Tow vehicle suspension modifications necessary?

[7.3diesel]

TRUCK: 1997 F-250 Heavy Duty 7.3L Powerstroke 4x4.

There seems to be lots of detailed information about weight (dry v. loaded, what the truck's rated at, etc). According to Ford, provided I'm reading the document right, the GCWR for a 1997 4x4 manual 7.3L F-250 is 20,000lbs & 14,000 trailer weight. What is the maximum weight I can safely tow?

So I'm just now starting to investigate fifth wheels & I have a few novice questions that I'm hoping the community can help me with:

What modifications, if any, will improve ride quality & safety of my 1997 F-250 Heavy Duty 7.3L Powerstroke 4x4 when hauling a 5th wheel?
I'm currently looking into the TorkLift StableLoad, sway bars, add-a-springs, helper-spring kits, airbags & tires. I'm starting to get a bit overwhelmed and afraid of being sold something at the RV dealership that I can't safely tow... Does anyone have any recommendations on any of these mods?

Roughly at what trailer weight do people need to upgrade duallies?

Any experienced recommendations, suggestions & stories are much appreciated.

Thanks in advance!

[jhanan]

You can tow GVWG - Curb Weight = how much you can tow off the back. But for 5th wheel, you need to think about how much you can weight on the truck you can take - must be less than 3/4 ton - but 5th wheel hitch ratings are normally less than that. Find your year tow guide on ford.com. The max 5th wheel for an F250 is about 15000 lbs. You need to look it up or call your local ford dealer. Don't over load it, as none of the add-ons will really help in that case. Air bags will give better ride, and level out the vehicle.

[7.3diesel]

Originally Posted by jhanan

You can tow GVWG - Curb Weight = how much you can tow off the back. But for 5th wheel, you need to think about how much you can weight on the truck you can take - must be less than 3/4 ton - but 5th wheel hitch ratings are normally less than that. Find your year tow guide on ford.com. The max 5th wheel for an F250 is about 15000 lbs. You need to look it up or call your local ford dealer. Don't over load it, as none of the add-ons will really help in that case. Air bags will give better ride, and level out the vehicle.

Thanks for the advice. I should have been more specific. I'm not asking about modifications to increase my towing capacity. I'm asking about mods for increased towing safety & people's experiences with the different mods & what they recommend.

[7.3diesel]

Front FAWR 4600 lb
Rear GAWR 6084 lb
GVWR 8800lb

[7.3diesel]

So I went 5th wheel shopping yesterday & looking at the sticker on the 5th wheel I noticed that the trailers had their own GVWR ranging from 7,000 to 16,000 lbs.
What does this rating mean?
Is this the 5th wheel's so called "dry weight"? If not, where do I find the dry weight?
According to a lot of salespeople I talked to yesterday, "a 3/4 ton truck can pull anything but a fully loaded toy hauler". I don't trust them.
What numbers on the trailer to I need to be looking at?

[7.3diesel]

I think I figured it out!

Data stickers

&

Understanding ratings

So, as I understand these explanations, the trailer's GVWR is not the same as the trailer's UVW.
The trailer's GVWR is the maximum weight the trailer's axles can handle: weight of the trailer + weight of (potentially) a lot of cargo is the maximum weight the trailer can safely have on its own axles.
The more important numbers to look at on the trailer, in order to know if the truck can tow it, is the Unloaded Vehicle Weight (UVW) & the Cargo Carrying Capacity (CCC). We need to add the the UVW + what we think our CCC's going to be to know if we can to it or not. GVWR means nothing for towing.
Example:
UVW of trailer: 7,000 lbs
CCC of trailer: 2,000 lbs
GVWR of trailer: 14,000 lbs
GVWR of truck: 10,000 lbs according to people I trust & 13,800 according to manufacturer
Since UVW + CCC = 9,000 lbs we are under 10,000 lbs. Conclusion: we can safely tow it!
In this case, if the CCC is 3,001 lbs + UVW = 10,001 probably unsafe for my truck to tow.
In this case, if the CCC is 7,001 lbs + UVW = 14,001 probably unsafe for the trailer to carry this much cargo.

This calculation does not take into account GAWR (Gross Axle Weight Rating) of truck. Which is just as important to calculate. The truck's Front Axle Weight Rating (FAWR) is 4,600 lb & it's Rear Axle Weight Rating (GAWR) is 6,084 lb.
The trailer will have 20-25% of its weight on the truck's axles (front & rear, but mostly rear).
In this case if our UVW + CCC = 9,000 lbs the Hitch Pin / Tongue Weight (the weight the truck's axles can hold with a fully loaded trailer pushing down on the 5th wheel hitch) is 1,800-2,250 lbs. The truck's axles can easily take it!

