GM Towing increases

[skrizan]

My 2008 GMC Sierra Extended Cab Standard Box 4WD 5.3 Flex fuel lists my max trailer towing capacity as 7500lb and GVWR as 13,000.

The same model in 2011 lists max trailer weight as 9600!

How much of this increase has anything to do with changes to the vehicle, and how much of it is just increased due to more thorough testing and the fact that Ford has been boasting 10,000 for their 1/2 ton?

Also, I have the 3.73 gear ratio; if I had the 4.10 I could tow 8,500.

The 2011 that tows 9,600 has 3.42 ratio, using the logic that higher is better, shouldn't mine tow even more than the 3.42?

One other thing, I have the Heavy Duty trailering package. There is no reference to this in the manual, does this add any towing, or if you don't have it you should subtract?
I have the 4 speed transmission, not the 6 speed, but the towing capacity doesn't reference transmission type, so I don't think it matters.

I made the mistake of thinking I had 8,500 capacity and purchase a 7000lb camper, when loaded I will be pushing the limit if not over by a few hundred. I don't want the mileage decrease or cost increase of a 2500, and I don't want to buy a new 1500 and find out there really isn't much difference.


Any thoughts/comments are appreciated, and facts even better!

[shorod]

I'll start off this post stating that I am speculating here and have no real background to support these thoughts. But giving others some theories to shoot holes in to sometimes increases the opportunity for useful information....

If you have access to the owner's manual for both model years you might check the cooling system capacity specification. Part of the increased towing capacity could be due to the a larger capacity cooling system. Since trailers over 3500 lbs (or somewhere around there) are now required to have trailer brakes, I'm not sure if the towing capacity increase could also be due to upgraded brakes on the 2011. Are the HP and torque specs for the 2011's drivetrain the same as for you 2008? There could be software/firmware improvements that enable the higher towing capacity as well. If so, you may be able to recover some towing capacity with a programmer but I'm not sure any programmer would advertise increased towing capacity or that you'd want to go that route since you probably still have some factory warranty remaining.

And there is always a good chance that their reliability engineers and bean counters conferenced to determine what the least expensive way is to compete (on paper at least) with Ford, Dodge, and Toyota. In the process they MAY have determined a for a slight increase in warranty claim risk they could up the specs by a ton.

-Rod

[curtis73]

Trailer towing capacity and GVW are both highly political numbers. They are a one part bean-counters covering their butts for warranty issues, one part actual truth, and one part competition.

A good example - my 98 F150 extended cab short bed in its configuration is rated to tow a measly 6500 lbs. If it had the single cab long bed, (same wheelbase) it would be 8000 lbs. Why? Probably because they assumed that people buying a long bed single cab would need more "utility" and those buying the ext cab wanted more daily driving. They could lower the tow capacity, save some $ on warranty repairs, and not really affect sales that much.

[jdmccright]

There are lots of factors that determine the towing capacity:

1) engine
2) transmission
3) axle ratio
4) frame construction
5) 2wd/4wd
6) cooling capacity
7) cab/bed configuration (regular, extended, crew...long or short box)

You would really have to compare the two truck's setups to see what is different.

The other possibility is that they had gathered enough real-time information to warrant an increased towing capacity...repair data, test data, etc. They may have kept it conservative in lieu of having supporting data.

[MagicRat]

In addition to the above, the trailer itself has a lot to do with it.

Does your camper have dual axles? Good brakes on each wheel? Fifth-wheel or weight-distribution hitch?

These factors make a difference, because a dual axle set up and fifth wheel are inherently more stable, and the advantage to 4 wheel brakes is obvious.

Imo such trailer design features make a bigger difference than the weight itself.

Frankly, the only way I would tow 7000 lbs without good brakes is with a tandem axle dump truck.

