2019 Tahoe Towing Guidance

[baare657]

My wife has expressed an interest in an RV travel trailer. I'm curious of the capability of our current equipment, as well as some information and experience you folks have had in your endeavors:
2019 Tahoe
5.3L V8
Axle ratio 3.08
Standard trailering package (not the max trailering package).

Please bear with me while I set this up:

Dealer's keep telling me "it is specified to tow up to 6400 lbs". I think they got the number with some math of the available specs:
GCVR : 12000
GVWR: 7300
Curb: 5602

GCVR - curb = ~6400 (rounded up)

I weighed my Tahoe, full tank with kids seats and other daily crap, no passengers:
actual curb : 5641

As an experiment, I picked a trailer with a dry weight of 4698: Grand Design Imagine XLS 21BHE

After weighing some travel items and doing some calculations, I think i am still within specs:
Vehicle Capacity : (GVWR - (Curb + tahoe payload + tongue)) > 0
After calculations, this equation comes to : 340.9lbs to spare (within spec)

Towing Capacity: (GCWR - (Curb + tahoe payload + trailer UVR + trailer payload)) > 0
After calculations, this equation comes to: 52.9lbs to spare ( i can move some things around to get this number closer to 300 lbs)

I've had difficulty finding anyone at the dealership who is willing to have a technical discussion.
We love the mountains, and would like to set up camp there.

I've tried to remain conservative, but the question remains:
Without the max trailering package (increasing capacity by 2K), assuming I remain within the specs, is this a safe, legal and practical endeavor?
Anyone out there with similar specs who tows a comparable camper?
Aside from a trailer brake controller, any other must-have additions?
What do have in your RV when you tow?

I've attached my spreadsheet, feel free to tell me i'm an idiot, but please tell me why as well. I'm well aware that i cut twice and say "its still too short!".
Thanks in advance. I've already learned alot reading through these posts.
-mb

 

[TJ&LadyDi]

I'm not sure how either you or the dealer arrived at your numbers. GCVWR is 12,000, GVWR of Tahoe is 7,300. GCVWR - GVWR = rated tow capacity and 80% of the computed "rated tow capacity" is considered maximum safe towing capacity.

"Curb" isn't a recognized rating as far as I know. If it relates to an empty vehicle, then you need to add the weight of fuel, passengers, cargo, etc. which is what GVWR tells you. Dealers frequently don't know (and/or don't want you to know) what the real tow ratings are.

So, GCVWR - GVWR x .80 gives you a generally recognized safe towing capacity.

(12,000 - 7,300) x .80 = 3,760

Unless I am misunderstanding something, I would say your proposed scenario doesn't work. Remember, safe towing capacity is more than how much you can pull. It also relates to how much you can safely stop, control, etc. Axle ratios are meaningless in that scenario.

TJ

 

[baare657]

I'm not sure how either you or the dealer arrived at your numbers. GCVWR is 12,000, GVWR of Tahoe is 7,300. GCVWR - GVWR = rated tow capacity and 80% of the computed "rated tow capacity" is considered maximum safe towing capacity.

"Curb" isn't a recognized rating as far as I know. If it relates to an empty vehicle, then you need to add the weight of fuel, passengers, cargo, etc. which is what GVWR tells you. Dealers frequently don't know (and/or don't want you to know) what the real tow ratings are.

So, GCVWR - GVWR x .80 gives you a generally recognized safe towing capacity.

(12,000 - 7,300) x .80 = 3,760

Unless I am misunderstanding something, I would say your proposed scenario doesn't work. Remember, safe towing capacity is more than how much you can pull. It also relates to how much you can safely stop, control, etc. Axle ratios are meaningless in that scenario.

TJ

Outstanding, that's exactly what I was looking for. Thanks TJ.
Is there an industry standard or a standards body that dictates the rated vs maximum safe towing capacity? or is this more tribal knowledge/common sense?
I arrived at these numbers after discussing with Chevy dealers, RV dealers, youtube and google. Example, "2019 Chevrolet Tailoring guide"

Very good point about what dealers don't want you to know. Its been impossible to get anyone who works in any capacity with Chevrolet to have a technical discussion with me.

This tells me we need to upgrade our vehicle to tow an RV that would be useful for my family. thanks again,
-Matt

 

[TJ&LadyDi]

Outstanding, that's exactly what I was looking for. Thanks TJ.
Is there an industry standard or a standards body that dictates the rated vs maximum safe towing capacity? or is this more tribal knowledge/common sense?
I arrived at these numbers after discussing with Chevy dealers, RV dealers, youtube and google. Example, "2019 Chevrolet Tailoring guide"

Very good point about what dealers don't want you to know. Its been impossible to get anyone who works in any capacity with Chevrolet to have a technical discussion with me.

