โFeb-17-2015 10:35 AM
โFeb-20-2015 04:03 AM
โFeb-19-2015 09:34 PM
โFeb-19-2015 07:37 PM
โFeb-19-2015 06:18 PM
JIMNLIN wrote:op wrote:
Now weโll look at the trailer weight of 16184.
Fifth Wheel -
Potential PW @20% is 3237
PW (3237) + GVW (6616) = Loaded GVW (9853) (Under GVWR: 10000)
PW (3237) + Rear Axle Weight (2581) = Loaded RAW (5818) (Under RAWR: 6000)
You've dropped some figures in your calculations.
Trucks base rear axle weight is 2581 lbs. Now add 250 lbs for the hitch and 170 lbs (50 percent of occupants on the rear axle) = 3001 lbs. Now add the 3237 lb pin weight = 6238 lbs on the rear axle. The truck is over the 6000 RAWR.
At this point air bags/18" 3500 lb rated tires and wheel will have to be added.
Now lets hope the hitch isn't a 22% which a many are. The 22% = a 3560 lb pin weight.
Like we tell folks its best to get some actual scaled front and rear axle weights and use the GVWR or RAWR method. Both are safe.
That way we won't be telling anyone the 2500 Ram Hemi can tow a 16184 lb 5th wheel.
โFeb-19-2015 05:52 PM
DW-gray wrote:kzspree320 wrote:
Fifth Wheel -
Potential PW @20% is 3237
PW (3237) + GVW (6616) = Loaded GVW (9853) (Under GVWR: 10000)
PW (3237) + Rear Axle Weight (2581) = Loaded RAW (5818) (Under RAWR: 6000)
It looks like your rear axle weight does not include the weight of the fifth wheel hitch or passengers. It's clear your GVWR does, but some weight has to be added to the empty weight of rear axle and pin weight to accomodate these items. I suspect your loaded RAW is closer to 6200 lbs with a 200 lb hitch and about half of 340 passenger weight. That would put if over a 6,000 RAWR. What am I missing??
Well how about that. You pointed out a potential flaw. That's the closet I've seen. So now what can be done about it? What do you recommend to fix this flaw?
Keep in mind, getting scaled axle weight from a dealer is probably not going to happen. Some salespeople don't even know where to find such information. It may be very difficult to get the best weight information. Searching for that info at some manufacturer's websites can be very difficult. Then there is this question, will the trailer's pin weight be 20%? If it turns out to be only 17%, then he would be in much better position.
So lets talk about how to improve a calculator that only accepts GCWR, GVWR, GVW, the hitch, passenger weight, and cargo weight and not add any other entries.
The mission is K.I.S.S. Keep It Simply Safe and easy to use.
โFeb-19-2015 05:07 PM
op wrote:
Now weโll look at the trailer weight of 16184.
Fifth Wheel -
Potential PW @20% is 3237
PW (3237) + GVW (6616) = Loaded GVW (9853) (Under GVWR: 10000)
PW (3237) + Rear Axle Weight (2581) = Loaded RAW (5818) (Under RAWR: 6000)
โFeb-19-2015 04:45 PM
kzspree320 wrote:
Fifth Wheel -
Potential PW @20% is 3237
PW (3237) + GVW (6616) = Loaded GVW (9853) (Under GVWR: 10000)
PW (3237) + Rear Axle Weight (2581) = Loaded RAW (5818) (Under RAWR: 6000)
It looks like your rear axle weight does not include the weight of the fifth wheel hitch or passengers. It's clear your GVWR does, but some weight has to be added to the empty weight of rear axle and pin weight to accomodate these items. I suspect your loaded RAW is closer to 6200 lbs with a 200 lb hitch and about half of 340 passenger weight. That would put if over a 6,000 RAWR. What am I missing??