[jdmccright]

Your GVWR is based on your truck's factory installed equipment including trailer and heavy duty cooling options. They dont say what the limiting factor is even though we wish they would. The number is what it is. And sorry MagicRat, but i have to somewhat disagree...no matter how tricked out the trailer is, the truck still ultimately has to haul and control it. Dual axles doesn't make a 10k-lb trailer easier to pull up a steep grade (though yes the extra pair of brakes can help stop it, the extra axle is primarily to distribute the weight among more tires).

Back to the original post:
I'm going to guess that the new truck has a better transmission, larger brakes, and beefier suspension to achieve the higher numbers. Yes you'd think that a truck with a 3.73 axle would tow more than one with a 3.42. But this is really an apple-to-orange comparison. The new model has been improved in other areas to make the taller gear unnecessary for the average hauler, and likely gives better fuel economy to boot.

Now officially, you shouldn't tow above the GVWR and safety should be forefront. However, you can eke a few extra hundred pounds capacity by swapping for 2500 components...shocks, springs, brakes, radiator, etc. Just remember that the truck is only as strong as it's weakest link, so upgrade all around and give yourself confidence the truck can do the job safely. If you're unsure, stop by any trailer retailer and ask their opinion on all that should be done...they've answered that question a thousand times already.

Good luck!

[HeavyJ]

I wanna add my 2 cents to this subject. BRAKES! Your vehicle was equipped from the factory with what most consider high quality brake components, pads/shoes, rotors, etc. What brake work has been done on your vehicle? Has premium parts been used? I see too many times people cheap out on brake parts, then complain they wear out too fast, don't stop as quick, and if they do tow, it's "what the heck happened to my brakes, I couldn't get stopped as quick". Lucky they didn't plow into something.

[MagicRat]

Originally Posted by jdmccright

And sorry MagicRat, but i have to somewhat disagree...no matter how tricked out the trailer is, the truck still ultimately has to haul and control it. Dual axles doesn't make a 10k-lb trailer easier to pull up a steep grade (though yes the extra pair of brakes can help stop it, the extra axle is primarily to distribute the weight among more tires).

While I agree with your comments, let me expand on my points a bit.

The recommended trailer towing weight is imo very arbitrary, and its not reasonable to put too much faith in that figure.

For example, is a 7000 lb trailer "safe", and a 7001 lb trailer dangerous? Of course not,

Imo this poster is fretting about details without looking at the big picture. In the real world, some trailers are safer to tow than others. So, going ONLY by the trailer weight is unreasonably narrow attitude.
Really, that camper could be 5000 lbs, but be unsafe to tow by a 1500 series pick up truck, depending on equipment, layout and weight distribution.

Engine power and coolant capacity are overrated in importance. Manufacturers use high power ratings to sell trucks, but in reality, any modern full size pick up has ample power to get a 7000 lb trailer moving down the road in a reasonable fashion. So long as you can keep up with the semi-trucks, you are going fast enough. Extra power is nice but not essential. Effective trailer towing then becomes an issue of trailer control and braking.

I must disagree about your comments on dual axles. Dual axles greatly reduce "polar inertia", or the tendency for the trailer to sway, and shift the truck side to side. Heavy, single-axle trailers need a much heavier tow vehicle to control them. Dual axles greatly reduce this tendency, and make a trailer much easier to control, especially for long camper trailers.

Imo a fifth wheel hitch is the best layout for towing with a pick up truck. They allow for far better trailer control than an ordinary Class III or IV hitch. If the trailer was not so designed, a weight distribution hitch is a great alternative.

Other suggestions? Learn how to use trailer brakes correctly. Applying trailer brakes alone, without applying the truck brakes is a valuable aid in retaining trailer control in some situations.

So, if his trailer is substandard, his money may be better spent on getting his trailer and hitch safe, especially brakes, than worrying about details like the truck radiator size. Doing so is not "tricking out" a trailer, but simply making it meet a basic, safe standard.

