Interpreting Weight Rating (GCWR)
Ken Creary
and GCWR and how to figure the max weight trailer for a specific
vehicle. What I'd like to understand better is the meaning of the
number. If I'm driving a vehicle loaded at the GCWR, does that mean the
engine can comfortably pull that load up hills or does it mean I should
jettison cargo and passengers to make it up the grade?
Thanks!
Ken
Ken Creary
Combination Weight Rating (GCWR.) However, GCWR definitely has a direct
relationship to Axle Ratio (taller gears will pull a greater load.)
lrm wrote:
> GCWR has nothing to do with how your engine will handle the load. It
> relates to the capacity of your axles. If you exceed the GCWR either per a
> specific axle or overall, you are in danger of breaking an axle (or other
> wheel componetry i.e. suspension members, over taxing break system etc.).
> Needless-to-say, it could be both expensive and very dangerous to life and
> limb!
lrm
Robert Carr
Just to be sure that we are understanding the two terms correctly.
GVWR(Gross Vehicle Weight Rating) is the maximum allowable weight for
the vehicle in question.This number is established by the
manufacturer. Example: a pickup truck loaded with cargo.
GCWR(Gross Combined Weight Rating) is the maximum allowable weight for
the two vehicles combined. This number is established by the
manufacturer. Example: a pickup truck loaded with cargo pulling a
trailer loaded with cargo.
Now to your question. My understanding is that the GCWR value
specified by the manufacturer, for a given vehicle(pickup truck) is
established by testing that vehicle against a set of "Performance
Criteria", that is set by the manufacturer. That "Performance
Criteria" is not a standard set, but created individually by each
manufacturer(Ford, GM, Dodge). This criteria, I would expect, is based
on what might be termed as reasonable or acceptable performance for
the various conditions to which this vehicle, combined with a trailer,
will be subjected. To my knowledge, this "Performance Criteria" is not
available to the general public. I don't know if it could be obtained
upon request. I kind of doubt it.
Now with that as background, let's address the ability to climb hills.
I would say that what may acceptable to you may not be acceptable to
someone else. What was acceptable to the manufacturer may not be
acceptable to you. I think you kind of get the picture. Generally
speaking, many people that participate in this newsgroup, recommend
not loading up to the allowable GCWR. More specifically, try to shoot
for approximately 75% of the maximum allowable trailer weight(GCWR -
tow vehicle weight). Check with the manufacture in case they provide
for other restrictions on calculating the maximum trailer weight. The
logic behind suggesting a lower trailer weight is it provides for more
comfortable towing, power reserve for steeper grades, travel at higher
elevations and the travel in head winds, potentially safer towing,
increased reliability, etc.
Hope this helps
Bob
On Sat, 17 Jun 2000 22:00:42 -0400, Ken Creary <kcr...@banet.net>
Ken Creary
boat/trailer weighs. Now I'm trying to determine which tow vehicle to buy.
The 75% of max trailer weight allowed seems to be a good rule of thumb to
use. I figured someone in this news group would have some good advice!
Thanks again!
lrm
Ken Creary wrote:
> I think you've just described Gross Axle Weight Rating (GAWR) not Gross
> Combination Weight Rating (GCWR.) However, GCWR definitely has a direct
> relationship to Axle Ratio (taller gears will pull a greater load.)
>
> lrm wrote:
>
> > GCWR has nothing to do with how your engine will handle the load. It
> > relates to the capacity of your axles. If you exceed the GCWR either per a
> > specific axle or overall, you are in danger of breaking an axle (or other
> > wheel componetry i.e. suspension members, over taxing break system etc.).
> > Needless-to-say, it could be both expensive and very dangerous to life and
> > limb!
> >
Greg Surratt
the Dodge Ram sales brochure says (in the very fine print at the
bottom of the tow ratings table) something to the effect that these
numbers are for "acceptable performance". The actual definition of
acceptable performance is left to the purchaser.
I recently picked up a trailer that was rated at the manufacturer as
"8968 lbs dry weight." I found that my Ram will pull it acceptably
(to me) at 55 mph (2250 rpm) in drive with the capablity to accelerate
well into the 80s in overdrive if I need it to. This was a trip from
Benson Arizona to Norfolk, Virginia. The truck downshifted a total of
twice at 45 mph (1500 rpm) and dropped to 40 mph on one hill coming
out of Las Cruces, New Mexico. That is "acceptable performance" to
me.
I also found that, while I have been upset with Dodge for telling me
that an engine brake is not acceptable with the automatic
transmission, I am now over that "snit". Even with this big trailer,
I can stay in drive and the torque converter will unlock and give me
sufficient braking power that I did not have to use the service brakes
on any of the hills on this trip. While safety is a consideration, I
feel that I have enough braking power without spending the $$$$ for an
exhaust brake that will be of questionable use or do damage to the
transmission.
