Post by Calaminty Jane on Jan 1, 2009 14:06:18 GMT -5
Technical information concerning the weight that trucks can pull and how to determine what that weight will be.
All to often the truck dealer says there truck will pull any trailer
on the market! Well, yes, but… not necessarily safely! Even an 8horse
power garden tractor will tow a loaded 3-horse trailer. (On flat
smooth level ground!)Try and stop it going down a hill though!
Now that I know the facts and weights, there are LOTS of overloaded
rigs on the road today!
Several years ago, I was towing to western Pennsylvania with my 1994
Chevy 1500 extended cab, long box and Hi-Tech Aeroequus 2-horse
bumper pull. The truck has a 12,000# Gross Combined Vehicle Weight
Rating.
The trailer weighs about 2,000# empty.
I had LOTS of gear with me besides my 2 hoses! 10 gallons of water, 6
bales of hay, 150# grain, cloths, food, drink and some guns / ammo
for doing some long range target practice on my friends woodchuck
population.
I figured that this would be the most I'd ever be traveling with, so
I decided to go to a truck stop and get the rig weighed. I was
figuring between 10,000 and 11,000 pounds. Much to my surprise, it
was 12,240#! No wonder I had trouble getting up Mount Pocono!
Recently, I just purchased a 2004 Chevy Silverado 3500 4 X 4 crew cab
with an 8' box with the heavy duty towing package and the Duramax
diesel / Allison automatic transmission.
Then I got a 2004 Silverado 2-horse side by side Gooseneck trailer
with 12' living quarters and a 5' mid tack section. Very similar, if
not smaller than many rigs you see on the road. To give you an idea
of the size, it's 27' on the floor, 8' wide and a little under 12' to
the top of the air conditioner.
Anyhow, the Chevy's got a Gross Vehicle Weight Rating of 11,400#.
(Total weight of the truck and it's contents and the weight on the
hitch)
The 5th wheel / gooseneck towing capacity is 14,600#
The Gross Combined Weight Rating (weight of truck, trailer, payload,
etc) is 22,000#
Front Gross Axle Weight Rating is 4,800#
Rear Gross Axle Weight Rating is 8,550#
Lots of numbers to work from!
I recently took a drive out to a truck stop to weigh the truck and
trailer.
Much to my surprise, I need a bigger truck! I thought that a 1-ton
dually was enough!
Previously, I weighed the truck at a salvage yard. It was 8360# with
a full tank of fuel.
At the truck stop with a full tank of fuel in the truck and a full
water tank, No horses, No hay, No grain and No saddles, etc. in the
trailer. Just the tack box and some food / cloths from a previous
trip.
Here's what the print out showed:
Front axle = 4720# (Whew! 80# to spare!)
Rear axle = 7120# (No problem! 1,430# to spare!)
Trailer axle = 6860# (No problem here either. Rated at 12,148#.)
Total = 18,700#
Ok here, now, lets add some horses!
Hmm?
(2) Saddle horses 2,200#
(2) Saddles with blankets, and all the tack = 100#
(8) Bales of hay and for a weeklong trip = 400#
Tack box with blankets, etc = 100#
Farriers tools, spare shoes, etc. 100#
7 days of feed = 60#
Fully stocked refrigerator and pantry = 100 #
Weeks worth of cloths for 2 people = 50#
2nd person = 175#
Ok, now were up to another 3285#
Total = 21,985#
Just made it! Makes you think about all the bigger horse trailers
out on the road!
Figure a similar trailer would a 3 or 4 horse slant.
With the 4-horse, add:
2,200# for the horses
100# for saddles, blankets and tack
350# for extra riders
500# for extra trailer length, stall dividers, etc.
If the group is going away for a time, they will be
needing "groceries" for their horses and themselves!
That will come up to over 25,135# which is well over the 22,000# GCWR
for this particular truck!
Note: You will notice that if you add up the GVWR (11,400#) and the
5th wheel / gooseneck towing capacity (14,600#) it comes to 26,000#
which is over the Gross Combined Weight Rating of the truck. This
4,000# difference is a margin of safety.
Unfortunately, many people will just add "air bags" or "helper
springs" or "torsion bars" if the rig "squats" from the gooseneck or
bumper pull trailer's weight. Unfortunately, when a truck "squats"
it's telling you that it is overloaded in one way or another. Yes,
these will add to the "carrying capacity" of the vehicle, but do not
take into consideration the engine / transmission being to pull the
vehicle up a hill or the brakes being able to stop it when you go
down the other side!
Believe it or not your truck / trailer capacity is partially, based
on the "weakest link", your tires!