[Bamaman]

Your 1997 model truck is approach 18 model years old, and there's been substantial changes over the years in 3/4 ton and 1 ton trucks. While I'm sure you have a tough old truck, Ford made substantial 7.3 engine modifications with the introduction of the SuperDuty trucks in 1999.

Your truck really just doesn't have the horsepower to tow 14K lbs. dry weight that many popular fifth wheels have. Even the late model 3/4 ton trucks are bastard units in that they don't have the Pin weight capabilities (often 3K+) that a full size fifth wheel trailer has.

You could spend a quick $2-3K on your truck to make it more roadworthy, but you'll still be left with an old generation truck. You'd probably do best to clean your truck up and retail it yourself. Then, go find a later model truck that's worth spending some money on.

I recently equipped my 2003 F250 7.3 diesel for towing. I put a D-P Tuner on it ($300), set of 3 gauges ($303), AirRide air bags ($195), a TruCool transmission cooler ($150), a B&W Patriot hitch ($300), a set of rails and custom hitch mount ($195) and a Curt in bed wiring harness ($65.)

One important issue is the basic condition of the truck. Any tow truck should have suspension components and brakes @ 100% condition. I'm changing my Hawk LTS brake pads over to Wagners. I have fresh shocks, and alignment.

Getting ready for towing gets downright expensive. But I've done about all I can for the price spent.

A last issue is towing with 4x4 3/4 ton or 1 ton trucks. If they're lifted and have big tires, they can be too tall to tow a 5th wheel trailer.

[7.3diesel]

Originally Posted by Bamaman

Your 1997 model truck is approach 18 model years old, and there's been substantial changes over the years in 3/4 ton and 1 ton trucks. While I'm sure you have a tough old truck, Ford made substantial 7.3 engine modifications with the introduction of the SuperDuty trucks in 1999.
Your truck really just doesn't have the horsepower to tow 14K lbs. dry weight that many popular fifth wheels have. Even the late model 3/4 ton trucks are bastard units in that they don't have the Pin weight capabilities (often 3K+) that a full size fifth wheel trailer has.
You could spend a quick $2-3K on your truck to make it more roadworthy, but you'll still be left with an old generation truck. You'd probably do best to clean your truck up and retail it yourself. Then, go find a later model truck that's worth spending some money on.
I recently equipped my 2003 F250 7.3 diesel for towing. I put a D-P Tuner on it ($300), set of 3 gauges ($303), AirRide air bags ($195), a TruCool transmission cooler ($150), a B&W Patriot hitch ($300), a set of rails and custom hitch mount ($195) and a Curt in bed wiring harness ($65.)
One important issue is the basic condition of the truck. Any tow truck should have suspension components and brakes @ 100% condition. I'm changing my Hawk LTS brake pads over to Wagners. I have fresh shocks, and alignment.
Getting ready for towing gets downright expensive. But I've done about all I can for the price spent.
A last issue is towing with 4x4 3/4 ton or 1 ton trucks. If they're lifted and have big tires, they can be too tall to tow a 5th wheel trailer.

Thanks for all the great advice Bamaman.
I've got a tuner already with tow settings. I've got boost & EGT gauges. I've also got an aftermarket intake & aftermarket turbo-back exhaust. Mine's a manual, so I don't think I need a transmission cooler.
What shocks do your recommend? I heard the Rancho 9000s are good for towing.
What tires do you recommend for towing?
Thanks again.

[Gordon Dewald]

Originally Posted by 7.3diesel

I think I figured it out!

&

So, as I understand these explanations, the trailer's GVWR is not the same as the trailer's UVW.
The trailer's GVWR is the maximum weight the trailer's axles can handle: weight of the trailer + weight of (potentially) a lot of cargo is the maximum weight the trailer can safely have on its own axles.
The more important numbers to look at on the trailer, in order to know if the truck can tow it, is the Unloaded Vehicle Weight (UVW) & the Cargo Carrying Capacity (CCC). We need to add the the UVW + what we think our CCC's going to be to know if we can to it or not. GVWR means nothing for towing.
Example:
UVW of trailer: 7,000 lbs
CCC of trailer: 2,000 lbs
GVWR of trailer: 14,000 lbs
GVWR of truck: 10,000 lbs according to people I trust & 13,800 according to manufacturer
Since UVW + CCC = 9,000 lbs we are under 10,000 lbs. Conclusion: we can safely tow it!
In this case, if the CCC is 3,001 lbs + UVW = 10,001 probably unsafe for my truck to tow.
In this case, if the CCC is 7,001 lbs + UVW = 14,001 probably unsafe for the trailer to carry this much cargo.

