GVWR

[norskeman]

2004 2500HD has a GVWR of 9,200 lbs.

The front axle has a GAWR of 4670 lbs and the rear axle has a GAWR rating of 6,084 lbs. Front spring capacity is 4800 lbs and the rear spring capacity is 6084 lbs.

So why isn't the GVWR greater than 9,200 lbs?



2004 GMC 2500HD EC LB D/A; GMC bed liner;Michelin LT265/75-R16;Luverne Running boards; Bilstein shocks; Delvac 1300; Isspro gauges.

Towing a 2004 Everest 291L 5th wheel

[tanker]

Thats a great question. GAWR is Gross axle weight rating, which is the most amount of weight that you can carry on that axle. GVWR is Gross vehicle weight rating, which is the most amount of weight that you can carry on the complete vehicle. You have a front GAWR of 4670#, and a rear GAWR of 6084#, and a GVWR of 9200#. What that means is you may load the rear with cargo, but not exceed 6084# on that axle, or possibly a snowplow mounted up front, but do not exceed the 4670# on the front axle. Now the GVWR is the vehicle's ability to carry (not tow)9200# total. Why you ask? Well its always the weak link in the chain, which in this case could be the frame, or brakes, square inch of tread upon the road surface, or any number of things that the manufacturer has determined is a weak link in the chain. Now weigh your vehicle empty, w/full tank of fuel and driver, subtract that from the 9200# GVWR and that will give you how much you can load your truck. Iguess this is not the answer you really wanted, but thats about it. Spring ratings most always exceed axle ratings, which is good for when you may overload, as everyone has done once in a while. Also weight ratings are also figured at highway speeds, so some axle manufacturer's will derate axle's by speed. One example is a company that has a 26,000# rear axle, will increase the rating to 30,000# if the top speed is limited to under 25mph. say for off highway use. ie; airport refuelers etc. smile.gif

[biker Wayne]

Tanker said it right. Here is some additional info. The rear GAWR is 6084. If you look at your stock 245R75x16 Steeltex tires, you will see a max load of 3042 pounds at 80 PSI. With 2 tires on the rear axle, you get a total of 6084 (3042 times 2). So the rear GAWR is based upon the max load of the 2 tires. If you upgrade to 265R75x16 tires with a max load of 3450 pounds, guess what? You can essentially haul 6900 pounds on the rear axle if the springs will hold it (they won't). Adding air bags (or additional leaf springs to each spring pack) will essentially allow you to haul more weight in the bed of the truck. You will probably go over the GVWR of the truck, but if you keep the load under the front and rear GAWR, you should be allright. Some people argue about not going over the GVWR, and there is some concern about DOT, but the only difference between the new 3500 SRW and a 2500 HD is the tires (265R75x16) and 2 more leaf springs in a third phase overload spring pack. Guess what the GVWR of the 3500 SRW is? Its 9900 pounds. The following are EXACTLY the same on a 2500 HD as on a 3500 1 ton dually: differential, axle, brakes, frame and front end suspension. The differences are 4 rear tires on the dually versus 2 on the 2500HD and 3 additional overload springs on the dually. The dually has a GVWR of 11,400 pounds.
Its also interesting to know that the GCWR (gross combined weight rating) of a 2500HD or 3500 dually is 22,000 pounds. Guess what the parking prawl of the transmission is rated at? You guessed it, 22000 pounds. So the GCWR is based upon the parking prawl, not engine, trans, brakes, frame, suspension or axles. I've heard of guys pulling up to 25,000 or 30,000 pound gooseneck trailers with no problems. Do I advise it, no. You have to do your own research and make your own decisions. Its your truck and your life.
Hope this adds some light.

[norskeman]

Tanker & Biker Wayne - thanks for the info.

Will be adding a set of Air Lift Super Duty air bags this weekend. They should take a little load off the shocks and springs. Should also help "flatten" out the ride when towing a 5th wheel.

All in all I figure that the MODs I have made to the suspension and tires will improve the overall stability of the 2500HD when pulling my 5th wheel.

