2015 F250 Super duty, 6.7 lariat with towing package, and firestone 5000lbs air bags. Looking at a TH 38ft and 17,500 lbs. Is this too much load?

 

Probably is. Oh you can towing but you will be over on the tires probably.

Your rear axle right sits around 3100 lbs. Figure at least 20% of the trailer GVW for pin wt...or 3500 lbs at least.

Some toy haulers are really pin heavy.

Your gears in the F250 may be another issue. What gears you running?

 

Would you use a screwdriver to knock down a brick wall?
Would you use a candle to cook a steak? I don't know if you are looking at a truck to pull that camper or you are lookin at that camper to go on your truck, either way IMO,there is no worse felling than diving a rig down the road and feeling "under equipped" truck won't pull hills or trying to slow down or stop on the other side of that hill, or windy days, feeling like the camper is driving you, for me that's not fun. Then there is the feeling that you just spent a lot of money on this deal and your not happy. If you are buying the truck to fit the camper I would step up to a dually, if your buying the camper to fit the truck, I would step down the camper size to be more insid the limits of what the truck can handle.

 

You'll be way over on the numbers the factory states at 17,500 behind an F250. Pin weight will make all the difference here. If it's fairly low, you may be able to stay under on your rear axle and tires, but most TH's aren't light on the pin.


What is the make and model of the trailer?

 

IMO, that truck has ample drivetrain, frame, brakes, etc. It just ain't got the tires and probably not the springs...it's kind of an odd mismatch of power and weakness. Therefore, the truck doesn't have the payload rating which makes the scenario indefensible in legal eyes.

 

No rear sway bar on the truck = no way, that includes an F350 SRW (if you can order them without, IIRC rear stabilizer bar becomes standard on DRW unless you get a towing/ plowing package).

Stability isn't something you can look at the weight ratings to figure out, you have to think "is the sail on this thing so large that it'll rock the truck around". No way I'd pull a 5ver anywhere with hills without a VERY stable towing platform for the pin weight, which is a separate issue from just looking if you come in under the GAWR/tire load index.

 

I'm not trying to be contrary, it's just that you bring up a topic that I hadn't thought about for a while. Sway bars, (I believe) are for controlling body roll. I don't see how a sway bar on a truck will do anything to stabilize body roll of a 5th wheel...especially if you have a hitch platform that tilts side to side. Also, body roll only comes into play on curves...not up and down hills. I always thought the best way to control body roll of a tall fiver was to slow down on curves.

I believe duals and more springs will give more of the stability you're talking about than a sway bar.

 

Body roll on the truck is the concern, the 5th wheel hitch doesn't have any side to side roll on the vertical axis so sway over the kingpin is transmitted to the truck.

A sway bar is a component of stabilizing the truck, just like airbags, dual wheels and stronger springs; you can pick a different combination and not always upgrade all of them. Duallies are more stable in the mid-range of their capacity largely because of the springs and sway bar; if you ran the lowest rated springs from a SRW then the larger footprint for the tires wouldn't really do much because the contact point from spring to axle is the weakest link. The extra tires are for weight, and stability at the top end of the load range. If you have a the max rated springs pulling a gooseneck than a DRW isn't necessary if a SRW has sufficient GAWR to carry the load because vertical sway won't be as bad as if you were pulling a 5th wheel.

Higher rated springs are implicit in considering higher numerically badged trucks, but the way Ford builds theirs doesn't mean that a SRW F350 automatically comes with everything you need, nor is it automatically better than an F250 for towing a 5th wheel. Paper and legal ratings aside, mechanically speaking an F250 with the camper package that comes with rear aux spring and sway bar is better setup to tow a 5ver than a SRW F350 without the sway bar. The F350 DRW is built with a rear sway bar included, which means it has all three major components; wider wheel track, stiffer springs, rear sway bar.

I guess what I'm trying to get at is this, for towing a 5th wheel models stack up on packages moreso than badge:
Base F250
Base F350 SRW
F250 with packages to include upgraded rear springs and sway bar
F350 with packages to include usway bar
F350 DRW
F450 DRW
(paper ratings aside, assuming you're inside the envelope where ratings overlap. marginal loads and overloads you need to move to the minimum GWVR/GAWRs that are safe).

As for the hills comment, mainly it was a statement that hills tend to be round and include curves up and down. Nothing about a perfect front to back undulation would cause stability issues, it's just that rarely happens. Even in notoriously flat West Texas, Ranger hill is about a 1-mile 6% grade that runs along an s-curve that can be VERY dangerous to people who pull marginal loads, mainly overloaded minivans and SUVs with travel trailers, but occasionally a half-ton/5ver combo or something like an SRW/40' toy hauler can get seriously out of shape on that downhill. I lived in Denver for 14 years, so I plan every trip like it includes the Dillon-Eisenhower Tunnel pull from the Rumble in the Rockies shootout. I wouldn't pull a 38' toyahuler without a dually, but some people will be perfectly fine with a marginal setup like the OP talked about.