CAT Scale Weights Unloaded - Am I Safe?

[Scratch]

Stopped by the CAT scale this morning with DW in the passenger seat and weighed the truck/5er . Truck had about 1/3 tank of fuel and the trailer was empty.

This morning's CAT numbers reflect:

Steer Axle: 4,960
Drive Axle: 5,460
Trailer Axle: 8,500
Gross Weight: 18,920

The truck is a 2012 F250 with the following factory specs per the door sticker:

Front GAWR: 5,600
Rear GAWR: 6,100
GCWR: 23,500

GVWR: 10,000

The truck has 3.55 gears however, the dealership upgraded the tires wheels from 18s to 20 inch rims which (as I understand) makes the ratio more like 3.31.

As I read the numbers, I'm within specs except that that when I add the front and rear GAWR, I get 10,420, which puts us over GVWR by 420 lbs.

When I pointed this out to the folks at the RV dealership, they said I'm over-analyzing and should not be concerned as the truck is more than capable.

We took our maiden voyage to the coast this past week with about 800lbs added to the (empty) weights above. Other than some chucking, it seemed to drive OK.

Just want to make sure of our safety as we plan lots more travel this year.
Thoughts/advice greatly appreciated.

[rnkburg]

Looks like you are under if you weigh 18k and your truck is rated for 23k gross combined

Sent from my EVO using Tapatalk 2

[mhs4771]

Don't know what you want us to tell you. You already knew you were 400 Lbs over GVWR, than add another 800 Lbs, now making you 1200 Lbs over. Your setup, your call.

[Festus2]

Scratch -
As was just pointed out in the previous post, you are about 1200 lbs over if you take into account the data from the scale (400 lbs) and the additional weight (800 lbs) you factored in.
It seems as if you have answered your own question..."Am I safe?".

Some chucking will occur even if you are well below your limit but could be reduced by the addition of a different pin box such as Trail Air or some other. However, the chucking really doesn't enter the equation and is not the main issue here. IMO.

Saying that it "felt okay" could give one a false sense of security without fully realizing what kind of unsafe predicament in which you could find yourself. As you said, "I just want to make sure of our safety".

[hankpage]

First of all the dealer did not do you any favors by increasing tire size. Your rear end ratio was too high to begin with. (Higher numbers mean lower ratio) 3:73 is a good compromise for towing and solo economy, 4:10 or lower ( higher #like 4:50) is ideal for towing. With the final ratio that you have your truck will hate hills and head winds with a loaded trailer. Dealers want to SELL TRAILERS, they don't care about you. Try to travel safely, Hank

[Scratch]

I really appreciate your replies, and yes; I know I'm over. Maybe I'm just looking for others to chime in and say "Hey I've towed a rig like that for 30 years with no problem!" I see those all the time on a variety of forums. I know that sounds ridiculous...

Got a lot of money tied up in this rig and here I sit contemplating yesterday's decisions.

Guess my next question is: How many others tow with similar setups?

[f6bits]

Changing wheel size doesn't mean much unless the overall tire diameter changed. You can use this to find out:
http://www.miata.net/garage/tirecalc.html

And then check the load rating on your tires to make sure they add up to at least your rear GAWR.

[Scratch]

Originally Posted by f6bits

Changing wheel size doesn't mean much unless the overall tire diameter changed. You can use this to find out:
http://www.miata.net/garage/tirecalc.html

And then check the load rating on your tires to make sure they add up to at least your rear GAWR.

Good point. Just checked the tires which are Michelin LT275/65R20 with a load range of 123 (3417 lbs per tire). I'm assuming this means 3417 X 2 = 6834 lbs shared across the rear axle... Per the door sticker, the rear axle is rated at 6100 lbs. Seems the tires then, are OK?

[JRTJH]

Originally Posted by Scratch

Good point. Just checked the tires which are Michelin LT275/65R20 with a load range of 123 (3417 lbs per tire). I'm assuming this means 3417 X 2 = 6834 lbs shared across the rear axle... Per the door sticker, the rear axle is rated at 6100 lbs. Seems the tires then, are OK?

