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uncle_bob · 05-30-2018, 07:35 AM

Hi

All this confusion with various numbers is what drives the whole "just look at the axle numbers" comments. They are the only thing that is rated the same way a CAT scale measures .... ( pounds on the ground )

Bob

suncoasteng · 06-11-2018, 06:59 AM

Sounds like you have too many personal possessions forward. We see this on boat trailers all the time - too much tongue weight. On a boat trailer, you can slide the boat backwards on the trailer, but not on an Airstream.

Start by moving the heavy stuff (spare tyre, jacks, canned food, dishes) aft of the rear axles and put the light stuff forward of the axles. Then weigh again. And where is your fresh water tank in relation to the trailer axles?
If aft, you can reduce tongue weight by filling that tank. If forward, you need to drain it

uncle_bob · 06-11-2018, 07:50 AM

Hi

The further back you move the weight in the trailer, the more likely you are to get into sway issues. Moving things from the front to the rear may take care of tongue weight and create other issues. Best bet ( if it is junk related ) is to start sorting out what you have and leaving more of it at home .... The simple answer is "you don't have the capacity to haul all that stuff ...".

Bob

Tireman9 · 06-11-2018, 02:21 PM

When you are done making adjustments and moving stuff around and get new scale readings. You need to look at tire loading and inflation.

Ideally, you would get the individual axle load as they are probably not split 50/50

You are also probably not 50/50 side to side loaded either. The good news is that you don't have slides or residential refrigerator so are probably 51/49 side to side or 48/52%

The best approach is to take the heavier loaded axle and assume a 52/48% split and compare the 52% number with the tire load capacity. You should have at least a 15% load capacity margin. (52% of heavier axle is no greater than 85% of tire max capacity.

Finally, with a multi-axles trailer you should use the tire sidewall pressure number as your "Cold Tire Inflation" to try and lower the Interply Shear forces that are trying to tear the tire belts off the carcass.

You can learn more on my RV tire blog.

Robertone139 · 06-18-2018, 10:24 AM

Hi,
This is Sabine, Robertone139's wife.
We actually had a different hitch installed now since the old one was worn in the joints. We opted for the Equalizer 1200# hitch since I can't afford the Hensley at the moment.

The installer did get a TW with a scale which was #900 under the jack and #800 under one side of the bars of the WD hitch. Then we went to the CAT scale again.
Results:
Jeep GC alone: Steer Axle 2980 lbs. (rated per door sticker 3200 lbs max.)
Drive Axle 2580 lbs. (rated per door sticker 3700 lbs max.)
Distribution ratio should be 54/46 F/R per Jeep which it is. (5560 lbs total 100%
2980 lbs front 53.6%
2580 lbs rear 46.4%)

Then we went on 3 pads. Steer axle 2800 lbs.

Drive axle 3480 lbs.

Trailer ax. 5000 lbs.
So the front and rear axle combined weight is 6280 lbs. now and the F/R distribution is off now. (2800 lbs. is 44.6% and 3480 lbs. is 55.4%). The steer axle is to light now in my opinion compared to the drive axle. We are still in the limits of the individual axle ratings but the ratio is off and we are worried it influences the driving/steering abilities of the jeep. Do you think we could balance it out by adjusting the Equalizer hitch to add more weight to the front/steer axle by adding more washers? Currently 5 washers and up to 8 can be applied. So to summarize when we hitch the trailer with the WD equalizer hitch we take 180 lbs off the front and add 900 lbs to the rear axle, so 720 lbs added to the Jeep from the trailer. The trailer weight was around 5800 lbs. by itself loaded. The Jeep had full tank of gas and my Robertone husband at 220 lbs. in it. The GVWR Jeep is 6800 lbs. and the Payload 1163 lbs. Calculations correct? Thanks in advance.

Robertone139's wife

uncle_bob · 06-19-2018, 08:07 AM

Quote:

Originally Posted by Robertone139

Hi,
This is Sabine, Robertone139's wife.
We actually had a different hitch installed now since the old one was worn in the joints. We opted for the Equalizer 1200# hitch since I can't afford the Hensley at the moment.