This tells me we need to upgrade our vehicle to tow an RV that would be useful for my family. thanks again,
-Matt

Hi, Matt.

The 80% figure is a combination of common sense and good engineering practice. It is based on the thought that it is never good engineering practice to load any mechanical device at its maximum rated capacity as that leaves no room for error. Now, one can argue that the vehicle weigh ratings (GWR, GCVWR, etc.) have some "overhead" built into them but you have to establish some base level from which to do extrapolations. The 80% factor has become generally accepted among many RVers. That certainly doesn't mean that if you load something to 85% of rated capacity bad things will always happen.

The other issue with the Tahoe and other similar vehicles is that they have a relatively short wheelbase. This can exacerbate any handling issues. A longer wheelbase truck smooths things out.

Good luck with your search.

TJ

 

["EZ"]

I'm not sure how either you or the dealer arrived at your numbers. GCVWR is 12,000, GVWR of Tahoe is 7,300. GCVWR - GVWR = rated tow capacity and 80% of the computed "rated tow capacity" is considered maximum safe towing capacity.

"Curb" isn't a recognized rating as far as I know. If it relates to an empty vehicle, then you need to add the weight of fuel, passengers, cargo, etc. which is what GVWR tells you. Dealers frequently don't know (and/or don't want you to know) what the real tow ratings are.

So, GCVWR - GVWR x .80 gives you a generally recognized safe towing capacity.

(12,000 - 7,300) x .80 = 3,760

Unless I am misunderstanding something, I would say your proposed scenario doesn't work. Remember, safe towing capacity is more than how much you can pull. It also relates to how much you can safely stop, control, etc. Axle ratios are meaningless in that scenario.

TJ

One slight correction here. The rear axle ratio DOES play a very important part in determining the GCWR which would effect your towing capacity. This is not important for a Tahoe because they may only offer one ratio. But in a 2500/3500 pickup there offer at least 3 ratios. Here is how it effects the Ram 2500/3500 GCWR with the Cummins engine and the Aisen auto transmission................
3.42 25,300 lbs
3.42 29,300 lbs
3.73 33,800 lbs
4.10 39,100 lbs

This comes from my Ram pocket guide for Towing and Payload. Not sure why the 3.42 has 2 different ratings. I'd have to do some more digging. I'm assuming the 3.42 is available with the smaller Chrysler built transmission or it's a SRW rather than a DRW axle.

 

[TJ&LadyDi]

One slight correction here. The rear axle ratio DOES play a very important part in determining the GCWR which would effect your towing capacity. This is not important for a Tahoe because they may only offer one ratio. But in a 2500/3500 pickup there offer at least 3 ratios. Here is how it effects the Ram 2500/3500 GCWR with the Cummins engine and the Aisen auto transmission................
3.42 25,300 lbs
3.42 29,300 lbs
3.73 33,800 lbs
4.10 39,100 lbs

This comes from my Ram pocket guide for Towing and Payload. Not sure why the 3.42 has 2 different ratings. I'd have to do some more digging. I'm assuming the 3.42 is available with the smaller Chrysler built transmission or it's a SRW rather than a DRW axle.

You are correct that the axle ratio plays a role in determining GCVWR, but only from the standpoint of how much you can pull safely. It doesn't play a role in the ability to stop (OK...maybe a very tiny part theoretically) or in handling. My point was that choosing a different axle ratio doesn't really alter what the vehicle can safely tow, all things considered.

TJ

 

[Kevin D Pem]

The 80% figure is a combination of common sense and good engineering practice. It is based on the thought that it is never good engineering practice to load any mechanical device at its maximum rated capacity as that leaves no room for error. Now, one can argue that the vehicle weigh ratings (GWR, GCVWR, etc.) have some "overhead" built into them but you have to establish some base level from which to do extrapolations. The 80% factor has become generally accepted among many RVers. That certainly doesn't mean that if you load something to 85% of rated capacity bad things will always happen.

Max rated capacity is in fact the max the vehicle can deal with, no fudge room. All things related to this include cooling system, brake heat build up, transmission heat and anything involved in the vehicle as a system. Braking of the load is only vehicle and 2000 lbs trailer, the rest is figured to be stopped by trailer brakes. Question this? Try stopping the load with trailer brakes disconnected.

