Term question re: weight calc/load estimate utility

[ramyankee]

Trying this out on my truck and 5th Wheel. There are a couple of terms I need a little explanation on. For both units they are asking for Steer axle and Drive axle. What are those? Are they found when I go to a scale? For the 5th Wheel they ask for Trailer axle weight. Would that be another term for my "advertised" dry weight?
Thanks for any help on there terms.

[xcntrk]

ramyankee wrote:
""""" As it says, trailers axle weight. Weight of the loaded trailer minus pin weight"""""
This was part of a reply I received.I think I understand this. Is it saying(an example here) that if the 5th Wheel is weighed at 9000# and the hitch weight is 2000# then the trailer axle weight is 7000#.
Thank you

Is that question with the Trailer Weight Calculations & Load Estimator Utility, or just a general question about trailer & axle weights? I for one am not following what you're asking.

But to help you with understanding trailer weights; they all start with the carrying capacity of the axles selected by the manufacture. Let's say a 5'er toy-hauler you're looking at is a tandem axle each rated at 7000# GAWR (aka 14k total). Everything is a subtraction from that load rating. So the base or dry weight of the trailer and all of its components subtracts from the axle rating, and what's left is the trailer payload. So let's say your trailer weighs 8500# dry with a GVWR of 13800# (aka based on the 14k# axle rating), that would leave you with a 5300# payload capacity for; toys, gear, fluids, food, etc, etc before maxing out the GVWR of the trailer.

The Trailer Weight Calculations & Load Estimator Utility is a tool where you can plug in your CAT scale measurements and it will report out information about your trailer in comparison to the manufacture specifications. It will tell you; how much your trailer weighs, what percentage of that weight is on the tongue or pin, and how much of that weight is on the trailer axles. For the trailer axle info, it will tell you how much of the scale measured weight is split between the two axles and even down the individual tire to help ensure your tire load ratings are sufficient. For bumper-drawn trailers, if you have WD scale measurements it will also tell you how much weight the WD is distribution across the TV and Trailer.

Hope this helps.

[ramyankee]

""""" As it says, trailers axle weight. Weight of the loaded trailer minus pin weight"""""
This was part of a reply I received.I think I understand this. Is it saying(an example here) that if the 5th Wheel is weighed at 9000# and the hitch weight is 2000# then the trailer axle weight is 7000#.
Thank you

[Old-Biscuit]

ramyankee......

Look for a 5th wheel with a GVWR of 12K (13k at most)
With that max weight you should be under all ratings.
You will enjoy the tow much more....the more you enjoy the tow the more you go :B

[JIMNLIN]

Our truck (by our sig) was weighed when we licensed it, fuel full, 6850#.

My 2wd 2500 Dodge/Cummins NV5600 2wd weighs in at 6880 lbs gross. My front axle weighs in at 4080 lbs and the rear at 2800 lbs.

Many 2wd 2500 GM owners report around 2700 lbs on the rear axle which leaves you with approx 3200-3300 lbs for a max payload.

You will be fine with that trail;er unless your gonna' carry a aux fuel tank and a gen set and lots of heavy extras.

[ramyankee]

To OB.....We already have an older unit but are trying to decide whether to upgrade as Patti retires around August next year. As you can see by my sig it is a "91"/"92" Road Ranger 32', Front LR 5th Wheel. LOVE this unit and not sure how worried we should be about a ~23 year old unit.
That being said, I am sort of trying to find out where we should go on size.
Our truck (by our sig) was weighed when we licensed it, fuel full, 6850#.
GCWR-----20000#
GVWR----- 9200#
FAGWR----- 4800#
RGAWR----- 6084#
Our present 5th Wheel
GVWR-----13890#
FGAWR----- 6000#
RGAWR----- 6000#
I know a person cannot rely on the "posted weights" but here they are
Dry------- 8114#
Hitch------ 1890#

The unit I would love from just looking at it would be the Arctic Fox 29K or 29-5T, with the 29K being TOO heavy on the hitch and the 5T being heavier than I want so we need to find a unit to fit into a fairly narrow window. Would like to stay lighter than what we have now. I know that size really does not make a big difference when you are pulling a non-streamlined brick down the road but we generally have run about 6mpg-7mpg. But most all our pulling has been in the Sierra's or going to Montana and back. There are those that think that mileage is way too low, BUT...We would like to be in the 28'-29' range. But all this is really for another forum. Sorry to have rambled. But now I have weights for my truck and 5th Wheel.
So thanks to all the info so far. This forum is always very informative and many of us really appreciate all the info.
APPRECIATED.

[Old-Biscuit]

Ron Gratz wrote:

Old-Biscuit wrote:
The difference in trucks rear axle weight when hooked up to 5vr and when NOT hooked to 5rv is the 5rvs 'Pin Weight'

Not unless the pin is directly over the rear axle.

In general, the pin weight will be equal to

(front axle + rear axle when hitched) - (front axle + rear axle unhitched)

This will account for any load added to front axle when pin is ahead of rear axle, or any load removed from front axle when pin is behind.

Ron

True that is more accurate way to figure pin weight.....

But very little weight (if any) is transferred to front axle even with hitch forward of rear axle center line........that is why RAWR/Rear Tire Load Capacity and the GVWR are so important with a 5th wheel.
Now if it's a pull behind trailer......different scenario

[Ron_Gratz]

Old-Biscuit wrote:
The difference in trucks rear axle weight when hooked up to 5vr and when NOT hooked to 5rv is the 5rvs 'Pin Weight'

Not unless the pin is directly over the rear axle.

