Improving Tow Capabuilty

[MChrist]

Harvey, I agree. With nobody in Illinois having any clue regarding what I'm talking about, I will have to assume that it's not realistic to have a 2500 recertified as a 3500 with proper parts. Must be an urban legend. And if it's possible, it's probably a huge can of worms not worthy anybody's time.
While searching for answers, I ran across an engineer for GM who's job had to do with tow ratings for their trucks. Among several requirements they had, one was that they had to be able to climb a 25% grade from a dead stop at max GCVW. Another was that the trans in park (or parking brake) had to hold that load on the same hill. Makes me wonder if those requirements are GM only or across the board...
If accurate, that would help to explain how manufacturers determine how much to raise tow ratings based on only a rear gear ratio change. I always wondered how those numbers were determined... ...

 

[HBarlow]

Harvey, I agree. With nobody in Illinois having any clue regarding what I'm talking about, I will have to assume that it's not realistic to have a 2500 recertified as a 3500 with proper parts. Must be an urban legend. And if it's possible, it's probably a huge can of worms not worthy anybody's time.
While searching for answers, I ran across an engineer for GM who's job had to do with tow ratings for their trucks. Among several requirements they had, one was that they had to be able to climb a 25% grade from a dead stop at max GCVW. Another was that the trans in park (or parking brake) had to hold that load on the same hill. Makes me wonder if those requirements are GM only or across the board...
If accurate, that would help to explain how manufacturers determine how much to raise tow ratings based on only a rear gear ratio change. I always wondered how those numbers were determined... ...

That's the first information on method of establishing GCWR I've heard that was actually sourced from a guy who was involved in doing it. I'm sure that GM, Furd, and Ram all have similar but different engineering guidelines for determining their truck's GCWRs that include those you mentioned.

I've tried to explain the fundamentals that I could envision would have to be considered in previous discussions but I was only guessing. I'm sure that ability of the cooling system to maintain the engine and transmission within a reasonable operating temp range would be included as well.

The bottom line with your truck, as I see it, is this: 1) You won't be commercial so you are not likely to be required to scale weigh or undergo commercial truck inspections 2) If you don't overload the combined weight carrying capacity of your rear tires (be they OEM or upgraded 19. 5" wheels and tires), and 3) if your truck is not sagging at the rear and lifting the headlights into the trees at the front, you should be okay to tow a larger trailer.

I have said repeatedly here and some refuse to understand or accept it, the factory GCWR and factory maximum trailer weight ratings are based on engineering considerations based on driveline torque handling capability, cooling system limits, minimum startability and acceleration rates, not enforceable law.

DOT cops don't know or care what your GCWR is or what Ram said you can tow. If your truck and trailer combo are registered and licensed for their actual weights, and if your kingpin weight or trailer tongue weight on the ball don't overload the rear axle carrying capacity determined by your tires, you will be meeting MINIMUM requirements.

Having said that, I personally would not tow a heavy trailer without a BrakeSmart or MaxBrake controller, an exhaust brake, and a good load safety margin on my tires.

 

[AH64ID]

Ya, thats the ticket (no pun intended) if towing for recreation then you should be fine but I wouldn't do it, if its for commercial.

That is an excellent point that I hadn't thought about, was simply thinking RVs. But it no means would I try to upfit a lower rated truck for commercial use, whole different set of rules and cops.

My tires at 80psi will handle 3990lbs per tire.

But what are your wheels rated for? I can buy tires that have over 500lbs more rating than my OE tires, but I am still on the same wheels. They are equeally as important.

I have said repeatedly here and some refuse to understand or accept it, the factory GCWR and factory maximum trailer weight ratings are based on engineering considerations based on driveline torque handling capability, cooling system limits, minimum startability and acceleration rates, not enforceable law.



DOT cops don't know or care what your GCWR is or what Ram said you can tow. If your truck and trailer combo are registered and licensed for their actual weights, and if your kingpin weight or trailer tongue weight on the ball don't overload the rear axle carrying capacity determined by your tires, you will be meeting MINIMUM requirements.

Exactly. A 2500 can accelerate and brake the same weight at the same rate as a DRW 3500. A 2500 is simply rated lower than a SRW 3500 because it has to be, why make two models to rate them the same? Just load it smartly understanding how to load it, where the weight balanace is, and what your weights are and you will be fine.

 

[RustyJC]

Although the establishment of GCWR and fictitious "trailer tow ratings" has turned into a marketing game today, a number of years ago it wasn't unusual to see all kinds of vehicles in the Davis Mountains of West Texas in the summertime undergoing testing by the manufacturers. These would include pickups with loaded gooseneck or box trailers with the vehicles instrumented to the hilt. I'm sure they were testing for overheating of the cooling systems, transmissions, and rear axles, ability to achieve/maintain speed up a specified grade and other technical considerations the manufacturers evaluated in establishing vehicle ratings.



