Payload Capacity & Max Tongue Weight: Help me understand

Information overload:

This is what you want to do and will cost you some money unless you know someone that has access to a scale. Fortunately for me, I have a CAT certified scale at work. High Five myself. Another way is pull into a DOT checkpoint, park, and then go in and ask nicely if you can use the scale to get some weight rating numbers. Do this empty, empty with trailer, and trailer loaded. If you have any questions a DOT officer should know (but not always). Do not try to disconnect at a DOT inspection station unless they say it is ok to do so.

Before wasting a lot of time, energy, and money the vehicle owner should know some ballpark numbers. I will use my truck/trailer combo. Plug in your numbers as needed:

-Gross Combined Vehicle Weight Rating 25300 lbs
-Gross Vehicle Weight Rating 11500 lbs.
-Vehicle Capacity Rating (payload) 3808 lbs. This will be inside the drivers door jam stickers.
-Vehicle Hitch Rating and Load Distribution Hitch rating. 1200 lbs convention without LDH/1500 lbs with LDH. Owners manual/on hitch.
-Gross Trailer Weight Rating 16000 lbs. On trailer faceplate. My truck is rated to pull 17200 lbs if everything in the load calculations work out.
-Front/rear axle weight ratings. Rear 7050 lbs/front 5600 lbs. Owners Manual.
For ease of things, I know my truck rear axle weight is 3200 lbs and front axle is 4400 lbs (I think my front axle is right. I would have to check my notes). So does this mean I can put 3850 lbs in my bed and be good? No. This is when checking the information in the drivers door jam is useful. Mine is 3808 lbs. There is a little fudge factor of course (42 lbs), but I like to use the lower number even though the capacity and actual weight says otherwise.

Now, can my vehicle tow or load what I want to? If the answer is yes…continue.

Take your vehicle to the scale. Now drive the front axle on the scale, record that number. This is your empty front axle weight. Now pull onto the scale. Record that number. This is your empty vehicle weight. Now pull the vehicle front axle off the scale. This is your rear axle empty weight.

Now go get your trailer. For you camper guys, load the trailer up as if you were going camping. I know, PITA. Now go do it or no soup for you!

As you are pulling on scales, record front axle weight. Then pull on the scale record that weight. When pulling off the scale stop short to get the rear axle weight loaded.

Combined weight. Now I know what my truck and trailer weight together. This setup can legally tow 25300 lbs. I can put 12,870 lbs on my trailer/truck combo. 25300-12540=12870 lbs



Next you want to get just the trailer weight. Pull forward to when the jacks are out down, the weight of the trailer are still on the scale. Having hydraulic jacks is nice. Just wanna toss that in there.

My trailer empty weight is 4600 lbs. This particular trailer has a 16000 lb rating. Can I just put 15000 lbs on this trailer with this truck? No. Get into that later.



Without moving, hook the trailer back up. This is your empty hitch/pin weight.
4600-3560=1040lbs empty pin. This number is important on figuring out tongue weight for conventional towing or pin weight for 5th wheel/gooseneck hitches. 4600x.225%=1035 lbs. Close enough. As most 5th wheel/GN trailers are set up, 22.5% of the trailers weight is transferred to the truck. This is why buying GN trailer for a 1/2 ton is not a good idea. Conventional trailers are 9-15% tongue weight normally, but not always. Now I also just added 1040 lbs to the axles. A small portion goes to the front and the majority is on the rear axle.

For ease of this discussion, we can estimate 900 lbs went to the rear and 140 lbs went to the front. 4600+140=4740 lbs. 3200+900=4100 lbs. Good to go.



Now you know what your empty weights are, time to go load up and repeat the process. This is when you can make adjustments to the load (positioning) within reason. This is also the time to see how a load distribution hitch is working. If the hitch hasn’t distributed enough weight, pull off scale, make adjustments, weigh again.

So what do all these numbers mean? Let’s cover that.

Gross Combined Vehicle Weight Rating GCVWR. As stated earlier, my truck is rated for 25300 lbs truck and trailer combination. Can I go over this with my setup? Absolutely. 11500+16000=27500 lbs. if I was in commerce, I would get fined even if I was under 25300 lbs. The officer goes off what the truck/trailer is rated for. If I were ever deemed in commerce/commercial, an overweight ticket could be issued. I have been ticketed before. I think it was for every 1000 lbs= 20.00. The commercial truck I was driving before putting anything on it was overweight by 2500 lbs from the get go. If I loaded up a couple transformers and three electric line poles the fines can add up quickly.

Gross Vehicle Weight Rating. Mine is 11500 lbs. All this means is total loaded vehicle weight (trailer pin weight, all passengers, any vehicle mods, cargo, etc)

Tongue weight/Hitch weight rating. Some manufactures do not put a "rating" on the vehicle. You need to find out what class hitch you have. Typically there is a rating. Mine is 1500 lbs. Some are different rated if using a LDH.

Payload. Mine is 3808 lbs. This means I cannot exceed this due to tongue/pin weight and passengers. Let's say my family weighs in at 608 lbs with dog. That means I can load a pallet of concrete in the bed if it doesn't exceed 3200 lbs. Following this number also helps keep the axle/tire ratings under maximum. Remember earlier, my truck has a rear axle capacity of 7050 lbs. If I put 3808 lbs in the bed (including passengers). I already know my rear axle weight empty is 3200 lbs. So 3200+3808=7008 lbs. Now let's talk about tires for a second. Not all tires are created equal. A Load Range E tire has a pretty wide range depending on size and different air pressure ratings. We need to look at Load Index. For my truck, I require a Load Index of 124.



So my tire ratings are 3527 lbs each. 3527x4=14108 lbs. Tires exceed GVWR of 11500 lbs. I should be good to go and have lots of extra capacity right? Not so fast. 3527x2=7054. Remember that rear axle rating of 7050 lbs? If I am even a few pounds overloaded I can exceed the tires maximum weight rating. This is why when members say "the Tundra is more of a 3/4 ton. It can handle a lot more than advertised" makes me shake my head. You sure about that? Can the AAM 11.5" rear axle take more weight than that? Yes it can in different applications. My tires are the limiting factor in this equation.

https://www.discounttire.com/learn/load-range-load-index

Gross trailer weight rating. This is a two part. You have a GCWR as well. So mine is 25300 lbs. I can safely tow 5th/GN 17200 lbs. My trailer is rated at 16000 lbs. Trailer weight is 4600 lbs. My pin weight is 22.5% of trailer weight. So if I maxed out the trailer of 16000 lbs, my pin weight will be ~3600 lbs. So I can put myself in the cab and better take a crap before I leave. Be cutting it really close on that one. Well how can I have a 17200 lb rating for a trailer. Well not all trailers are loaded at 22.5% pin weight and sometimes people pull doubles. Not suggesting that is a good idea. Now remember my truck is also rated at 11500 lbs. So 11500+16000=27500. So if my truck/trailer is ever at maximum capacity, I could be overloaded by a lot.
My Tundra had a 16000 lb Combined rating and a 9000 lb tow rating. 7200 GVWR + 9000 lb trailer=16200 lbs (toyota reduced to 16000 lbs).

Hope this helps a bit. I have to take the kiddo's to school, so I will clean this up a little later.

 

Thanks fellas. I guess being at home on crutches has site benefits..

I will try and copy/move this to the stickied towing thread. Hope this helps people out with the what and why's.

 

https://www.tundras.com/threads/tow-ratings-guide-how-to-be-safe.39211/

Also in the tow ratings guide, how to be safe thread.