Help me understand suspension and tires benfits on F350 w 2000lbs truck camper

[GetOutThere!]

I have a 2023 F350 4x4 8 foot bed with a 2000lbs Scout Camper. Truck has stock tires- Bridgestone A/T Duelers. My stock tires are 275/70r18 125/122r

I would say bone stock it handles the camper well- the camper eats maybe half my payload. No swaying or anything like that- I can hardly tell its back there.

Truck spends much of its time on decent forest roads in Central Oregon. It's basically exclusively a camping rig- not a daily driver. Camper stays on. I generally air down from 80 PSI to 55 PSI when on the forest roads for any length of time.

Biggest issue I have encountered is washboard roads. Clearance is rarely an issue. I don't tackle anything too crazy currently- I just don't have the experience and have found lots of nice spots that don't require it.


Would suspension modification help a bunch with this? Tires? What set-up would be recommended?

 

[Sparse Gray Hackle]

IMO… Your truck is fine as is. Depending on which model F350 you own, you probably have close to 4400 pounds of payload. If you don't have a sway bar, and sway is an issue, you might add one. Same for airbags if you need to level.

I am not a fan of Bridgestone tires, but that’s not a big deal.

 

[BajaSurfRig]

I’d say tire to wheel size ratio is one of the more important things to get sorted for washboard roads (as well as airing down). Ideally you want the tire diameter to be twice the wheel diameter (if you can accomplish more that will equate to a better ride). If you have 18” wheels I’d say a good tire size for stock suspension is 285/75r18. Great load carrying capacity and is a skinny 35”. This is the size I will be going with once my current tires need to be replaced.

 

[tacollie]

I would also get your truck weighed and download a load inflation table for your tires. Our F250 weighs 9600 LBS fully loaded. We have 285/75r18. I run 50psi front and 56 psi rear on road. For washboard I drop 8-10 psi. For trails 25-35 psi depending on the terrain.

 

[GetOutThere!]

My stock tires are 275/70r18 125/122r for what its worth.

Will update OP.

Is there a big difference between those and the 285/70r18 mentioned?

 

[rruff]

Is there a big difference between those and the 285/70r18 mentioned?

285/75r18... not 70. Nominally it's 34.8" diameter vs 33.2" diameter for the 275/70r18.

I think that is a fine choice if you are ready to get new tires, but I would look at the obvious free option first. Tire pressure.

You're tires are supposed to carry 3640 lbs at 80 psi. I doubt you are anywhere near that.

Lets say you are at 9,000 lbs loaded for a trip, with even for-aft balance, so 2,250 lbs per tire. Per this chart:

StackPath

... a LT 275/70r18 will support 2250 lbs with 40 psi. So on the highway, you have been running 2x the pressure you need, and you'd probably be fine dropping down to 30 psi on washboard or even less.

 

[GetOutThere!]

Can I get my truck weiged when loaded at any ODOT weigh station or is that just for tractor trailers?

Just pull up and ask? Do they give you the weight at each wheel?

 

[GetOutThere!]

Ahh- looks like CAT scales is the way to go?

Checked my pressures again- I am actually running 50 upfront and 70 rear when loaded. Not 80 as I mentioned- not sure how I had that wrong.

 

[AbleGuy]

You might be able to pay for a weight check at a commercial truck stop, or even the county landfill in some places.

 

[klahanie]

My stock tires are 275/70r18 125/122r for what its worth.

Will update OP.

Is there a big difference between those and the 285/70r18 mentioned?

Pressure wise, it's about 10%. So if you are heavy and with a stiff suspension running say 70psi and can drop that down to ~63psi thanks to the higher load rating of the larger tire, then I'd say yes it can make a difference for off highway driving.

Naturally going from 30 to 27 psi would be less noticeable.

Note that those inflation tables are a standard that a tire mfr can meet. The charts states the maximum load for a given psi to meet the standard. Nothing saying you can't use a higher psi (to max on the side wall).

And nothing saying you can't go lower (one guy even made his own low psi chart) but some caution is prudent, particularly rate of travel. If you're going to run low, low psi keep a check on tire temps.

Often you'll read folks concerned about unseating a tire at low pressure but driving characteristics can also change - notably steering. If you're dodging loaded log trucks, esp at speed, you'll want responsive steering.

As for ...

Biggest issue I have encountered is washboard roads.

what exactly is the issue ? bottoming out, jarring ride, loss of control, something else ?

 

[GetOutThere!]

Jarring ride. Doesnt feel great for rig. I know I can speed up but often not a wise option

 

[tacollie]

Tires are the cheapest option. F250/350 don't have a ton of wheel travel. An upgraded shock such as a Fox 2.0 will help. I opted for Carli coils which are a huge improvement but they are more money and level/lift the front end.

The other issue is you probably aren't heavy enough to engage the top overload spring in the rear. That causes a harsher ride. There are options to address it but it really depends on how you use your truck and how much of it's time is spent with the camper. Our camper is on the truck full time so we opted for a custom leaf pack. It floats on rough roads but it better based on the price tag🤣

 

[rruff]

Jarring ride. Doesnt feel great for rig. I know I can speed up but often not a wise option

Tire pressure. Try 30 psi and see how that does; it will make a huge difference. And 40 psi on the highway.

Shocks and springs have a tough time responding to small high frequency bumps; the tires need to soak that up. My tires are bigger, but if I'm doing a lot of offroad I run 30 psi all the time, highway too.

 

[IdaSHO]

Just be careful about running TOO much tire for your given weight.
Big tires with a high load index, running at lower PSIs for the given weight can/will introduce handling/ride issues at speed that cannot be corrected by dampening.
Running a high load index at lower pressures will do wonders for washboard roads however

We run the highest load index LT tire offered by Toyo, the 285/75r18 with a load index of 129 and an actual load rating of 4080lbs per tire @ 80PSI.
But we are heavy, with near 7000lbs on the rear axle (5k on the front). So long highway runs I run fronts at 65PSI and rears at 75PSI or so.
Off the pavement for more than a few miles, we do drop some PSI, especially in the rear.
LONG trips off the pavement, on slow dirt roads I drop PSI 50%

To the OP, running as light as you are, able to stick with stock coils/leafs, Id suggest you dial in your tire pressures, as well as investigate better dampening (shock) options.
We run so heavy Ive never felt "better" dampening would help much. But at just 50% payload, the benefits are likely there.

 

[plainjaneFJC]

Tire pressure. Try 30 psi and see how that does; it will make a huge difference. And 40 psi on the highway.

Shocks and springs have a tough time responding to small high frequency bumps; the tires need to soak that up. My tires are bigger, but if I'm doing a lot of offroad I run 30 psi all the time, highway too.

Just keep an eye on tire temps but for sure if lower the pressures. MPG goes down a bit but it’s worth it