If you look at the sidewall, it will say such and such pounds at such
and such PSI. Multiply that by the number of tires and that is the
total capacity of the truck and trailer together. For safety reasons,
particularly during hot weather, it is advisable to run at least 10%
below the rated weight capacity of the tires.
Taking into consideration the "weakest link" if you put stronger
tires on, can the truck or trailer suspension carry the extra weight?
Your trailer's axles will typically have a weight capacity stamped on
them. Your truck will have a sticker on the driver's side door
stating the capacity of each axle.
Now, taking into consideration the trucks springs, engine,
transmission and brakes, your drivers side door or door pillar will
have a sticker with various ratings on it. Your owners manual and
also the truck dealers brochure will also have ratings / towing
capacities.
For the most part, what you want is the GCWR or Gross Combined Weight
Rating of the truck. This is the rating of the total weight of the
truck and trailer FULLY LOADED.
At this weight, your truck will be able to travel up any hill in the
USA, accelerate to pass vehicles and stop safely. This is lower than
the "tire capacity" of the truck /trailer. If you go over the GCWR,
safety, performance and longevity of the truck can be compromised.
Weight to horsepower ratio is a strong selling point when it comes to
sports cars. Basically it is the engines horsepower compared to the
weight of the vehicle. Say a 3000# sports car with a 300 horsepower
engine gives you a 10 to 1 ratio. (10# per horsepower) In other
words, that baby's gonna fly!
However, when it comes to trucks and trailers, the best you can hope
for is a "Drag'N Fly" rig, meaning that you will "drag" up one side
of the hill and "fly" down the other! For my rig, 22,000# and 300
horsepower, it works out to 73# / horsepower.
Having an underrated engine puts a great deal of extra strain on it.
Whenever you keep the "pedal to the metal", it creates the biggest
explosion in the engines combustion chamber it is capable of. This
explosion creates a great deal of heat and internal forces within the
engine. The longer you hold the excelerator down, the more heat
builds up which on a hot day can cause over heating. Engine oil
temperature can quickly rise to 350 degrees! You can fry chicken in
that!
Adding and auxiliary engine oil cooler can help by reducing the oil
temperature by 50 degrees or more. The new synthetic lubricants stand
up much better than conventional oils at high temperatures and heavy
loads. Still, the problem is that the engine is over loaded. Having
an extra 25 horsepower can equate to being able to pull a hill at
55mph vs. 50mph.
With regards to transmissions, particularly automatics, they can be
prone to overheating due to slippage of the clutches or torque
converter during shifting or excessive loads.
Transmission fluid typically runs through your engines radiator
through a separate cooling circuit. Excessive transmission fluid
temperature, not only breaks down the fluid, but can also cause your
radiator to boil over. If you pull the dip stick and it has a dark
color or burned smell, it should be replaced immediately and your
transmission should be checked. You can pick up a quart of fluid at
your local auto parts store to compare it to new fluid.
Automatic transmissions can be modified by adding a "shift kit" which
increases the fluid pressure to the clutches and also a "Heavy Duty
Clutch Pack" which decreases the chance of slippage by increases the
surface area of the clutches by using 1 or more clutch plates in the
same amount of space as the stock unit would take up.
To help save your transmission, avoid hard excelleration when your
transmission is shifting. When starting out use only a little
throttle until the vehicle gets moving, then excellerate from there.
Many of the newer automatics are equipped with overdrive. In
overdrive, the crankshaft of the engine will turn slower than the
driveshaft (not the rear axle). This increases efficiency since the
engine can run at a slower speed, relative to the speed you are
driving. The compromise is that at this lower engine speed, both
horsepower and torque which is the engines ability to pull a load is
decreased.
For the most part, you should avoid using overdrive when towing a
trailer. If you are on a nice open straight level area, you may be
able to get away with using it at speeds of 65 miles per hour. A good
way to tell if you are ok with using overdrive is if the transmission
doesn't down shift even if you go up some rolling hills. (50 to 100'
elevation changes).
Gear ratios are expressed as number such as 3.42, 4.10, etc. What
this means is that the drive shaft coming out of your transmission
will turn that many times for every turn of your rear axle.
Axle gear ratios can be compared to a fulcrum or seesaw. For
instance, put a 200# weight on a see saw. Put the fulcrum / pivot
point exactly in the middle and it will take 200# of force on the
opposite end to raise that weight off the ground. Lets say that's
equal to a 3.42 axle ratio. Now move the fulcrum closer to the
weighted end. This will give more "leverage" (4.10 axle) and require
less downward force to lift the 200# weight. The compromise is that
the engine will have to turn a little faster (about 200 RPM) to
maintain the same speed, therefor decreasing fuel efficiency. Yes,
you don't have to put the throttle down as far, however you still
need to fill each combustion chamber with fuel each time the engine
makes one revolution.