When I got near the house, I pulled across a scale. The trailer is
actually closer to 11,000 lbs. with a GCWR of 17,780 lbs.
Greg
98 RAM, 24V Cummins, Auto, 3.54 rears and all the other options.
89 Nu-Wa Hitchhiker Champagne Edition, 35 ft Fifth Wheel, single slide
On Sun, 18 Jun 2000 02:48:50 GMT, Robert Carr <rac...@home.com>
wrote:
Tom Calhoun
Robert Carr <rac...@home.com> wrote in message
news:eacokson88kte2uit...@4ax.com...
> Ken
>
> Just to be sure that we are understanding the two terms correctly.
>
> GVWR(Gross Vehicle Weight Rating) is the maximum allowable weight for
> the vehicle in question.This number is established by the
> manufacturer. Example: a pickup truck loaded with cargo.
>
> GCWR(Gross Combined Weight Rating) is the maximum allowable weight for
> the two vehicles combined. This number is established by the
> manufacturer. Example: a pickup truck loaded with cargo pulling a
> trailer loaded with cargo.
>
My '98 Chevy truck manual, door plate, glove box sticker give the GVWR and
both GAWRs, but not the GCWR.
Where can I find out the GCWR?
Thanks, Tom
David Osborn
>My '98 Chevy truck manual, door plate, glove box sticker give the GVWR and
>both GAWRs, but not the GCWR.
>
>Where can I find out the GCWR?
>
Pik up a brochure at your local dealer. The proper one should list GCWR
as a function of transmission, engine, and rear-axle ratio.
- - - - -
David, N8DO; FMCA 147762
djosborn at aol dot com
Robert Carr
Tom
My 97 GMC truck stickers identified the same information as yours. I
have always obtained the GCWR from the GMC Trailering Guide for the
model year in question. I would think that Chevy does the same. I
don't know this to be true, but possibly your VIN(Vehicle
Identification Number) could be taken to a dealer for information
retrieval. The information associated with that VIN might include the
GCWR. I would still think that a better possibility is the trailering
guide. Maybe dealers keep back copies for reference.
Bob
On Mon, 19 Jun 2000 07:26:13 -0700, "Tom Calhoun"
<tcal...@infosol-inc.com> wrote:
>
snipped previous reference
><snip>
>My '98 Chevy truck manual, door plate, glove box sticker give the GVWR and
>both GAWRs, but not the GCWR.
>
>Where can I find out the GCWR?
>
>Thanks, Tom
>
>
Tom Calhoun
>
>
> Tom
>
> My 97 GMC truck stickers identified the same information as yours. I
> have always obtained the GCWR from the GMC Trailering Guide for the
> model year in question. I would think that Chevy does the same. I
> don't know this to be true, but possibly your VIN(Vehicle
> Identification Number) could be taken to a dealer for information
> retrieval. The information associated with that VIN might include the
> GCWR. I would still think that a better possibility is the trailering
> guide. Maybe dealers keep back copies for reference.
>
I had previously asked the Chevy dealer if they had a "towing guide" and
they didn't know what I was talking about (neither did I, I guess). I'll ask
again about a trailering guide and see if that gets better results.
Tom
Dick
capability.
I happen to have an old brochure from Chevy for 1996. Under the
trailering data it gives a table of Max trailer/tongue weight and
another table giving GCWR.
For example it shows a C2500 with a 5.7L engine and 3.73 rear end is
rated for a trailer of 7000 lbs with a tongue weight of up to 850
pounds / or / a 5th wheel of 7000 lbs and kingpin up to 3000 lbs.
Same engine without reference to model type but with a 3.73 has a GCWR
of 12,000 lbs.
Same vehicle has a GVWR of 6200 lbs and payload of 2079.
Lots of confusing information to put together for specific models.
Dick
Robert Carr
After I told you that I got my GCWR value from the towing guide, well
not true. It came from the product brochure. Max trailer weights came
from the Towing Guide. Sorry.
If you have a 98 Chevy truck, I would be very surprised if the GCWR
values are any different than a 97 GMC truck. For your info:
4.3 L V6
3.08 RAR=8500, 3.42 RAR= 9500, 3.73 RAR=10000
5.0L V8
3.08 RAR=9500 ,3.42 RAR=10500, 3.73 RAR=11500
5.7L V8
3.08 RAR=10000, 3.42 RAR=11000, 3.73 RAR=12000, 4.10 RAR=13500
7.4L V8
3.73 RAR=15000, 4.10 RAR=17000, 4.56 RAR=19000
Note: RAR = Rear axle gear ratio.
Bob
On Mon, 19 Jun 2000 12:37:16 -0700, "Tom Calhoun"
<tcal...@infosol-inc.com> wrote:
>
snipped previous reference
>>
Tom Calhoun
> Tom
>
> After I told you that I got my GCWR value from the towing guide, well
> not true. It came from the product brochure. Max trailer weights came
> from the Towing Guide. Sorry.
