Workhorse Gross Combined Vehicle Weight Ratings

[Full.Monte]

Hi Guys,

My P32 has a GCVWR of 18,000 lbs. I know a couple Workhorse guys who have ratings much higher than mine with longer wheel bases and the same 8.1 engine. Can anyone explain why my GCVWR is lower than theirs?

If I tow a toad 4-down, I'm not adding weight to the motorhome, just to the towed weight.

[Alan_Hepburn]

There are differences between your P32 chassis and the Workhorse chassis - differences in the frame itself, the suspension, the drive train, running gear, etc.



Towing 4-down doesn't affect the motorhome's suspension (too much) but it definitely affects the drive train and running gear.

[edgray]

Originally Posted by Full.Monte

Hi Guys,

My P32 has a GCVWR of 18,000 lbs. I know a couple Workhorse guys who have ratings much higher than mine with longer wheel bases and the same 8.1 engine. Can anyone explain why my GCVWR is lower than theirs?

If I tow a toad 4-down, I'm not adding weight to the motorhome, just to the towed weight.

FM: First let's get your facts straight. According to your signature, you have a P32 with 18,000 GVWR. Assuming that is correct, your GCWR is 21,000 pounds.

As you most likely know, the GCWR is the max weight you should be carrying on the coach axles COMBINED with the weight of whatever is being towed (regardless of how many axles that has). However, even if you are not towing anything, the coach GVWR still limits you to 18,000 total pounds on its two axles.

As to your questions, both the GVWR and the GCWR are determined by the engineers and are the ratings of components such as the engine, tranny, axles, suspension, BRAKES, and tires. Each of those components has its own rating, and generally speaking, it is the weakest link that determines the final GV and GC rating. For example, I believe your P32 brakes are less powerful (capable) than those found on the W-22 series chassis that provides a 26,000 pound GCWR. Likewise, the W-22 brakes are not as capable as those found on the W-24 series that provides a 30,000 pound GCWR. The W-24 series has larger rotors, pads, and 4 piston calipers compared to the W-22 with 2 piston calipers. I chose the power of the brakes to demonstrate my point because IMO, that is likely to be the biggest SINGLE factor in determining the ratings, but obviously the ability of the tranny to pull the load would be another significant factor.


You are right about a toad not adding weight to the GVWR of the coach, but the toad IS adding weight that must be pulled by the tranny and stopped by the brakes. IMO, that is why the additional pounds of combined weight for the P32 is only 3,000, compared to 4,000 for the W-22 series, and 6,000 for the W-24 series. Hope all this helps...Ed

[Alan_Hepburn]

Originally Posted by edgray

You are right about a toad not adding weight to the GVWR of the coach, but the toad IS adding weight that must be pulled by the tranny and stopped by the brakes. IMO, that is why the additional pounds of combined weight for the P32 is only 3,000, compared to 4,000 for the W-22 series, and 6,000 for the W-24 series. Hope all this helps...Ed

One little comment: I'm pretty sure that the engineers specify the brakes so that they can handle the GVWR of the chassis, and NOT the GCWR - that's why they specify that anything being towed should have its own braking system.

[Rocky Larson]

Let me take an educated guess.. You have 19.5 inch tires? They have 22.5?

[Mr_D]

Originally Posted by Alan_Hepburn

One little comment: I'm pretty sure that the engineers specify the brakes so that they can handle the GVWR of the chassis, and NOT the GCWR - that's why they specify that anything being towed should have its own braking system.

Absolutely TRUE!

[Full.Monte]

Originally Posted by Rocky Larson

Let me take an educated guess.. You have 19.5 inch tires? They have 22.5?

Yes, I do have 19.5 inch tires.

[Full.Monte]

Originally Posted by Alan_Hepburn

One little comment: I'm pretty sure that the engineers specify the brakes so that they can handle the GVWR of the chassis, and NOT the GCWR - that's why they specify that anything being towed should have its own braking system.

Yes, the toad has it's own braking system, which is superior to the stopping power of the P32. If I turn up the braking on the toad, I can feel it slow down the motor home when stopping.