This calculation does not take into account GAWR (Gross Axle Weight Rating) of truck. Which is just as important to calculate. The truck's Front Axle Weight Rating (FAWR) is 4,600 lb & it's Rear Axle Weight Rating (GAWR) is 6,084 lb.
The trailer will have 20-25% of its weight on the truck's axles (front & rear, but mostly rear).
In this case if our UVW + CCC = 9,000 lbs the Hitch Pin / Tongue Weight (the weight the truck's axles can hold with a fully loaded trailer pushing down on the 5th wheel hitch) is 1,800-2,250 lbs. The truck's axles can easily take it!

You are getting close to the calculations.

For simplicities sake take the GVWR of the trailer and multiply it by 20 - 25% (14000 x .25 = 3500). Use that as the pin weight. Add that weight plus 150 lbs for the 5 wheel to the loaded axle weight (rear) of the truck.

The loaded axle weight of the truck is with you, DW, full fuel, propane tank(? if you carry an extra), grill, lunch, pups and anything else you have will have in the back of the truck when you are pulling the trailer.

If the sum of the pin (3500) + hitch (150) + axle weight (???) is more than 6084 you will be overloaded.

If you add the loaded weight of the truck (???) and the pin (3500) + hitch (150) and you are overloaded if you are heavier than 8800 (previous post but seems light - you may want to check the numbers on the sticker on the door pillar)

Obviously the absolute best way to do it is to weigh the loaded trailer and the loaded truck with the trailer hooked up and unhooked. These will give you hard numbers.

I find CCC to be difficult to fathom. It will depend upon the manufacturer as to how they define it. CCC = GVWR - (UVW + water + propane + ????). I think of it as the GVWR minus the working weight of the trailer. I do not think manufacturers are consistent in what they add. I find it easier to use the GVWR for the trailer for calculation purposes.

Placement of the 5 wheel will make a difference as well. If the hitch is in front of the axle the weight on the front will be slightly increased and on the rear reduced by a slight amount. If the hitch is behind the axle the weight on the front axle will be reduced and the back increased.

Air bags will make the truck ride level but do not change the RGAWR rating of the truck.

Good luck with your acquisition and setup.

Wave as you pass by. We will recognize you by the big grins.

[SmokeyWren]

Originally Posted by 7.3diesel

Front FAWR 4600 lb
Rear GAWR 6084 lb
GVWR 8800lb

Your limiter will be the GVWR.

With my '99.5 7.3L CrewCab 4x2 dragging my 25' 5er that grossed 8,000 pounds, I was usually overloaded by a few hundred pounds over the GVWR of the F-250. My "tow rating" was over 13,000 pounds, but that is a myth that assumes no options on the truck and absolutely nothing in the truck but a skinny driver. I had Rhino bed liner, aluminum tool chest full of tools and extra fluids, just Darling Wife and Puppydog in the cab. But I was overloaded with an 8,000-pound 25' 5er

Your PowerStroke is close to mine in power and torque, except you don't have the charge air cooler (intercooler) of the SuperDuty. With a DP-Tuner 60-tow or 80-tow tune, along with aftermarket intake and exhaust system, you'll have plenty of power for all but the really-steep mountain passes. Drive by the pyrometer, and NEVER exceed 1,250° EGT when climbing the mountain and your 7.3L will continue to live a long life.

You drive a stick, so I'm sure you understand that you should NEVER allow the engine to lug. Downshift so you will have at least some go pedal left when climbing long steep grades.

What is the maximum weight I can safely tow?

If you define "safely" as not exceeding any of Ford's weight ratings, then probably no more than about 8,000 pounds fifth wheel or 9,000 pounds TT.

Hitch weight is your limiter, and my 8,000-pound 5er had about 16% hitch weight, or 1,280 pounds. TTs have less hitch weight averaging about 12.5%, so a 9,000 pound TT with 12.5% hitch weight would have 1,125 pounds hitch weight.

Your OBS truck weighs less than my SuperDuty, but your 4x4 adds about 400 pounds to your truck weight. So I'll bet your limit of 8,000 pounds 5er or 9,000 pounds TT is close to accurate.