As you suggest, though, the entire rig, especially the trailer needs to go to a pro for at least an inspection of its fitness and compatibility.

[skrizan]

The trailer is a brand new dual axle 31'. I have a quality brake controller and Reese weight distibuting hitch and sway bar. My old trailer was 12 foot shorter and around 5000lb fully loaded. I towed the new trailer home yesterday. I didn't notice much difference as far as acceleration or braking, seems to be fine.
We had some pretty decent winds here in MI yesterday and I could feel more sway then I am used to, but nothing that seemed dangerous. The roads are horrible around here any more and I could definitely feel more bounce on the rough roads with the extra tongue weight. Smooth highways were fine except for the sway with the wind and semi trucks. My quandary is this - 1. I do not want to buy a 2500 and the low mpg that comes with it to haul a camper around MI 4 or 5 times a year. 2. I don't want to trade my 1500 in for another one that is rated for more towing and find out it really isn't much different at all.

[MagicRat]

Towing a bulky 7000 lb trailer will be a bit tricky regardless of the tow vehicle.

In my experience, a a slightly heavier duty pick up is not going to reduce the sway feel now, you would have to move up to a one-ton dualie to get that.

It may be reasonable to have someone upgrade the shocks and rear springs (perhaps add an extra leaf). But otherwise, imo nothing less than a 1 ton dualie will improve things.
If it feels safe to tow, live with it for a bit, before making a decision.

[jdmccright]

Thanks for clarifying MagicRat, I think that helps explain your first post alot...point well taken.

[curtis73]

If we're talking about a travel trailer, its a whole new ballgame. You (of course) still shouldn't exceed the max towing weight, but keep in mind you're towing a 31' billboard. That's massively different from towing a 30' flatbed with a couple cars on it.

I have a 65 1-ton pickup that I wouldn't tow a travel trailer with, but I have a 98 F150 that does quite well with one. Suspension design, steering geometry, tire sidewall stiffness, condition of suspension components, etc all play HUGE roles in how the truck will handle the weight and sway. The 65 is loose and uses old-school suspension design. The 98 is tight and ready to control a lot more side forces. In fact, my father and I were just comparing things like that this week... he had an 88 3/4 ton that doesn't tow my travel trailer as well as my 98 1/2 ton.

Then you factor in that the different brands of truck focus on different things and it becomes a widely political thing. Ford tends to get their weight capacity by using softer suspensions and stiffer frames. Dodge tends to get theirs with generally heavier components. Then all of a sudden a Chevy engineer sees that Toyota is advertising higher tow capacities on a new commercial so they modify the shift points of the transmission, add a bigger tranny cooler, and now they can claim the same numbers for the GM trucks.

Using the factory tow ratings to determine how well a truck will tow a trailer is just plain pointless. Yes, you should stay under the factory tow rating, but for a travel trailer, more is better. I'll tow a 12,000 lb flatbed with two cars on it with my F150 for short distances and it does great, but 26' travel trailer at 7500 lbs GVW is about all I'll do or things start getting squirrely in the breeze. I could make it more capable with stiffer E-range tires, but with a long travel trailer (regardless of trailer's GVW) you need a long truck. Period. Wheelbase will cover a lot of sins.

Let's face it, 7500 lbs can be towed by many 1/2 ton trucks, but in many ways I would rather have a long bed ext cab 1/2 ton than a single cab 1-ton to pull 7500 lbs if its a travel trailer.

[jdmccright]

I'll agree with you there Curtis. The tow ratings simply mean it is capable of doing it, not necessarily HOW WELL it can do so. More truck is definitely better for stability. If only I could push a button on the dash and make my 6-1/2' box extend to 8' and grow a set of duallys...dare to dream.

[curtis73]

Originally Posted by jdmccright

If only I could push a button on the dash and make my 6-1/2' box extend to 8' and grow a set of duallys...dare to dream.

I think we all wish we had a button that could "extend" something and help us grow a set.