The size not ratio of the rear end is what is important for tow capacity as the gears will break if overloaded, the axle may bend and produce miss alignment of gears and bearings. But this rating, again is max load rating, don't go fast through a bump.

durability and the amount of time one can haul the max is typically limited by something called duty cycle. Most of the time fully loaded machinery of any form has a duty cycle of 50%. Although this duty cycle can work for short distances and may shorten equipment life, it will not work for long distances. The number of grade will change the duty cycle, as the rated capacity is on level ground. To obtain a useful duty cycle we call for 80% towing capacity. This too is on level ground and considers fuel stops on the 20gal gas stop (or whatever standard tank is for your vehicle) as a cool down period. In other words at 80% weight capacity we are not at 100% duty cycle but If we consider the stops along the way it works. When you see a Truck/trailer combo on a hill with the hood up you are seeing what happens when we are overloaded or pushing duty cycle because of a hill/whatever.

In summary even if we load at 80% gcvw we can be missing the mark on the duty cycle, and have problems we thought we shouldn't have based on manufacturer numbers. At some point the user has to take responsibility to assure reliable operation of the machinery. This responsibility included understanding the numbers based on duty cycle, and watch the system indicators(temp gauges) and keep the systems at the proper limits by slowing on hills if required, lower duty cycle in high temperature areas, or using lower gears in heavy traffic when needed. I call this babying the rig.

 

["EZ"]

My point was that choosing a different axle ratio doesn't really alter what the vehicle can safely tow, all things considered.

TJ

With all due respect, you need to keep this advice to yourself. It is incorrect. I just showed you the Engineering data where the axel ratio can change the towing capacity from 25,300 lbs. to 39,100 lbs. IN THE SAME TRUCK! If a person that doesn't know any better goes into a dealership and asks the salesman "what about the axle ratio" and the salesman says "the axel ratio doesn't really alter what the vehicle can safely tow" (your words) he could be sending the guy down the road in a new truck that is dangerously incapable of towing the fifth wheel he is planning to buy because he was told the axel ratio doesn't really matter. There is enough misinformation in the market place already without telling people the axle ratio doesn't really alter what the vehicle can safely tow. It matters a great deal. I've been spec'ing commercial trucks out for various applications for 30 years. I actually sold chassis into the TOWING and Recovery industry for 15 of those years. I know a thing or two about truck spec's and towing. Sorry for the rant................now back to your regularly scheduled broadcast.

 

[Kevin D Pem]

With all due respect, you need to keep this advice to yourself. It is incorrect. I just showed you the Engineering data where the axel ratio can change the towing capacity from 25,300 lbs. to 39,100 lbs. IN THE SAME TRUCK! If a person that doesn't know any better goes into a dealership and asks the salesman "what about the axle ratio" and the salesman says "the axel ratio doesn't really alter what the vehicle can safely tow"

Hey @"EZ" I understand from where you are coming. Other than very large trucks most of the time under powered for the size and capacity I would think. Gear ratio in the rear end pumpkin has little to do with the weak link of the system. It does have a lot to do with tow power however. When you spec a truck for a load I would think the table takes into account the life of universal joints, twisted drive shafts and pinions asked to do more than they should. The compromise of low gears in today's world are transmissions with overdrive, last 2.5 ton truck I drove had a two speed rear end, now days the over drive is the answer. Good off the line power because of the almost 4:1 ratio and low RPM because of the over drive gears, that must be locked out or trans failure is soon to come.

No matter what the gear ratio in the rear end, HP determines the high end speed, because the HP is the figure that determines the speed that the work can be done. The gear ratio and torque determine that it can be done HP is moot at the first gear reduction, it is then torque.

You sell a lot of trucks for commercial customers. I will let you know that when I bought my truck at Downtown Dodge in Vernal UT. I asked for the tow capacity of the truck. The salesman (sales manager in my case) pulled up the VIN and the answer was right there on the spec page for my future truck as built. So my answer was from an engineers data sheet like you showed us in your post. For the rest of you it is good to ask for this info before you buy. It is not that the information is not there. It is not that they want to hide it from you. Quite frankly it is because your salesman is to lazy to do his job, if he won't look it up for you. Find another dealer if they won't work with you.

 

[TJ&LadyDi]

With all due respect, you need to keep this advice to yourself. It is incorrect.

Looks like we need to agree to disagree and move on. ?

TJ