One way to know for sure is to load the F-250 with everything that will be in it when towing: people, tools, jacks, pets, everything, including the 5er hitch or the shank and head from your weight-distributing TT hitch. If you don't have the hitch yet, estimate 150 pounds for the 5er hitch and 75 pounds for the TT hitch. Subtract the weight of your wet and loaded F-250 from the 8,800 pounds GVWR of the F-250 and the answer is the max hitch weight you can have without being overloaded. If your max hitch weight is less than about 1,300 pounds, then you should forget about a 5er and look for a TT.

Ignore those that claim a 5er tows better than a TT. That's true only if your TT hitch (including shank) is an el cheapo hitch that costs less than about $500 from Amazon or ETrailer. My Reese Strait-Line dual cam hitch on my cargo trailer tows as good as any 5er. My ProPride hitch on my TT tows better than any 5er.

Ignore all that nonsense about UVW and CCC and use the GVWR of the trailer. Old experienced RVers will confirm that you'll probably have the trailer loaded to near the GVWR soon after you begin RVing.

Tires for the F-250. Your stock size was LT235/85R16E. Stick with that size. Your best bet is Michelin XPS Rib tires - expensive but cost effective in the long run. If you have to have more traction because of snow or mud, then put XPS Traction tires on the rear and Ribs on the front. Only if you have to put up with really nasty road conditions would you want XPS Traction front and rear.

Michelin XPS Rib

Michelin XPS Traction

[7.3diesel]

Originally Posted by SmokeyWren

Your limiter will be the GVWR.
With my '99.5 7.3L CrewCab 4x2 dragging my 25' 5er that grossed 8,000 pounds, I was usually overloaded by a few hundred pounds over the GVWR of the F-250. My "tow rating" was over 13,000 pounds, but that is a myth that assumes no options on the truck and absolutely nothing in the truck but a skinny driver. I had Rhino bed liner, aluminum tool chest full of tools and extra fluids, just Darling Wife and Puppydog in the cab. But I was overloaded with an 8,000-pound 25' 5er

What does Rhino bed liner weigh, roughly?

Originally Posted by SmokeyWren

Your PowerStroke is close to mine in power and torque, except you don't have the charge air cooler (intercooler) of the SuperDuty. With a DP-Tuner 60-tow or 80-tow tune, along with aftermarket intake and exhaust system, you'll have plenty of power for all but the really-steep mountain passes. Drive by the pyrometer, and NEVER exceed 1,250° EGT when climbing the mountain and your 7.3L will continue to live a long life.

My pyrometer just arrived in the mail

Originally Posted by SmokeyWren

If you define "safely" as not exceeding any of Ford's weight ratings, then probably no more than about 8,000 pounds fifth wheel or 9,000 pounds TT.

Dry or wet weight?

Originally Posted by SmokeyWren

Hitch weight is your limiter, and my 8,000-pound 5er had about 16% hitch weight, or 1,280 pounds. TTs have less hitch weight averaging about 12.5%, so a 9,000 pound TT with 12.5% hitch weight would have 1,125 pounds hitch weight.
Your OBS truck weighs less than my SuperDuty, but your 4x4 adds about 400 pounds to your truck weight. So I'll bet your limit of 8,000 pounds 5er or 9,000 pounds TT is close to accurate.
One way to know for sure is to load the F-250 with everything that will be in it when towing: people, tools, jacks, pets, everything, including the 5er hitch or the shank and head from your weight-distributing TT hitch. If you don't have the hitch yet, estimate 150 pounds for the 5er hitch and 75 pounds for the TT hitch.

A quick internet search comes up with 6,200 lbs dry weight for my truck. Roughly, what do you think this would come out to weigh wet?
I've got plans to weigh my loaded wet truck, just haven't got 'round to it yet.

Originally Posted by SmokeyWren

Subtract the weight of your wet and loaded F-250 from the 8,800 pounds GVWR of the F-250 and the answer is the max hitch weight you can have without being overloaded. If your max hitch weight is less than about 1,300 pounds, then you should forget about a 5er and look for a TT. Ignore those that claim a 5er tows better than a TT...

Firstly, there's absolutely no way I'm going to be considering anything other than a 5th wheel for multiple reasons, but one of the main ones being that I'll be full-timing in it.
Second, I was under the impression that the steps are as follows: weigh the full weight of the wet truck, calculate how much wet truck weight is on the axles (especially the rear), weigh the fully loaded wet trailer hitch-fuel-& all, calculate how much weight the trailer will be putting on the hitch, taking into account the GAWR & tire ratings figure 20-25% of the full weight of the wet trailer will be on the tongue over the rear axle.
As I see it, there are 3 possible weakest links in this chain: the truck's GVWR, the rear axle's GAWR, or the tires.