[tanker]

I also have the air spring helpers, make sure you isolate right and left side so that they won't push air to the opposite side when leaning in corners. I have an onboard air compressor w/tank and use two adjustable regulators and a dual-needle (truck style)air pressure gauge. I can adjust the amount of air I need from the drivers seat. I run about 20-25 lb when empty, and increase it for various loads, will not bottom out, and gives a smoother ride when loaded. smile.gif

[jcummins]

I have an air lift system, and wouldn't do without it. But...I do have a question about isolation of each side. I get a slight lift on the passenger side, and I

[jcummins]

I have an air lift system, and wouldn't do without it. But...I do have a question about isolation of each side. I get a slight lift on the passenger side, and I

[tanker]

To isolate each side, it must be independent. ie; one air line to each bag (spring) from its source. As I stated above I have an individual 1/4" air line running from each air bag (spring) to an adjustable air regulator in the cabin. (two (2) regulators & two (2) gauges) That is the only way you can put the same or different pressure in each air bag (spring). I used an air pressure gauge with two (2) needles, the same as used in many earlier air brake trucks, for space reasons. Hope this helps with your questions. smile.gif

[GA-DMAX]

I beg to differ about the only difference between a 2500HD and a #3500 being the springs. Take a close look. The drive shaft is substantialy bigger and the differential housing is much bigger ( even though its also 14 bolt ). I assume the ring and pinion are also heavier duty. The axles are heavier and the hubs that the wheels mount to are larger in diameter. 2500 rims will not fit a 3500SRW.

[Colorado Kid]

GA I think you must have been looking at a 2500HD with the 6.0L gas engine. The 6.0s have the 10.5" ring 14 bolt, but the 8.1L and Dmax have the 11.5" 14 bolt, same as the 3500SRW and 3500 DRW. The 3500SRW does use wheels 1/2" wider, to accomodate the 265/75R16 tires with a wheel of the recommended width, but I'm pretty sure the wheels could be interchanged with ANY 2500HD.

Some D-max 2500HDs have smaller diameter 2-piece driveshafts with a carrier, and some have HUGE diameter single piece shafts without a carrier. The 6.0s may have an even smaller diameter driveshaft that the 2-piece Dmax for all I know.

As near as I can tell the only difference between a 3500 SRW and a similar (as in D_max, Longbed)2500HD is tires (265 vs 245), wheels (7" vs 6.5"), springs (3 stage vs 2 stage), door pillar sticker and (at least on GMCs) the numbers on outside of the door.

Another difference is that by town ordinance my 2500HD can be parked on the street in front of my house but the 3500 SRW can't. (No trucks heavier than 3/4 ton). :rolleyes:

[Wont Goof Again]

I have been reading this thread with great interest... I currently own a 2002 Silverado 4x4 D/A Crew Cab Long Box - the heaviest 3/4 ton that you can buy. It weighs in at 7400 lbs (includes me in the truck, 2/3 tank of diesel, a Leer 122 cap, and a few tools in the back); 4290 on the front axle, 3110 on the rear.

I am looking at replacing our current travel trailer with a 5th wheel, but am having some problem understanding the consequences of going over the GVWR. The trailer we are looking at purchasing has a dry pin weight of 1500 pounds, so the wet weight will most likely be in the 1800 - 2000 pound range.

If I remove the cap and replace it with a 5th wheel hitch, the truck's weight will probably remain about the same. Add the wife and kids, a full tank of diesel, and this particular 5'ver and I'm looking at around 4500 front, 5000 rear, total 9500.

What problems am I looking at if I purchase this trailer? Will I need upgraded springs on the rear? Do I really need a 3500? Anything else...?

BTW, we usually tow around 3000 - 8000 miles per season (from May - Sept).

[ 03-13-2004, 03:56 AM: Message edited by: Wont Goof Again ]

[tanker]

Won't Goof, You should be fine from what I see. You will be ok on axle weight and about 300lbs over on gross. And this is only an estimate, I sure you could pin this down to a closer estimate. Most manufacturer's are concervative on their numbers, and I don't know what GM's fudge factor is. I think their are a lot that are running over on gross weight, including me. :rolleyes: If you had dual rear wheels you would be fine, and under by a many pounds. smile.gif