Torque and horsepower go hand and hand with one another. Think of
torque as the force required to get a load moving and horsepower
being the force required to keep it moving. On an 8-Horse hitch, the
2 wheel horses provide the "torque" and the other 6 keep the load
moving!
A properly set up truck and trailer should be able to make it up most
interstate highway hills at highway speeds without having to put
the "pedal to the metal". If you do find yourself in that situation,
it is better shift to a lower gear (manual or automatic transmission)
and maintain a steady RPM (revolutions per minute) at a range where
you get peek torque and horsepower. That information is usually in
the dealer's brochure for your particular vehicle. It usually has (2)
curves. One shows horsepower and one shows torque. At the RPM where
the two curves cross is where you can get the most output from your
engine. If you come to a long steep hill, pick a gear where you can
go as fast as possible (within the speed limit!) at about ½ to ¾
throttle and maintain that RPM. If you can only do 45mph on a 55mph
hill, just get over to the right hand lane and put on your flashers!
It's allot easier than calling a tow truck down the road!
To get some real numbers to work with, it is advisable to get your
tow vehicle weighed with out your trailer attached first, then with
the trailer. Check out www.catscale.com/ to find a local truck
stop with a scale. The fee is minimal.
By doing so, you will get a weight on each of your trucks axles. Then
go back and get weighed again with your trailer attached and you will
get a higher reading on your trucks axles. (Just bring along some
wheel chocks, unhitch, get weighed, rehitch and weigh again so you
don't have to make two trips.) Whatever the difference is, is the
weight on the hitch. (Bumper pull or gooseneck). Most trucks will
have a bumper pull and a gooseneck / 5th wheel hitch rating in the
owners manual. You can also contact the vehicles manufacturere.
Also, in states such as New Jersey, regulations require that even if
you are not a commercial carrier, your tow vehicle needs to be
registered for the COMBINED weight of the fully loaded truck and
trailer. Also, on a federal level, if the total weight is over
26,000#, a commercial drivers license is required.
Getting your rig weighed can help save a lot of heartache / expenses
in the long run and possibly even your life!
All to often the truck dealer says there truck will pull any trailer
on the market! Well, yes, but… not necessarily safely! Even an 8horse
power garden tractor will tow a loaded 3-horse trailer. (On flat
smooth level ground!)Try and stop it going down a hill though!
Now that I know the facts and weights, there are LOTS of overloaded
rigs on the road today!
Several years ago, I was towing to western Pennsylvania with my 1994
Chevy 1500 extended cab, long box and Hi-Tech Aeroequus 2-horse
bumper pull. The truck has a 12,000# Gross Combined Vehicle Weight
Rating.
The trailer weighs about 2,000# empty.
I had LOTS of gear with me besides my 2 hoses! 10 gallons of water, 6
bales of hay, 150# grain, cloths, food, drink and some guns / ammo
for doing some long range target practice on my friends woodchuck
population.
I figured that this would be the most I'd ever be traveling with, so
I decided to go to a truck stop and get the rig weighed. I was
figuring between 10,000 and 11,000 pounds. Much to my surprise, it
was 12,240#! No wonder I had trouble getting up Mount Pocono!
Recently, I just purchased a 2004 Chevy Silverado 3500 4 X 4 crew cab
with an 8' box with the heavy duty towing package and the Duramax
diesel / Allison automatic transmission.
Then I got a 2004 Silverado 2-horse side by side Gooseneck trailer
with 12' living quarters and a 5' mid tack section. Very similar, if
not smaller than many rigs you see on the road. To give you an idea
of the size, it's 27' on the floor, 8' wide and a little under 12' to
the top of the air conditioner.
Anyhow, the Chevy's got a Gross Vehicle Weight Rating of 11,400#.
(Total weight of the truck and it's contents and the weight on the
hitch)
The 5th wheel / gooseneck towing capacity is 14,600#
The Gross Combined Weight Rating (weight of truck, trailer, payload,
etc) is 22,000#
Front Gross Axle Weight Rating is 4,800#
Rear Gross Axle Weight Rating is 8,550#
Lots of numbers to work from!
I recently took a drive out to a truck stop to weigh the truck and
trailer.
Much to my surprise, I need a bigger truck! I thought that a 1-ton
dually was enough!