I'm afraid that today we're seeing more of an approach of "our competitor has a 25,000 GCWR, so let's up ours to 25,500". HERE is a detailed description of SAE J2807 that may bring some reality back into the ratings game.



Rusty

 

[HBarlow]

It would have been very interesting to have been able to observe the Texas summertime testing in the Davis Mountains.

I can't remember what brand it was now but several years ago I saw a fleet of light trucks with MI MFR plates in convoy on an interstate highway pulling trailers. You couldn't miss all the additional instrumentation festooning their dashes.

I saw Cummins, Inc. engineers and techs testing the new HPCR/Gen III trucks out of the MREP at Columbus, IN during the big TDR rally held there in July 2002. They were running several new Ram trucks around the clock to hit 100,000 miles before the new trucks (not the ones undergoing testing) were shipped to dealers. The trailers they were pulling had large sheets of plexiglas mounted across the front to create wind drag and dead weight loads on the trailers to reach maximum GCWR/max tow weights. Would have loved to have ridden a shift with them.

I am pleased about the new SAE J2807 you referenced. If light truck manufacturers are required by federal law to comply with those standard the vast towing advantages claimed by Furd and GM will likely vanish without further mention like a politician's campaign promises.

 

[Road Dog]

A friend of mine "recertified" his GM 3/4T by replacing the "2500" decals on the door with "3500".

 

[meanmatt]

I would see if the dealer lets you hook up the trailer to your truck . Then take a good look at it . Look at the sqwat ,look at the frontal area . Now be honest with your self. Ask yourself if you would just hop in the drivers seat and head cross country ? Or I need to mod this or that ?Or this will be okay because my favorite camp spot isn't very far away. I have walked away from many campers because it just didn't look like it would work with the truck . Trust the hairs on the back of your neck.

 

[AH64ID]

A friend of mine "recertified" his GM 3/4T by replacing the "2500" decals on the door with "3500".

But the door badges aren't what will be looked at, only the door placard.

 

[MChrist]

... I think Road Dog was kidding...

 

[AH64ID]

... I think Road Dog was kidding...

I'm 99. 9999% certain of it. . just throwing it out there for someone who may not realize it.

 

[HBarlow]

A friend of mine "recertified" his GM 3/4T by replacing the "2500" decals on the door with "3500".

Good plan. His badge re-engineering was no different than the brochure engineering done by Furd and GM to reach those huge gross combined and trailer towing weights they publish.

 

[Road Dog]

But the door badges aren't what will be looked at, only the door placard.

Usually they (commercial vehicle inspectors) start with a visual and if it looks good (clean, not squatting, no ghetto mods) then off you go. There's no time to check all the vehicles going by.

 

[Bob Cochran]

Does this fall into the same category as in the old days running odometer backwards with a drill motor? :-laf

A friend of mine "recertified" his GM 3/4T by replacing the "2500" decals on the door with "3500".

 

[bromano676]

ok so I got a little tired of reading all the posts. But I think I get it.



Here is my . 02 cents. If anyone cares. When I bought my truck it was registered at 8800 pounds. Rated to tow, in the dodge manual, 13,000pounds give or take a few.



The auto version was something like 8500 towing capacity. Thinking here, it was the transmission that derated it.



In an effort to pay less money is various situations, I went to DMV to re-register and asked the lady behind the counter if I could lower the registered weight. She looked it up in the computer and said that the average 2500 series truck was registered between this an that ( sorry I do not remember the exact numbers). So I could register it anywhere in between that. So I registered at a few pounds lighter then 8800 and have been there ever since.



Now, I know that if I were to go over a scale, with out a trailer I am over weight.



So, basically, DMV allowed me to chose my registeration weight. and the transmission dictated my allowable tow capacity. How about this, Most Tractors are registered at 80,000 pounds, an overweight permit, and you can go as high as you want, providing you stay under the max allowed axle weights. Someone correct me if I am wrong, Does Kenworth or Mack say that their tractor is rated to tow X amount?



Does anyone know what the DOT says the max allowed axle weight is for a pickup truck?

 

[Road Dog]

The registered (or licensed) weight at the DMV is unrelated to the GVWR. It's the total weight you're allowed to haul including truck, trailer & payload. Certain trailers -- like RV trailers -- aren't normally included in the registered weight (or they have their own registered weight depending on your point of view).

Just to confuse things, on my insurance it's called "gross vehicle weight" when they really mean "licensed weight".

