Is there a source to tell us how the factory determines these figures? I’m sure the tires, suspension and axles factor into GAWR, and the differential figures into the GCWR, but what other factors are included in each figure?

 

wow! are you doing a 2 million word research paper? there has to be tons of data, engineering and yrs of testing invloved.
just a sample to add to what you mention, frame design, rims, # of axles, # of tires, size of brakes, engine tq and hp, wheel base, axle end weight or corner weight, tongue weight.

could you narrow this down some? thats a big can of worms for a first post
are you two going to be hauling something? then maybe we can go over just GCWR

 

We have a 2002 Ford F350 CC DRW 7.3 PSD with a 97 gal aux tank and a 20 K reese hitch. We pull an Everest 37' 5th wheel. We have taken our rig to the Flying J scales and are well withing our GAWR and GVWR. But, we are about 1,800 lbs over our GCVWR. Our total rig is about 21,800 and we are rated at 20,000. Like everyone else out there who is overweight, ours pulls fine. We are upgrading to the Brake Smart controller as soon as they become available because we know we are pulling a heavy load and want the best at any price.

Well anyway, that is us. We are just curious as to what the manufacturers use to make those rating. When you look at the actual figures, an F250 V10 gasser will weigh a lot less than an F350 DRW PSD, but since they have the same GCVWR, that says the 250 can pull more than the 350. At least the numbers say that, but if you only look at the sience of it, you can prove that bumble bees can't fly!

By the way Ranchero, we are new to this forum, but have humdreds of posts on rv.net. We posted a similiar question there with no luck on an answer, so we decided to join this group and see if we could get a better answer here.

 

sounds like you two are allready ahead of the game. hopefully there will be some good info all can use.
1800 lbs over your GCWR may not be pushing the envelope for your spesific setup or situation but an improper balance could be unsafe.

besides the braking which you are adressing with the smart controller, you could really benifit from taking full advantage of a good weigh station. go gased up and fully loaded. by recording the weight distributed on each axle and each tire will give you some indication before running any risks. (try to be the only one at the scale for this, people tend to get ticked off when their in a hurry). for example you don't know the front tires of the working vehicle are running light and you need to panic stop while in a turn on a wet or dry road could mean trouble. the more you know about the entire rig the better you can be proactive in making adjustments in the load.

well thats my 2 1/2 cents. I hope you find all the answers your looking for here. to have an up to date topic like this is a good thing.

 

That is what we already did. We took our rig to Flying J and got weights for all 3 axles, then dropped the 5er in the lot and re-weighed both truck axles. We were all packed and gassed up for a 4 day weekend. Once we had all the axle weights we could calculate everything else: pin weight, gvw of truck and 5er.

 

This has been discussed before at FTE so a search may be in order. What I did find out personally was that with my '95 F350 Crewcab Dually 7.3PS fully loaded with gear, family and fuel, I would actually be able to haul less weight in the bed of the truck than I could with my '77 F150 4X4 with the cab loaded. That is, IF you go along with the rated weights. Towing from the receiver hitch was a different story. Those are heavy trucks and they take up a lot of the weight rating all by themselves.