[Full.Monte]

Originally Posted by edgray

FM: First let's get your facts straight. According to your signature, you have a P32 with 18,000 GVWR. Assuming that is correct, your GCWR is 21,000 pounds.

As you most likely know, the GCWR is the max weight you should be carrying on the coach axles COMBINED with the weight of whatever is being towed (regardless of how many axles that has). However, even if you are not towing anything, the coach GVWR still limits you to 18,000 total pounds on its two axles.

As to your questions, both the GVWR and the GCWR are determined by the engineers and are the ratings of components such as the engine, tranny, axles, suspension, BRAKES, and tires. Each of those components has its own rating, and generally speaking, it is the weakest link that determines the final GV and GC rating. For example, I believe your P32 brakes are less powerful (capable) than those found on the W-22 series chassis that provides a 26,000 pound GCWR. Likewise, the W-22 brakes are not as capable as those found on the W-24 series that provides a 30,000 pound GCWR. The W-24 series has larger rotors, pads, and 4 piston calipers compared to the W-22 with 2 piston calipers. I chose the power of the brakes to demonstrate my point because IMO, that is likely to be the biggest SINGLE factor in determining the ratings, but obviously the ability of the tranny to pull the load would be another significant factor.


You are right about a toad not adding weight to the GVWR of the coach, but the toad IS adding weight that must be pulled by the tranny and stopped by the brakes. IMO, that is why the additional pounds of combined weight for the P32 is only 3,000, compared to 4,000 for the W-22 series, and 6,000 for the W-24 series. Hope all this helps...Ed

Thanks, Ed...that makes sense, except that if the towed vehicle has it's own braking system, it wouldn't be dependent on the braking of the motorhome for stopping. But the tranny and the rest of the drive train and the chassis would feel it, I agree.

[edgray]

Originally Posted by Alan_Hepburn

One little comment: I'm pretty sure that the engineers specify the brakes so that they can handle the GVWR of the chassis, and NOT the GCWR - that's why they specify that anything being towed should have its own braking system.

Then why bother to provide a GCWR at all?

[edgray]

Originally Posted by Rocky Larson

Let me take an educated guess.. You have 19.5 inch tires? They have 22.5?

There are quite a few W-22 series chassis with either 20,700 (W-20) or 22,000 (W-22) GVWR that have 19.5" tires and wheels, so the P32's 18,000 GVWR isn't due to the use of 19.5" tires

[dieselclacker]

Originally Posted by edgray

There are quite a few W-22 series chassis with either 20,700 (W-20) or 22,000 (W-22) GVWR that have 19.5" tires and wheels, so the P32's 18,000 GVWR isn't due to the use of 19.5" tires

Ya beat me to it ed.������ I have one of those 20,700 pounders.

[hawkeye1995]

I have a Workhorse P32. I will tell you you the brakes scare me to death!, but they do work. They have such a long travel, but when I had to stop in a hurry, they got the job done! I'm sure the toad brakes helped a lot too.



I'm sure the transmission has a lot to due with tow weight. I have the standard GM tranny, which limits my gross weight to 21000 lbs. I'm sure the W-20, W-22, and W-24 all have different frame builds, suspensions and use the Allison Transmission. Thus it allow for more gross weight, and tow weight. Tires do play a factor in weight allowed, but nut the overall deciding factor.
I have no doubt that I could not tow more than 3000 lbs. It is just that the tranny would not hold up. The engine has all the power in the world! My little HHR weights around 3000 and I have no problems at all. I would bet I could tow my Chevy 1500 truck, but again, the tranny would be the weak point.
Us P32 owners have to just suck it up, and not carry as much in the MH. I don't load a lot when we travel. Carry some tools, spare parts, fishing equipment food and a change of clothes. I only carry about a half of tank of water, at most.

It would be nice if I could carry more weight, but it is what it is. I still enjoy the journey.

[Alan_Hepburn]

Originally Posted by edgray

Then why bother to provide a GCWR at all?

Bcause there are other considerations besides braking performance, such as transmission performance that are included in the GCWR.