In general, the pin weight will be equal to

(front axle + rear axle when hitched) - (front axle + rear axle unhitched)

This will account for any load added to front axle when pin is ahead of rear axle, or any load removed from front axle when pin is behind.

Ron

[Old-Biscuit]

More Info......

IF you don't have the 5th wheel and are trying to calculate what you can tow etc.

Get the truck weights (F/R axle)
The difference between trucks rear axle as weighed and the trucks RAWR will be the 'payload' available-------that will be trailers pin weight.
Keeping in mind the trucks rear tire MAX Load Rating at MAX PSI (on sidewall).
And the trucks GVWR

Then you have a starting point....
Look at the 5th wheels GVWR (on Data Plate) and using 20% of that number will give you a 'guesstimation' of what the 5vrs 'wet' pin weight would be.
Typically you want at least 20% pin weight for good towing..lighter pin weights can result in 'chucking' (Actual pin weights can be higher than 20% but it's a good 'guesstimate' number without actually weighing)

Example:
Truck weighs 7000# camp ready (you, passengers, any stuff in cab, hitch(200#), and fuel) Front axle----3800# Rear axle---3200#
Trucks RAWR is 6200#........so that leaves 3000# payload
Tires are rated at 3200#/each (6400# total)
Truck GVWR is 10,100#

Trailer GVWR is 12,000#
20% is 2400#

So truck has enough payload (3000#) for the 2400# pin wet
Trucks rear axle (Rated @ 6200#----weight is 3200+2400=5600) has enough capacity for the 2400# pin weight
Rear tires have enough load capacity at max psi (Rated @ 6400#----weight is 5600#) for the 2400# pin weight
Truck has enough GVWR (Rated @ 10,100#.....weight is 7000+2400=9400) for the 2400# pin weight

>>>>>>>>>>>>DISCLAIMER><<<<<<<<<<<<
The above is just an example of the math..numbers are made up to fit scenario
Real World numbers WILL be completely different

[NC_Hauler]

MOST EXCELLENT post, OB.....pretty much covered it all:B

[donn0128]

ramyankee wrote:
Trying this out on my truck and 5th Wheel. There are a couple of terms I need a little explanation on. For both units they are asking for Steer(front) axle and Drive (rear)axle. What are those? Are they found when I go to a scale? For the 5th Wheel they ask for Trailer axle weight. As it says, trailers axle weight. Weight of the loaded trailer minus pin weightWould that be another term for my "advertised" dry weight? A figmant of someones imagination. This number is calculated based on engineering calculations. Not really worth a hoot except for something to put in the brochure in an attempt to sell unsuspecting people more trailer than their tow vehicle can handle.
Thanks for any help on there terms.

Based on the little information you have provided, I assume you have a 2500HD? That being said, you need to load it up like your going camping and drive to the scales. To that number add 250 pounds for a hitch, 350 pounds if you need a slider hitch. Now, look on the drivers door post for the factory published GVWR 9200 for a 2500HD and 9900 for a 3500 SRW. Subtract your scaled weight from that number. That is how much weight you can add to the truck before you exceed the manufacturers numbers.
Back when I foolishly bought a Chevy 2500HD D/A it scaled ready to travel at 7500 pounds. Meaning I had about 1700 pounds of payload. I suspect your numbers will be similar.
To make a best guess estimate for what fifth wheel you can tow, use 20% of the fivers GVWR as pin weight. In reality a 10,000 GVWR fifth wheel will have a pin weight around 2000 pounds. Does this make sense now?

[Old-Biscuit]

Truck has a 'Steer Axle' (That's the Front axle) and a 'Drive Axle' (That would be the Rear Axle)

5th wheel only has Trailer Axle. Forget that 'advertised dry weight'.

When you go to scales you will want to get two complete weigh ins.

1st weigh in...

Drive truck with trailer hooked up onto scales (3 separate platforms)
Truck front axle on front one
Truck rear axle on center one
Trailer axles on rear one

Tell scale operator you are 'private'...they will weigh combo and then you pull off scales.
Go to back of parking lot and drop 5th wheel.
Go back onto scales with truck front axle on forward platform and rear axle on center on.
Tell scale operator.........'private-reweigh'.
They will weigh. Pull off scales.....go park and go inside to get weigh tickets.

One will have the truck Front/Rear Axle weight and the trailer axle weight
The other one will have truck F/R axle weights.


You then have ALL the weight numbers to figure out:
Weight on truck F/R axles hooked up to 5vr
The 5vrs axle weight when hooked up to truck
The truck/trailer combo total weight
Weight on truck F/R axles when NOT hooked to 5vr...plus trucks total weight

The difference in trucks rear axle weight when hooked up to 5vr and when NOT hooked to 5rv is the 5rvs 'Pin Weight'

The 5rvs pin weight plus trailers axle weight will be the 5vrs total weight.

You can then compare the various weight numbers to your trucks axle ratings, tire load ratings, GVWR, trailers GVWR and the trucks GCWR

FAWR.....front axle weight rating
RAWR.....rear axle weight rating
GVWR.....gross vehicle weight rating
GCWR.....gross combined weight rating

Ratings will be on door jam sticker, on trailers VIN Data Plate and on sidewall of tires.

EDIT: Spelling...lack of some letters in words----keyboards fault :S

[crabbin_cabin]

Try this - truck - front axle = "steer" and rear axle = "drive". Trailer axle weight is as it is. But your trailer wheels/axles should be equal from left and right and the front pair and rear pair should also be equal.
Perfectly clear??