 

[BIGNASTY]

DR,



I had an 04. 5 quad cab 4x4 that I towed my first fifth wheel. It was a 29' Sprinter. The truck did very well. We upgraded to a 36' Cedar Creek. I had a spring shop add 2 full length rear leaf springs and I added a HD rear sway bar. The truck handled the weight as well as my later 06 dually but your immediate concern is your tires. Unfortunatly you can't hardly purchase single rear wheel tires to do all jobs safe. Unless you go to a 19. 5" set of wheels and tires. We had to make an emergency manuver to miss a dumpbutt dump truck driver at 50mph on I-24 north of Nashville. When we got stopped the first thing out of my wife's mouth was a dually was in our near future. Your model is a tuff truck but you will have to drive very conservatively.

I like that you had to make an emergency maneuver did someone not look far enough ahead. There are no emergency maneuvers just people not paying attention to what the H**L their doing

 

[MelvinPierce]

bromano676:

1. If you are over the registered weight, they can fine you for that overweight if you are heavier. At least here in ND, they are looking at doing that more and more, even for non-commercial vehicles. I register my 2500 for 25,000#, so that even with the Valkyrie and sidecar in the garage in the toy hauler, I am under the 25,000#.

The registered weight is usually the total, ie GCVW of everything. A few states may differ on non-commercial vehicles. As far as I know, ALL states are this way on commercial vehicles.

2. No, Pete, Mack, etc, do NOT have a tow weight, or GCVW ratings. They will go by the axle, which is dictated by how heavy an axle put in there, usually 34,000 to 38,000 pounds on a tandem drive axle set up.

3. Most states have a 20,000# single axle weight limit. For the axle. Now, you will not get near that. So, you go to the tire width. Most states have a 550# per inch of width restriction, some allow a little more. That will be your next restriction. If you want to carry 8,000# on the rear axle, you will need to have a total of 14. 5" of tire, so with two rear tires you would need each to be 7. 25" of tread on the ground.

If you had a dually, and had 4 8" tread width tires, the tires would allow you to go to 17,600#. Still not to the weight limit of 20,000#, but the tires would limit you. However, the vehicle axle rating would not be near that high. There is a question here as to how often, and in what jurisdictions, you would be held to that lower mfg. rating.

MP

 

[MelvinPierce]

I like that you had to make an emergency maneuver did someone not look far enough ahead. There are no emergency maneuvers just people not paying attention to what the H**L their doing

Pretty self important statement here: saying that ANY emergency manuever could be avoided.



So, I am passing a truck, and just before I get to the rear axle, a tire blows out, and the casing comes across towards my pickup.



That is my fault that I need to manuever to get out of the way?



GET REAL.



I do feel a lot of the times it could be avoided, just not ALL the time as you suggest.

 

[BIGNASTY]

I have a 04. 5 CCLB with single rear wheels ATX AT2 rated for 3195lbs Firestone airbags. I have been moving a boat load of stuff to Montana with my truck and a Big Tex 102x30 gooseneck tandem axle tandem wheel trailer. The trailer had 15k as much as I could get on the tandems. I have had breakfast with several Utah troopers and they seen what I drove in. I pulled into the scales in Montana at the 200/83 split to catch a few winks didnt want to get to inlaws in the middle of the nite. The Montana trooper came out to see if I was ok he said the coffee was on in the coop so I drove across the scale and went in for coffee. Even with 2k on the pin of the trailer NOT a thing was said except that those Dodge trucks and tuff as hell. I looked outside and both of them had Dodge. I think that they have bigger fish to fry than I . On a side note my truck is mostly stock no chip just a few filter add on's and trans pan rear cover and it has handled the weight several times on the same trip just fine I think the key is to drive like a human being BTJMO and all on a not good for anything 2500 :-laf

 

[BIGNASTY]

Pretty self important statement here: saying that ANY emergency manuever could be avoided.



So, I am passing a truck, and just before I get to the rear axle, a tire blows out, and the casing comes across towards my pickup.



That is my fault that I need to manuever to get out of the way?



GET REAL.



I do feel a lot of the times it could be avoided, just not ALL the time as you suggest.

So your saying that you are going to swerve to get away form the road gator. Sure it may do some damage to your pride and joy but swerving is the last thing I would do. I guess it comes from to many years of driving Tanker trucks in them if you swerve you flip the truck its very hard not to but it can be done. I was involved in some moron that stoped in the middle of the 710 frwy at 12. 35 am at Del Almo south bound as you wont know its very dark on that spot. Long story short I didnt swerve I wanted to go home that day and the fool that was in the Frwy. DIDNT Im sorry for him but because of his stupid move I have to live with that Kodak moment of him going under my truck for the rest of my life. So I guess your rite ALL is allot to ask for but MOST can be avoided if people would just pull their head out