Previously, I weighed the truck at a salvage yard. It was 8360# with
a full tank of fuel.
At the truck stop with a full tank of fuel in the truck and a full
water tank, No horses, No hay, No grain and No saddles, etc. in the
trailer. Just the tack box and some food / cloths from a previous
trip.
Here's what the print out showed:
Front axle = 4720# (Whew! 80# to spare!)
Rear axle = 7120# (No problem! 1,430# to spare!)
Trailer axle = 6860# (No problem here either. Rated at 12,148#.)
Total = 18,700#
Ok here, now, lets add some horses!
Hmm?
(2) Saddle horses 2,200#
(2) Saddles with blankets, and all the tack = 100#
(8) Bales of hay and for a weeklong trip = 400#
Tack box with blankets, etc = 100#
Farriers tools, spare shoes, etc. 100#
7 days of feed = 60#
Fully stocked refrigerator and pantry = 100 #
Weeks worth of cloths for 2 people = 50#
2nd person = 175#
Ok, now were up to another 3285#
Total = 21,985#
Just made it! Makes you think about all the bigger horse trailers
out on the road!
Figure a similar trailer would a 3 or 4 horse slant.
With the 4-horse, add:
2,200# for the horses
100# for saddles, blankets and tack
350# for extra riders
500# for extra trailer length, stall dividers, etc.
If the group is going away for a time, they will be
needing "groceries" for their horses and themselves!
That will come up to over 25,135# which is well over the 22,000# GCWR
for this particular truck!
Note: You will notice that if you add up the GVWR (11,400#) and the
5th wheel / gooseneck towing capacity (14,600#) it comes to 26,000#
which is over the Gross Combined Weight Rating of the truck. This
4,000# difference is a margin of safety.
Unfortunately, many people will just add "air bags" or "helper
springs" or "torsion bars" if the rig "squats" from the gooseneck or
bumper pull trailer's weight. Unfortunately, when a truck "squats"
it's telling you that it is overloaded in one way or another. Yes,
these will add to the "carrying capacity" of the vehicle, but do not
take into consideration the engine / transmission being to pull the
vehicle up a hill or the brakes being able to stop it when you go
down the other side!
Believe it or not your truck / trailer capacity is partially, based
on the "weakest link", your tires!
If you look at the sidewall, it will say such and such pounds at such
and such PSI. Multiply that by the number of tires and that is the
total capacity of the truck and trailer together. For safety reasons,
particularly during hot weather, it is advisable to run at least 10%
below the rated weight capacity of the tires.
Taking into consideration the "weakest link" if you put stronger
tires on, can the truck or trailer suspension carry the extra weight?
Your trailer's axles will typically have a weight capacity stamped on
them. Your truck will have a sticker on the driver's side door
stating the capacity of each axle.
Now, taking into consideration the trucks springs, engine,
transmission and brakes, your drivers side door or door pillar will
have a sticker with various ratings on it. Your owners manual and
also the truck dealers brochure will also have ratings / towing
capacities.
For the most part, what you want is the GCWR or Gross Combined Weight
Rating of the truck. This is the rating of the total weight of the
truck and trailer FULLY LOADED.
At this weight, your truck will be able to travel up any hill in the
USA, accelerate to pass vehicles and stop safely. This is lower than
the "tire capacity" of the truck /trailer. If you go over the GCWR,
safety, performance and longevity of the truck can be compromised.
Weight to horsepower ratio is a strong selling point when it comes to
sports cars. Basically it is the engines horsepower compared to the
weight of the vehicle. Say a 3000# sports car with a 300 horsepower
engine gives you a 10 to 1 ratio. (10# per horsepower) In other
words, that baby's gonna fly!
However, when it comes to trucks and trailers, the best you can hope
for is a "Drag'N Fly" rig, meaning that you will "drag" up one side
of the hill and "fly" down the other! For my rig, 22,000# and 300
horsepower, it works out to 73# / horsepower.
Having an underrated engine puts a great deal of extra strain on it.
Whenever you keep the "pedal to the metal", it creates the biggest
explosion in the engines combustion chamber it is capable of. This
explosion creates a great deal of heat and internal forces within the
engine. The longer you hold the excelerator down, the more heat
builds up which on a hot day can cause over heating. Engine oil
temperature can quickly rise to 350 degrees! You can fry chicken in
that!
Adding and auxiliary engine oil cooler can help by reducing the oil
temperature by 50 degrees or more. The new synthetic lubricants stand
up much better than conventional oils at high temperatures and heavy
loads. Still, the problem is that the engine is over loaded. Having
an extra 25 horsepower can equate to being able to pull a hill at
55mph vs. 50mph.