โFeb-19-2015 03:15 PM
GCWR >= TV + TT + all cargo/hitch/etc
โFeb-19-2015 02:35 PM
โFeb-19-2015 01:28 PM
JIMNLIN wrote:So far you haven't proved that calculators that don't include GAWR fail. Since the calculator discussion has been mostly about RV Tow Check, prove to me, and everyone else, the flaws in RV Tow Check with the following data from real tow vehicles that may tow fifth wheel or conventional trailers.
I've ran the numbers and have posted the results above. This calculator has been around for a while and has been on other RV forums. Reviews of its accuracy were about like we see on rv.net. Not much good was said about it.
However your asking for numbers that have nothing to do with what I have said or what the calculator asks for.
These are the numbers straight out of the '15 Ram Body Builders spec sheets PDF for a 2500 Ram 6.4 hemi 5500 FAWR/6000 RAWR the calculator asks for and the same numbers I used in my above reply;
...22800 GCWR..
...10000 GCWR
...6026 gvw
I added
...250 gear/hitch
...340 passenger
calculator says the 2500 Ram can tow a 16184 lb TT or 5th wheel.
Now do the GVWR math or the RAWR math on this truck and same trailer and either way a 16k trailer will overload the GVWR and/or the RAWR/tire capacities of the 2500 truck. Overloading a tire is illegal and dangerous.
This a a example of the fallacy of a calculator. In this case its basing a formula on GCWR calculator that omits the trucks #1 safety numbers (RAWR/tires/wheels/brakes and suspension capacities).
โFeb-19-2015 10:45 AM
So far you haven't proved that calculators that don't include GAWR fail. Since the calculator discussion has been mostly about RV Tow Check, prove to me, and everyone else, the flaws in RV Tow Check with the following data from real tow vehicles that may tow fifth wheel or conventional trailers.
โFeb-19-2015 09:52 AM
โFeb-19-2015 09:44 AM
blt2ski wrote:
There you go! as I have been stating. The reason to go NOT go over the manufactures ratings are, handling, shortens the life of the vehicle, ALONG WITH as I have stated, warranty will and can be denied. THOSE are the reasons for NOT going over the manufactures ratings.
Marty
โFeb-19-2015 09:12 AM
JIMNLIN wrote:
Thanks for posting what GM says about not exceeding the front or REAR axle rating as it reinforces my point I've made that the calculator doesn't take in any of the GAWR's into consideration anywhere which leads to over loading the RAWR on "SOME" high GVWR vehicles with low RAWR numbers.GAWRs are not the primary function within Title 49 in consideration of braking, tire and rim capacity. Most anyplace where itโs written โGAWR,โ it refers to the sum of GAWRs should not be less than GVWR. GVWR is the supreme rating regardless of the sum of GAWRs.
Title 49 says hundreds of tech things but nowhere does it say that GVWR is supreme over the GAWRs.
Tire and rim capacity are selected by the vehicles GAWR if you take the time and read 571.110/.120 and has nothing to do with the trucks GVWR.
Brakes.....
NHTSA says this about components of the GAWR:
"Gross Axle Weight Rating is the rated load-carrying capacity of an individual axle and wheel assembly. (It represents the load that may be steadily sustained by the components in the system; i.e., tires, rims, hubs, bearing, axles, brakes, suspension, sub frame, etc. with the GAWR limited by the components with the lowest working rating"
or another source...
RMA (rubber manufacturers)
โข GAWR: Gross Axle Weight Rating (for each axle) -
The maximum weight rating that the components
(tires, rims/wheels, brakes, springs, and axle) of
each axle are designed to support. This is
determined by the lowest design capacity of any
component. In other words, if the wheels have the
lowest design capacity of any component on that
axle, installing tires with a higher load capacity
does not increase the GAWR. By regulation, the
tire load rating times the number of tires on that
axle must equal or exceed the GAWR for that axle.
and for a trailer.....
dexter axle;
The Gross Axle Weight Rating (GAWR) of your running gear is determined by the lowest rated component in the assembly. The capacity of the wheel, tire, axle, brake, springs/rubber and hub are all considered.