>
> If you have a 98 Chevy truck, I would be very surprised if the GCWR
> values are any different than a 97 GMC truck. For your info:
>
> 4.3 L V6
>
> 3.08 RAR=8500, 3.42 RAR= 9500, 3.73 RAR=10000
>
> 5.0L V8
>
> 3.08 RAR=9500 ,3.42 RAR=10500, 3.73 RAR=11500
>
> 5.7L V8
>
> 3.08 RAR=10000, 3.42 RAR=11000, 3.73 RAR=12000, 4.10 RAR=13500
>
> 7.4L V8
>
> 3.73 RAR=15000, 4.10 RAR=17000, 4.56 RAR=19000
>
> Note: RAR = Rear axle gear ratio.
>
> Bob
Thanks Bob,
I called the dealer's parts dept. and they were as clueless about a
trailering guide as they were about a towing guide.
I guess I should've bought a GMC <g>.
Tom
Jazz
glsu...@usa.net wrote:
> Outstanding explanation below of the GCWR. And to further point out,
> the Dodge Ram sales brochure says (in the very fine print at the
> bottom of the tow ratings table) something to the effect that these
> numbers are for "acceptable performance". The actual definition of
> acceptable performance is left to the purchaser.
>
> I recently picked up a trailer that was rated at the manufacturer as
> "8968 lbs dry weight." I found that my Ram will pull it acceptably
> (to me) at 55 mph (2250 rpm) in drive with the capablity to accelerate
> well into the 80s in overdrive if I need it to. This was a trip from
> Benson Arizona to Norfolk, Virginia. The truck downshifted a total of
> twice at 45 mph (1500 rpm) and dropped to 40 mph on one hill coming
> out of Las Cruces, New Mexico. That is "acceptable performance" to
> me.
Was 40 mph acceptable to the guy in the MH coming up behind you? <g>
I've never been on a hill with my class C (11,600# plus 2530# toad) that
dragged me down below 50 mph in 3rd gear. And BTW we have been thru Las
Cruces.....
Jazz
> Just look in their sales brochures. Most all have tables of towing
> capability.
>
> I happen to have an old brochure from Chevy for 1996. Under the
> trailering data it gives a table of Max trailer/tongue weight and
> another table giving GCWR.
>
> For example it shows a C2500 with a 5.7L engine and 3.73 rear end is
> rated for a trailer of 7000 lbs with a tongue weight of up to 850
> pounds / or / a 5th wheel of 7000 lbs and kingpin up to 3000 lbs.
>
> Same engine without reference to model type but with a 3.73 has a GCWR
> of 12,000 lbs.
>
> Same vehicle has a GVWR of 6200 lbs and payload of 2079.
>
> Lots of confusing information to put together for specific models.
>
> Dick
>
Well, it does tell you that if you really want to tow a 7000# trailer
that your tow vehicle can't weigh (including cargo) more than 5000# but
if you load it up to its GVWR of 6200# you can only tow a 5800# trailer.
This is what I have tried to point out to people who think they can tow
a 6000# or more trailer because it is rated for 7000# tow. Ain't gonna
work if you carry more than yourself and your backpack in the tow
vehicle.
Jazz
otiu...@worldnet.att.net wrote:
> GCWR has nothing to do with how your engine will handle the load. It
> relates to the capacity of your axles. If you exceed the GCWR either per
> a
> specific axle or overall, you are in danger of breaking an axle (or
> other
> wheel componetry i.e. suspension members, over taxing break system etc.).
> Needless-to-say, it could be both expensive and very dangerous to life
> and
> limb!
>
> Ken Creary wrote:
>
> > I'm pretty sure I understand the manufacturer specifications for GVWR
> > and GCWR and how to figure the max weight trailer for a specific
> > vehicle. What I'd like to understand better is the meaning of the
> > number. If I'm driving a vehicle loaded at the GCWR, does that mean the
> > engine can comfortably pull that load up hills or does it mean I should
> > jettison cargo and passengers to make it up the grade?
> > Thanks!
> > Ken
not true. GCWR is kinda arbitrary, as a matter of fact, and the
manufacturer can fudge with it if he wants to. And some (Dodge, maybe???
do.)
Greg Surratt
>Was 40 mph acceptable to the guy in the MH coming up behind you? <g>
>I've never been on a hill with my class C (11,600# plus 2530# toad) that
>dragged me down below 50 mph in 3rd gear. And BTW we have been thru Las
>Cruces.....
It was two lanes each direction, so he shouldn't have had a problem.
And I did pass a semi going up that grade.
And I did most of the trip at 55-60 in the right lane. No big ugly
truckers or anybody else walked up to me while I was getting fuel or
having a meal and told me I should get my slow truck off the highway.
I didn't have a CB, so I don't know what they were saying behind my
back.
I could run with the big trucks, but my wife wouldn't let me. <G>
Greg