Originally Posted by SmokeyWren

Ignore all that nonsense about UVW and CCC and use the GVWR of the trailer. Old experienced RVers will confirm that you'll probably have the trailer loaded to near the GVWR soon after you begin RVing.

With all due respect, figuring the CCC is very important for a full-timer, IMO.

Originally Posted by SmokeyWren

Tires for the F-250. Your stock size was LT235/85R16E. Stick with that size. Your best bet is Michelin XPS Rib tires - expensive but cost effective in the long run. If you have to have more traction because of snow or mud, then put XPS Traction tires on the rear and Ribs on the front. Only if you have to put up with really nasty road conditions would you want XPS Traction front and rear.

Michelin XPS Rib

Michelin XPS Traction

Thanks a bunch for the tire recommendations; that's very helpful.

[SmokeyWren]

Originally Posted by 7.3diesel

What does Rhino bed liner weigh, roughly?

About 100 to 150 pounds, depending on how thick the installer sprays it on.

Dry or wet weight?

GVWR, or wet and fully loaded weight. Never use dry weight for anything. Nobody tows an empty dry RV trailer

A quick internet search comes up with 6,200 lbs dry weight for my truck. Roughly, what do you think this would come out to weigh wet? .

My 7.3L PowerStroke CrewCab 4x2 longbed had a wet and loaded weight of about 8,000 pounds before tying onto the 5er. Yours probably will weigh about that much too, especially since a full-timer has to haul everything he owns when moving the trailer.

I've got plans to weigh my loaded wet truck, just haven't got 'round to it yet

The CAT scale is your friend. Use them. Often.

Firstly, there's absolutely no way I'm going to be considering anything other than a 5th wheel for multiple reasons, but one of the main ones being that I'll be full-timing in it.

Somewhere you have been misled. There is nothing that says you need a 5er for full timing. Lots of full-timers live with a TT. If you have "enuff truck" to haul a 5er, good. But your truck is probably not enuff truck to haul much of a 5er without being overloaded.

Second, I was under the impression that the steps are as follows: weigh the full weight of the wet truck, calculate how much wet truck weight is on the axles (especially the rear), weigh the fully loaded wet trailer hitch-fuel-& all, calculate how much weight the trailer will be putting on the hitch, taking into account the GAWR & tire ratings figure 20-25% of the full weight of the wet trailer will be on the tongue over the rear axle.
As I see it, there are 3 possible weakest links in this chain: the truck's GVWR, the rear axle's GAWR, or the tires.

A lot of useless figuring. Your limiter is the GVWR of the pickup. If you don't exceed the GVWR of the pickup, then you won't exceed any of the other weight limits.

With all due respect, figuring the CCC is very important for a full-timer, IMO.

The CCC is not important in matching trailer to tow vehicle. All you need is actual wet and loaded hitch weight, and hitch weight is a percentage of GVWR. So the only trailer spec you need is the GVWR of the trailer. For any 5er you can tow without exceeding the GVWR of your tow vehicle, hitch weight will probably be about 17% of the GVWR of the trailer.

Yeah, heavier and fancier 5ers have 20% to 25% hitch weight, but you cannot tow one of those without being overloaded. The heaviest 5er you can tow without being overloaded probably has GVWR of around 8,000 pounds with about 17% pin weight.

Thanks a bunch for the tire recommendations; that's very helpful.

Based on wearing out several sets of tires on my F-250 PSD. OEM General Grabber lasted about 25,000 miles. WalMart elCheapo tires lasted about 20,000 miles. BFGoodrich AllTerrain LT295/75R16E lasted about 25,000 miles. Cooper Discoverer LT285/75R16E lasted about 25,000 miles. Michelin XPS Traction LT235/85R16E lasted about 40,000 miles on the rear axle. Michelin XPS Rib LT235/85R16E lasted about 45,000 miles on the front axle on one set and on both axles on another set. When I sold the truck I was on the second set of Ribs all around.

[caissiel]

Your truck a great towing unit. Just don't overload the rear tires. The brakes might be better than my 2005 rear discs that need to much attention compared to my previous 98 GM.
Your spring capacity should carry better then most. But they are old and check them out.
I take that you know your truck and value it.
Much better the an other truck you will need to learn again the limitation and condition.
I know a 72 owner that is the show at every stop and the envy of many. He travels everywhere with great fun.

[Kiwi]

Reading this thread gives me a headache.