Wheel size, as stated above doesn't matter if the overall tire diameter remains the same. Example: I have LT275 65R18's on my truck. The optional wheel/tire combination is LT275 55R20. The overall diameter of both is within 2/10" (32.1 vs 31.9) and the revolutions per mile is 648 : 652. So essentially, as far as the gearing ratio of the truck, it is effectively the same with either the 18's or the 20's installed. The difference is accommodated for in the sidewall height. It's 65% of the tread width on the 18's and 55% on the 20's.

Hope that helps a little. The reason I went with 18's is that it's easier to find replacement tires at a reasonable price for 18" wheels, and a bit tougher to find them for the 20" ones. Of course that has changed somewhat in the past 3 years from when I bought my truck.

[Scratch]

Originally Posted by JRTJH

Wheel size, as stated above doesn't matter if the overall tire diameter remains the same. Example: I have LT275 65R18's on my truck. The optional wheel/tire combination is LT275 55R20. The overall diameter of both is within 2/10" (32.1 vs 31.9) and the revolutions per mile is 648 : 652. So essentially, as far as the gearing ratio of the truck, it is effectively the same with either the 18's or the 20's installed. The difference is accommodated for in the sidewall height. It's 65% of the tread width on the 18's and 55% on the 20's.

Hope that helps a little. The reason I went with 18's is that it's easier to find replacement tires at a reasonable price for 18" wheels, and a bit tougher to find them for the 20" ones. Of course that has changed somewhat in the past 3 years from when I bought my truck.

Makes even more sense as Ford's GCWR for the 3.31 and the 3.55 are the same at 23,500. We're well within specs on GCWR... The tires appear within specs.

Doesn't help the GVWR; however where it appears we'll be over the 10K Ford GVWR spec by about 1,200 lbs if we add 800 lbs of payload to the 420 lbs already in excess as dry weight. Tough to think we're driving safely at 1200 over the recommended GVWR...

[hankaye]

Scratch, Howdy;

Go back to the Cat scale, without the trailer. Have the rest of the set-up the same... see what the weight is. If you are under the GVW then what's the problem?

The sticker weights say according to your first post;
"Front GAWR: 5,600
Rear GAWR: 6,100
GCWR: 23,500"

Front + Rear = 11,700... Where's the problem ...?

hankaye

[f6bits]

GVWR is 10,000.
.
.
.
Wait for it…

Originally Posted by hankaye

Front + Rear = 11,700... Where's the problem ...?
hankaye

[Festus2]

Originally Posted by Scratch

Doesn't help the GVWR; however where it appears we'll be over the 10K Ford GVWR spec by about 1,200 lbs if we add 800 lbs of payload to the 420 lbs already in excess as dry weight. Tough to think we're driving safely at 1200 over the recommended GVWR...

A few more questions to consider......

1) When you weighed in at the scales, would having a full tank of gas instead of 1/3 tank changed the numbers? If so, would the increased weight of the fuel work in your favour and reduce the 1200 lbs or make your situation worse by adding to it?

2) When you packed your 5th wheel, did you pack very conservatively or would you normally take more stuff than you did on your first trip? Off the top, 800 pounds sounds quite conservative to me. I would be thinking that 1000 lbs would be more like it but I realize that the amount of stuff people take varies considerably.

3) There is currently a thread about how much water people take with them in their FW tank. If you put water in your FW tank, did you include that weight in the 800 lbs??

[Scratch]

OK; more confused than ever here...

The Cougar's dry weight is 10,160.

This morning's empty CAT trailer axle weight is 8,500

That tells me 1,660 lbs have been transferred to the truck; thus 1,660 lbs tongue weight.

Combined truck steer/drive axle weight is 10,420.

Ford GVWR is 10,000 lbs, thus I am over GVWR by 420 lbs.

If my GVWR is 10,420 and I carry an additional 800 lbs of payload, I'm then 1220 lbs over my desired/max GVWR.

Is my desired 5er weight to achieve 10,000 GVWR around 8,000 lbs?

[Ken / Claudia]

Check the ford spec. sheet or ask the dealer what is difference beween 250/ 350, for years it was tires and springs regarding GVWR. Get a 350 or aftermarket spring kit and up the load rating if you feel the need for more weight carrying cap.

[warsw]

Originally Posted by Scratch

OK; more confused than ever here...

The Cougar's dry weight is 10,160.

