General HP vs toad (check my numbers)

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Ok folks, this is loyal hubby, so if I?m woofing up a dry creek, yell at me, not my cute wife?..

We bought a used 31.5 Gulfstream DP, 210 Cummins, four speed Allison Auto.  Only after extensive shakedown cruises I am considering towing my wife?s Jeep Grand Cherokee (4 down).  The data and information I have gathered to date is as follows:

Coach scale weight dry with ?  tank of fuel: 12,250
GAWF       7,000
GAWR             12,000
GVW     19,000
GCWR             22,500
Hitch rate       5,000
Jeep Weight (to be scaled)       4,600

Estimated water & waste (full)       1,750
Estimated additional fuel     400

Two passengers (yea yea yea) 300
Three dogs         200

Here?s my math:

Total Coach without cargo with cushion 15,000

With dogs and people without cargo           15,500

Coach, People, Dogs and Toad     20,000

So I see a cargo and supply ?allowance? MAX of 2,500

The current thinking is a Roadmaster 6,000 pound rated hitch with SMI brake system (Silent Partner).  This is well within tolerance it appears, as long as I always observe the cargo issue, and subject to visits to the scales.

I think I figured this out with a margin of safety, but in your opinions, am I asking for abysmal performance on the road?  It is within the ?1 HP per 1,000? guideline I saw on a forum, but being a bit skittish, very safety conscious and conservative,  what do ya?ll think?

Thanks a million for the input!

Sorry, I tried to line up the numbers ( nice and pretty) but it wouldn't hold the change - just don't get dizzy reading them :)


Jan 13, 2005

A couple of clarifications on your numbers:

The GVW of 19,000 lbs you quote must be the GVWR. (GVW = gross vehicle weight and GVWR =gross vehicle weight rating).

Have you confirmed the manufacturer's tow rating of this coach? I'm not talking about the "5,000 lbs" rating of the hitch - it could have a 10,000 lbs hitch welded to the chassis, but that doesn't mean it's safe to tow 10,000 lbs. Normally, I'd calculate it this way:

Tow rating = (GCWR - GVWR) = (22,500 - 19,000) = 3,500lbs.

Your numbers suggest that you're trading weight between the coach and the towed vehicle to stay within the GCWR. This may be OK, but I'd still want to confirm that you can safely tow that Jeep before hooking it up.

Otherwise, the numbers look OK.

I can't predict what the performance will be, but maybe someone with a similar coach/engine/transmission/toad combination will jump in.

Want to thank everybody for their input.  Raised a few more questions that I'll ask Spartan (i.e. can I borrow weight allowance from coach for toad?).

But, took the Grand Cherokee to be weighed today and it came in at an actual weight of 4950, that made the decision to NOT tow it very obvious.  We're checking around for something that will meet our needs and tow weight allowance.

However, I did learn a couple things:
First and foremost - what a helpful group is on this forum
Don't believe dingy guides, manufacturer's websites, etc for weight - the only way to know for sure is to actually get the vehicle on a scale.


Jan 13, 2005

You're absolutely right about the need to get the vehicles on the scale.

I'd be interested in the response you get from Spartan to the tow rating question.
Gulfstream 31.5 210 HP DP towing a Jeep Grand Cherokee Ltd.

Here's the E-Mail (edited to eliminate extraneous information) I sent Spartan regarding tow capacity on the aforementioned toad:

Being new to chassis weight ratings and other issues regarding towing, I have a general question. I hope someone at Spartan can answer this:

The GCWR is 22,500
The GVW is 19,000

Difference 3,500

Is the 3,500 an absolute limit on a towed vehicle weight, or if the coach actually weighs only, say 18,000 loaded, could we go with a towed vehicle rating of 4,5000 (the hitch is rated for 5,000). To say it another way, can "excess" limit on the coach be used for the towed vehicle (e.g. "borrowed")?

Hopefully this will be my last silly question, but I do appreciate Spartan's support and help!

On another matter, I ordered a couple of parts from Spartan - the Parts Department was very helpful and professional, and filled the order promptly.

Response from Spartan Chassis:

If the coach weighs only 18,000 fully loaded, you can "borrow" the left over weight from the coach to utilize for the tow, as long as the tow vehicle does not exceed the hitch rating. So, in your senario, you could tow the 4,500 pound vehicle.


Retail Customer Service Representative
Spartan Chassis, Inc.
1165 Reynolds Rd
Charlotte, MI 48813
(800) 543-4277
[email protected]

Of Further Note:

We'll be weighning the coach early next week and will post the results....

Thanks for all of the help, folks! Truly helpful!  :) :) :)


Jan 13, 2005

Thanks for the follow-up, it's much appreciated and I learned something new today.
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