The installer did get a TW with a scale which was #900 under the jack and #800 under one side of the bars of the WD hitch. Then we went to the CAT scale again.
Results:
Jeep GC alone: Steer Axle 2980 lbs. (rated per door sticker 3200 lbs max.)
Drive Axle 2580 lbs. (rated per door sticker 3700 lbs max.)
Distribution ratio should be 54/46 F/R per Jeep which it is. (5560 lbs total 100%
2980 lbs front 53.6%
2580 lbs rear 46.4%)

Then we went on 3 pads. Steer axle 2800 lbs.

Drive axle 3480 lbs.

Trailer ax. 5000 lbs.
So the front and rear axle combined weight is 6280 lbs. now and the F/R distribution is off now. (2800 lbs. is 44.6% and 3480 lbs. is 55.4%). The steer axle is to light now in my opinion compared to the drive axle. We are still in the limits of the individual axle ratings but the ratio is off and we are worried it influences the driving/steering abilities of the jeep. Do you think we could balance it out by adjusting the Equalizer hitch to add more weight to the front/steer axle by adding more washers? Currently 5 washers and up to 8 can be applied. So to summarize when we hitch the trailer with the WD equalizer hitch we take 180 lbs off the front and add 900 lbs to the rear axle, so 720 lbs added to the Jeep from the trailer. The trailer weight was around 5800 lbs. by itself loaded. The Jeep had full tank of gas and my Robertone husband at 220 lbs. in it. The GVWR Jeep is 6800 lbs. and the Payload 1163 lbs. Calculations correct? Thanks in advance.

Robertone139's wife

Hi

The gotcha is that one washer may move a bit more weight than you really need to move. You might be over with another washer, you could still be under. Once you get "close" ( and everything is inside limits ) it's more about how things feel than the numbers.

Indeed putting about 200 more pounds on the front is a good idea and that would be worth doing. Drive the rig first and see how it does. Then put on the washer, measure things and see how that feels.

Bob

ROBERT CROSS · 06-19-2018, 09:37 AM

.....why the constant fretting about tongue weight?

I know our TW...1200lb on a Sherline, with the haha installed, loaded for camping.

Set for towing with WD set the receiver weight is 840lb, big difference from the TW. 😊

More importantly for us is the trailer axle weights, since AS thought two 3500lb axles would be great on a GVWR of 7300lb, and a CCC of 676. 😟

Bob
🇺🇸

suncoasteng · 06-20-2018, 07:01 PM

Quote:

Originally Posted by uncle_bob

Hi

The further back you move the weight in the trailer, the more likely you are to get into sway issues. Moving things from the front to the rear may take care of tongue weight and create other issues. Best bet ( if it is junk related ) is to start sorting out what you have and leaving more of it at home .... The simple answer is "you don't have the capacity to haul all that stuff ...".

Bob

Bob - have you ever pulled a trailer???? OP said they had 1140 pound tongue weight, they cant move enough stuff to get it to sway!

ITSNO60 · 06-20-2018, 07:23 PM

Quote:

Originally Posted by ROBERT CROSS

As noted above you need three weights..👍
TV alone.
TV & AS w/o WD.
TV & AS with WD set for travel, loaded for camping.

Bob
🇱🇷

Hi Robert, does your example indicate that your total tongue weight is 980 LBS? Just trying to figure out the math

ROBERT CROSS · 06-20-2018, 07:44 PM

Quote:

Originally Posted by ITSNO60

Hi Robert, does your example indicate that your total tongue weight is 980 LBS? Just trying to figure out the math

Our TW loaded for camping is 1200lb. Trailer un-hitched, loaded and LEVEL.😳

The weight on the receiver with WD set is 840lb.

Bob
🇺🇸

uncle_bob · 06-21-2018, 06:58 AM

Quote:

Originally Posted by suncoasteng

Bob - have you ever pulled a trailer???? OP said they had 1140 pound tongue weight, they cant move enough stuff to get it to sway!

Hi

I've apparently towed a lot more than you have if you believe that tongue weight tells the whole story. The Classic's have tongue weights that are all inside the magic percentages. They most certainly will sway if you don't put something on the rig to prevent it.