This morning's empty CAT trailer axle weight is 8,500

That tells me 1,660 lbs have been transferred to the truck; thus 1,660 lbs tongue weight.

Combined truck steer/drive axle weight is 10,420.

Ford GVWR is 10,000 lbs, thus I am over GVWR by 420 lbs.

If my GVWR is 10,420 and I carry an additional 800 lbs of payload, I'm then 1220 lbs over my desired/max GVWR.

Is my desired 5er weight to achieve 10,000 GVWR around 8,000 lbs?

Did that 800# go in the trailer or on the truck? If it went in the trailer then it wouldn't be adding 800# to the truck. In fact, dependind on how it was loaded in the trailer, it may have reduced the amount of weight on the truck. Just a thought.

[Javi]

Originally Posted by hankpage

First of all the dealer did not do you any favors by increasing tire size. Your rear end ratio was too high to begin with. (Higher numbers mean lower ratio) 3:73 is a good compromise for towing and solo economy, 4:10 or lower ( higher #like 4:50) is ideal for towing. With the final ratio that you have your truck will hate hills and head winds with a loaded trailer. Dealers want to SELL TRAILERS, they don't care about you. Try to travel safely, Hank

Hank, his truck has a diesel motor.... 3:31's or 3:55's are just fine although you couldn't give me 20" wheels...

[Jim W]

OK I know I will catch ____ from the weight police but here is my take on the 5er and tow vehicle weights. First some background on how I arrived at my opinion.

Now this is based on 40 years of experience from designing tractors at Caterpillar and my understanding of the vehicle weights and how they are applied. Also I am basing this too on the Ram Body Builders Guide were they publish towing weights and load rating on their vehicles. I am sure that the Ford trucks are very similar to the Ram vehicles in towing ability.

GVWR= is the most a vehicle can weigh with a payload in the bed and fully load with passenger /driver and fuel with accessories. Ram trucks stated that the GVWR is 9,000 LBS; this is 1,590 LBS pay load and a base weight of 7, 408 LBS for a 2008 MEGA Cab 4X4.

GCVW= is what the truck and tow vehicle combined weights can be. Ram states this is 20,000 LBS so the truck weight and trailer weight combined cannot exceed 20,000 LBS.

GAWR= the maximum amount of weights that can be applied to the axles. The front is 5200 LBS and the rear is 6010 LBS.

Maximum trailer weight for a 2008, 2500HD diesel from Ram is 12,450 LBS

Now I have weighed my combination of trailer and truck on a CAT scale. My conditions when weighed were fully loaded trailer for two week camping trip, wife myself, full load of diesel and all the other accessories in the truck such as tools and extra filters.

My weights were: Front Axle 4,940 LBS, Rear Axle was 5,160 LBS, Trailer Axles 8,140 LBS. and the GCVW of 18,240 LBS. So I am will within the specs for the RAM 6.7L 3:73 Mega Cab truck to tow this trailer. I do not consider payload or GVWR when towing a trailer. Ram does not consider the requirements that GVWR and Pay load are needed for the Maximum towing capability of their vehicles. Their formal for the maximum trailer weight is: GCVW- Base weight of truck- 150 lbs weight allowance for the driver. This is the 90% man which SAE figures as operator weight.

So after this long post to me you are within the ball park since you did not exceed the GAWR, GCVW of your truck.

Just my opinion.
Jim W.

[hankpage]

Originally Posted by Javi

Hank, his truck has a diesel motor.... 3:31's or 3:55's are just fine although you couldn't give me 20" wheels...

The longer the grade or the stronger the head wind and getting up to speed, the the difference in ratios is VERY noticeable. The engine and trans will be working much harder with 3:31 gears. JM2¢, Hank

[Javi]

Originally Posted by hankpage

The longer the grade or the stronger the head wind and getting up to speed, the the difference in ratios is VERY noticeable. The engine and trans will be working much harder with 3:31 gears. JM2¢, Hank

Before I owned this truck I would have agreed with you... but after driving the F-250 with 3:31 gears and the 6.7 I no longer think the combo might be under geared.. although I will admit I do have 17" wheels & tires 32 1/2" I wouldn't want more than 3:55's unless I was pulling 20K up Wolf Creek on a daily basis... The gear ratio of this 6 speed is just a perfect match for the power band of the 6.7...