of your vehicle's GVW. Again, none of this changes your vehicle's GVWR. Trailers have their own specific gross vehicle weight ratings that, similar to the tow vehicle's GVWR should never be exceeded.

    If you're curious about your own vehicle's gross vehicle weight rating, that information can typically be found on a label inside the vehicle's door frame, often in the area where the driver's door latches. Another option is to search for the information on the Internet. Most manufacturers will publish this and other important vehicle information online.

    These rating are very important when you are building your rig. A side note: when you buy a lift kit all aftermarket regardless of how cheaply you think a certain company has made there lift kit all manufacturers have to follow these rules and manufacture their parts to the vehicle specifications so if you can buy a certain lift kit in the state or province you live in that means the manufacture of that part has passed these specifications.

    When you are adding your goodies to your vehicle make sure you don’t exceed your GVWR or else you are going to have problems with everything and most importantly problems with your suspension. Exceeding your GVWR can seriously injure yourself or worse kill you and others.

    I hope this helps everyone in you build play safe and have fun

     

    This post was edited by CrazyZJ at April 23, 2017 8:10 AM PDT
      April 21, 2017 8:26 AM PDT
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  • Thank you for the info on this gvwr stuff I had it all wrong well the info given to me was wrong. Now I'm going to have to weigh my Jeep again. I have totally revamped my Jeep with larger diffs and drive train does that make my gvwr a different rating now or am I fooling myself in thinking that?

    With what I have done to my Jeep I know it will be well over my gvwr so what do you suggest I do I can't go backwards to oem.

    Thanks again crazy zj for this writeup it is a fantastic read
      April 21, 2017 11:51 AM PDT
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  • Just a word of caution taking your rig to a government scale if they are pricks they can stop you from driving your rig home if they deem it unsafe for the provincial highways just thought I would put it out there. 

    Dam good write up CrazyZJ this is a very good description and understandable and to the point. Good on you man

      April 21, 2017 11:59 PM PDT
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  • Thank you Crazy ZJ for this write up. We all seem to forget that when we build are rigs that serious implications are in play when our rigs start to transform into what we want are rigs to be capable of. I myself have some of these problems I’m not over my GVWR but just adding 35" tires have made me address breaking issues and reconfiguration of my steering I know it is not the fault of my equipment it is the fault of adding weight which is my tires.

     

    Is there anyway of changing the GVWR in your vehicle? ( to a higher rating ) I know you are very knowledgeable in this area since you build custom rigs and racing rigs . Since GVWR plays such an important role in our rigs this thread is very important and it should be here to educate our members.

     

    Thank you again Crazy ZJ for posting this information

      April 22, 2017 8:40 AM PDT
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  • Thank you, guys, for the kudos I will address each question in order of the posts (1) Loardcrash don't feel jilted a lot of people get this wrong even looking at the internet you can get the wrong information. As for adding the larger ratted diffs to your jeep you have changed only the rating of your diffs nothing else. you may have changed your coil springs (I'm assuming your talking about your ZJ here) and steering and some other component’s but if you have not included the stiffening of your frame then your GVWR did not change you just have stronger running gear which is not a bad thing.




    (2) Willys45 you are so correct on this implications of taking your rig to a Government weigh scale. At the government weigh scale though you will get a lot more information on your weights than if you were to go to a privet scale. At the government scale if you ask them to weigh your vehicle for safety they will ask you all the information they need to give you the real information you need to work on your rig. If you feel that your rig is going to be overweight then it would be worth renting a car trailer and trailer it to your local government weigh scale. 




    After all this is one of the most important things you should look at when building your rig, it can mean the difference between life and death. We all have to use the road ways to get to where you are going to wheel that is where this can bit you. If your rig breaks on the trail not too much will happen except your pride might take a hit. 




    Safety is key one of the biggest reasons I got into custom building rigs for people is because I lost a very good friend to this very overlooked issue.



    (3) Bteck thank you and I'm glad you like the thread I know you are knowledgeable of this stuff too. 



    As for changing the GVWR to a higher rating yes it can be done. It all starts with the frame this is an argument that people do not understand if your frame is inadequate for all the new upgrades you do to your rig then all you have done is meaningless. This goes for framed and uni-body frames one is not better than the other because they have totally different characteristics and the preform differently. When you see on the internet someone trying to compare the too their argument is unsubstantiated because these too frame types are used in a total different application platform. 




    First you have to stiffen up your frame no matter what you have for a rig you have to remember that the rating of your frame is the GVWR of your rig it is no more or less. You don't see the manufacture just putting one tone frames in all of their vehicles because of costs and selling points they make the vehicle safe and as cheaply as they can.



    Once your frame is now adequately stronger after you have stiffened it you have a stronger platform to work with. Now you need to look at drivetrain Springs, Coils, Steering ext. First you have to decide what are you going to use your rig for. If you are going to Overland, Rock Crawl ext. all these applications mean you will have to either beef up your suspension with stronger springs steering ext. Overlanding you need a sturdy platform otherwise you will constantly break suspension components if you are experiencing these problems then your rig is not set up right and you are probably over your GVWR 

     

    If you are very interested in raising your GVWR it is just a matter of looking at your frame, and suspension and everything that goes with it. Yes, you are rebuilding your rig. And this is where the buck usually stops with most people they like to install all the great looking upgrades but they don’t want to do what it takes to support all the great upgrades.

     

    Here is a good analogy to get a grasp on this. You own a one-story house you want to build a second story to it what are you going to have to do to support the second story? I will leave it there for your own thoughts on the matter.


    I hope this helps. Please ask questions I can help or suggest what needs to be done. Everyone has different needs for their rig so there is no real set rule to what you have to do except you either are to heavy or not to heavy Check you GVWR and get your rig weighed then decide where to go from there if you have to.

      April 22, 2017 9:58 AM PDT
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    I’m a mechanic as well CrazyZJ it is nice to see you found a way to explain this GVWR in layman’s terms. Most of the time you ask an engineer what all this means, after it is explained you walk away just as confused as when you went in to the conversation hahaha!! Great read buddy 

      April 23, 2017 8:17 AM PDT
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  • I have a question guys all this after-market bling you can buy for these 4x4's (Jeeps) in particular do these manufactures not take into account the weight it will add to your Jeep?

      June 17, 2017 12:57 PM PDT
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  • Hi Loardcrash the answer to your question is NO It is not the responsibility of aftermarket manufactures to worry about the weight of your vehicle, they worry about the bottom dollar and how they can sell this bling to you. It is up to you as the vehicle owner to be warry of your weight.

      June 18, 2017 6:56 AM PDT
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