Bob

ITSNO60 · 06-21-2018, 06:46 PM

Quote:

Originally Posted by ROBERT CROSS

Our TW loaded for camping is 1200lb. Trailer un-hitched, loaded and LEVEL.😳

The weight on the receiver with WD set is 840lb.

Bob
🇺🇸

Thanks so when adding up payload for your TV which figure should be used, 1,200 or 840?

RandyNH · 06-22-2018, 05:24 AM

Quote:

Originally Posted by ITSNO60

Thanks so when adding up payload for your TV which figure should be used, 1,200 or 840?

When trying to calculate the true payload number it will actually end up somewhere between the two numbers. 1200 is the raw weight and the 840 is the net after the distribution (at the point of the hitch assembly only) the weight distribution part of the process means that the approx 360 lb difference must go somewhere, thus to the front and trailer axles, so if distributed evenly 180lb to each. So, 840 rear and 180 front totaling 1020lbs would be the hit against the vehicle payload.

This is why going to the CAT scale is so important, the front two axle readings are what your GVW is and should be compared against the vehicle GVWR not necessarily against what the stickered payload is, as these are your true numbers.

ROBERT CROSS · 06-22-2018, 06:15 AM

As Randy has noted.."payload" is only part of your concern.

I pay closer attention to how much of my TV axle and tire ratings I have left over when loaded for camping.

Loaded for camping the weight on our front TV axle is 3640lb with a rating of 4180lb....540lb wiggle room.👍
The rear is 4680lb with rating of 5500lb....820lb wiggle room.👍
Michelin LTX 'E' rated 3415lb ea.

The 2500 Suburban's 8.1L drivetrain is well up to the task.🤗

Bob
🇺🇸

Tireman9 · 06-22-2018, 08:30 AM

In the copy of AS Owner's Manual I have, it says they you need to know the side loading too not just the total on the axles.

This means you probably need to find a scale at a gravel pit or grain dealer or building supply co that has the side clearance to allow just one side reading at a time. CAT has a company policy to not do one side reading on their scales. That's why you see guard rail being placed close to the platforms at many truck stops.

The bottom line is you need enough readings to calculate the individual load on each tire to ensure no overloading of any tire. It is suggested that the heaviest loaded tire scale reading be no heavier than 85% of its theoretical max load.

Here is a chart on how to weigh and how to calculate.

RandyNH · 06-22-2018, 01:51 PM

Tireman9, what you suggest pertains to the trailer (correct?) side loading of the trailer tires and would not affect TV payload, GVWR or Axle or Tire ratings. Please explain that it is only for trailer tire specific ratings, so as not to confuse those asking the questions.

Bill M. · 06-22-2018, 03:45 PM

When calculating payload use the weight added to TV with the rig all hooked up. In the example above use the 840 lbs. the rest of the tongue weight is back on the trailer axles.

My 25’ seems rock solid. My 32’ seemed a little squirrel until I went to heavier bars on my Reese st line hitch. 7 feet of trailer and 2000 lbs seem to make a bit of difference in towing.

ITSNO60 · 06-22-2018, 06:37 PM

Mine is going to be a bit different...with all our stuff and two people in the cab my front axle weighs 5080 and is rated at 5200, so I will just be able to restore the weight back to the front axle after I hook up.

Tireman9 · 06-23-2018, 03:56 PM

Quote:

Originally Posted by RandyNH

Tireman9, what you suggest pertains to the trailer (correct?) side loading of the trailer tires and would not affect TV payload, GVWR or Axle or Tire ratings. Please explain that it is only for trailer tire specific ratings, so as not to confuse those asking the questions.

The worksheet I provided shows how to use the scale readings for a trailer for the Front axle, The rear axle and the load on the two right side (or Left side) tires and calculate the load on each of the 4 individual tires.

While it is possible to be under tha GAWR you can still overload a tire.

RF3850 LF 3150

LR 3750 RR 3200

Right side scale of two tires would be 7050# Left side would be 6900

So each axle has no more than the GAWR of 7,000#
BOTH the RF and LR exceed the tire max of 3500#

GVW of 14,000 would be OK in the above example.

Without getting ALL the above and doing the math the owner would assume all was OK till he started to have tire failures from overload on RF and LR tires.

The "Ratings" are the maximum that component is to be loaded. Rating is not the same as Scale reading.