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Old 01-28-2016, 09:59 AM   #43
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Originally Posted by Scottybdivin View Post
Got it. And with only 2 axles. That's impressive.
It is impressive. Our tag axle with 22.5 tires is only rated at 10,000. Must be duals.

I know they make them because a friend has a Newmar 5er with dual tires on the axles.
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Old 01-28-2016, 12:01 PM   #44
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Originally Posted by Scottybdivin View Post
Got it. And with only 2 axles. That's impressive.

Going to MorRyde in May to have the 2" spacer added so the RV rides more level. Will be changing out the rubber springs to the 9k or some other method to add capacity since after raising the RV 2" i will have about 8,500# on each axle. Plenty of tire capacity still with 4,806# per tire available.
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Old 02-27-2016, 05:25 PM   #45
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Originally Posted by JIMNLIN View Post
No wonder your confused.
Fifth wheel street has a poor weights calculator as it calculates numbers from a GCWR which is not on any truck.

It also ignores the trucks GAWR's/tire load ratings and particular the trucks RAWR/tire load ratings as it carries the load.
If you're referring the GCWR not being listed on the manufacturer's certification label, you are correct. But every manufacturer provides the GCWR for every tow vehicle and must be used for calculating one part of the trailer weight rating (TWR) per SAE J2807.

Another TWR calculation required by SAE J2807 is the GVWR (available payload). The GVWR is always less than the combined GAWRs, therefore, if the rear the GAWR is at max, the GVWR has already been exceeded in most, if not all, normal towing configurations.

RV Tow Check complies with both of these SAE J2807 TWR requirements.

All new vehicles equipped with OEM tires or better already meet or exceed the weight safety ratings. It's the vehicle owner's responsibility to ensure any aftermarket products meet or exceed the weight safety ratings. No calculator can enforce or ensure any vehicle is properly equipped.
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Old 02-27-2016, 08:11 PM   #46
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Another TWR calculation required by SAE J2807 is the GVWR (available payload). The GVWR is always less than the combined GAWRs, therefore, if the rear the GAWR is at max, the GVWR has already been exceeded in most, if not all, normal towing configurations.
Probably true with the older trucks but not with some of the new trucks with the high GVWR numbers. Looking at Rams body builders guide shows several trucks that may exceed its RAWR when using a GVWR based payload.

Example is a 2500 Ram 6.4 Hemi 10k GVWR with a 6k RAWR with a 3610 lb payload..
These trucks can weigh in the 3000 lb range on the rear axle. Now add a 3610 lb payload in the bed = 6610 lb load on the rear axle. Thats a 610 lb overload.

Another case is the infamous F150 HD 8200 GVWR and the 4800 RAWR and a 3200 lb payload claim. These trucks rear axle may weigh in the 2400-2500 lb range. Now add that 3200 lb payload Ford brags about in the bed = 5600 lb on the rear axle. Another overload

I see 2500 GM owners claiming their 10k GVWR trucks with a 6200 RAWR has 3400-3600 lb payload stickers. Same over load condition.
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Old 02-28-2016, 09:51 AM   #47
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Payload is a misnomer and can be very misleading. Payload is much like the towing capacity and is for a bare bones truck with a jockey driving. You can achieve the payload but most of the time you will exceed the GAWR on either the back or the front.
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Old 02-28-2016, 11:26 AM   #48
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Sad part is you need to grossly overestimate everything before you purchase.
Unless, of course, if you already have the truck and appropriate hitch. Then you could go test drive and weigh everything for calculations before you buy.


In a perfect world of course!
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Old 02-28-2016, 08:55 PM   #49
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Originally Posted by JIMNLIN View Post
Probably true with the older trucks but not with some of the new trucks with the high GVWR numbers. Looking at Rams body builders guide shows several trucks that may exceed its RAWR when using a GVWR based payload.

Example is a 2500 Ram 6.4 Hemi 10k GVWR with a 6k RAWR with a 3610 lb payload..
These trucks can weigh in the 3000 lb range on the rear axle. Now add a 3610 lb payload in the bed = 6610 lb load on the rear axle. Thats a 610 lb overload.
Okay, I concede. I admit that I used a poor example to relay the message I wanted to communicate.

Allow me to get it right. Letís get back to the GCWR and GVWR and the calculations that SAE J2087 uses to prevent the TWR from exceeding the GVWR or the GCWR.

BTW: If you havenít done so, I recommend you read question one on the FAQ page at the RV Tow Check website.

Use this real truck as an example from Ramís chart.

2016 Ram 2500, Crew cab, Short box, 4X2, 6.4 Hemi
GCWR: 19,800
GVWR: 10,000
Ft. GAWR: 5,500
Rr. GAWR: 6,000
Base Wt: 6,389
Base Ft. Axle Wt: 3,584
Base Rr. Axle Wt: 2,805
Payload: 3,610
TWR: 12,940

The formula that J2807 uses for GVWR in conjunction for calculating 5th Wheel TWR is (GVWR-TVTW)X5. The X5 is for calculating pin weight at 20%.

TVTW = (6,389+100+70+300) (Base Wt. + Cargo + Gooseneck hitch + Two people) This is the Ram standard for J2807 on this chart.

(10,000-6,859) X5= 15,705

In the above equation, the available payload (3,134) is multiplied by 5. As far as the rear GAWR, it will not be exceeded here. (3,134+2,805= 5,939)

Per your example (2,805+3,610), the rear GAWR would be exceeded by 415 pounds. The problem is, your example is not realistic because the published payload does not include any passengers, cargo and hitch weight.

J2807 has a second formula that must be used, and in between these two formulas, the least TWR must be used.

The second formula is GCWR-TVTW=TWR
19,800-6,859= 12,941

Therefore, between the two calculations, the least TWR that will be used is 12,941. (One pound more than the chart due to fractional numbers being rounded.)

RV Tow Check (RVTC) uses the same formulas as required by SAE J2807. Assuming that you noticed, RVTC uses the respected multiplier for the full range of 10% to 25% for 5th wheel and conventional pin/tongue weights. Additionally, RVTC allows users to enter realistic passenger, cargo and hitch weight to obtain realistic vehicle towing capacity (a.k.a, realistic TRW).
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Old 02-29-2016, 11:55 AM   #50
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TVTW = (6,389+100+70+300) (Base Wt. + Cargo + Gooseneck hitch + Two people) This is the Ram standard for J2807 on this chart.
Oops, I forgot to add an additional note. Even the engineers or writers at Ram make mistakes.

Ram notes hitch weights as follows:
Trailering Equipment Weight: 75 lb for Conventional Hitch, 70 lb for Gooseneck and 250 lb for 5th Wheel.

SAE J2807 typical aftermarket hitch weights are as follows:
70 lb for conventional hitch, 170 lb for gooseneck, 250 lb for 5th Wheel

Ram actually used 70 pounds for hitch weight in their calculations. I guess they dropped the 1 for the gooseneck hitch. As to why they use 70# hitch weight instead of the published 75# is anybody's guess (another typo?).
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