With regards to transmissions, particularly automatics, they can be
prone to overheating due to slippage of the clutches or torque
converter during shifting or excessive loads.
Transmission fluid typically runs through your engines radiator
through a separate cooling circuit. Excessive transmission fluid
temperature, not only breaks down the fluid, but can also cause your
radiator to boil over. If you pull the dip stick and it has a dark
color or burned smell, it should be replaced immediately and your
transmission should be checked. You can pick up a quart of fluid at
your local auto parts store to compare it to new fluid.
Automatic transmissions can be modified by adding a "shift kit" which
increases the fluid pressure to the clutches and also a "Heavy Duty
Clutch Pack" which decreases the chance of slippage by increases the
surface area of the clutches by using 1 or more clutch plates in the
same amount of space as the stock unit would take up.
To help save your transmission, avoid hard excelleration when your
transmission is shifting. When starting out use only a little
throttle until the vehicle gets moving, then excellerate from there.
Many of the newer automatics are equipped with overdrive. In
overdrive, the crankshaft of the engine will turn slower than the
driveshaft (not the rear axle). This increases efficiency since the
engine can run at a slower speed, relative to the speed you are
driving. The compromise is that at this lower engine speed, both
horsepower and torque which is the engines ability to pull a load is
decreased.
For the most part, you should avoid using overdrive when towing a
trailer. If you are on a nice open straight level area, you may be
able to get away with using it at speeds of 65 miles per hour. A good
way to tell if you are ok with using overdrive is if the transmission
doesn't down shift even if you go up some rolling hills. (50 to 100'
elevation changes).
Gear ratios are expressed as number such as 3.42, 4.10, etc. What
this means is that the drive shaft coming out of your transmission
will turn that many times for every turn of your rear axle.
Axle gear ratios can be compared to a fulcrum or seesaw. For
instance, put a 200# weight on a see saw. Put the fulcrum / pivot
point exactly in the middle and it will take 200# of force on the
opposite end to raise that weight off the ground. Lets say that's
equal to a 3.42 axle ratio. Now move the fulcrum closer to the
weighted end. This will give more "leverage" (4.10 axle) and require
less downward force to lift the 200# weight. The compromise is that
the engine will have to turn a little faster (about 200 RPM) to
maintain the same speed, therefor decreasing fuel efficiency. Yes,
you don't have to put the throttle down as far, however you still
need to fill each combustion chamber with fuel each time the engine
makes one revolution.
Torque and horsepower go hand and hand with one another. Think of
torque as the force required to get a load moving and horsepower
being the force required to keep it moving. On an 8-Horse hitch, the
2 wheel horses provide the "torque" and the other 6 keep the load
moving!
A properly set up truck and trailer should be able to make it up most
interstate highway hills at highway speeds without having to put
the "pedal to the metal". If you do find yourself in that situation,
it is better shift to a lower gear (manual or automatic transmission)
and maintain a steady RPM (revolutions per minute) at a range where
you get peek torque and horsepower. That information is usually in
the dealer's brochure for your particular vehicle. It usually has (2)
curves. One shows horsepower and one shows torque. At the RPM where
the two curves cross is where you can get the most output from your
engine. If you come to a long steep hill, pick a gear where you can
go as fast as possible (within the speed limit!) at about ½ to ¾
throttle and maintain that RPM. If you can only do 45mph on a 55mph
hill, just get over to the right hand lane and put on your flashers!
It's allot easier than calling a tow truck down the road!
To get some real numbers to work with, it is advisable to get your
tow vehicle weighed with out your trailer attached first, then with
the trailer. Check out www.catscale.com/ to find a local truck
stop with a scale. The fee is minimal.
By doing so, you will get a weight on each of your trucks axles. Then
go back and get weighed again with your trailer attached and you will
get a higher reading on your trucks axles. (Just bring along some
wheel chocks, unhitch, get weighed, rehitch and weigh again so you
don't have to make two trips.) Whatever the difference is, is the
weight on the hitch. (Bumper pull or gooseneck). Most trucks will
have a bumper pull and a gooseneck / 5th wheel hitch rating in the
owners manual. You can also contact the vehicles manufacturere.
Also, in states such as New Jersey, regulations require that even if
you are not a commercial carrier, your tow vehicle needs to be
registered for the COMBINED weight of the fully loaded truck and
trailer. Also, on a federal level, if the total weight is over
26,000#, a commercial drivers license is required.
Getting your rig weighed can help save a lot of heartache / expenses
in the long run and possibly even your life!