Hard to stay in lane on highway?

The only hurt is paying for the check up. Yes, RVs demand more attention than a car. The longer the wheelbase the better they track. But especially with a used vehicle, go ahead and get a check up if it feels tiring to you. I also notice that as I get older I have to increase my focus.

One other thing I learned driving a small bus. I had much less wander when I steered less. Instead of constantly correcting, I found if I corrected then let loose of the wheel, corrected again and let loose again, it was a lot easier.

Some bigger vehicles are really prone to over steering until you get used to them.

That's definitely not normal behavior and should be looked at real soon, could be something as simple as incorrect tire pressure, or possibly needing a wheel alignment; take it to a good alignment shop to have it checked. RV dealers aren't of much help for this kind of matter.

The first step I would recommend is driving to some scales, get your actual axle weights (individual corner weights if possible) in your "ready to roll" configuration, and set the tire pressures according to the tire manufacturer's chart. It's not uncommon for dealers to fill tires to the maximum pressure listed on the tire sidewall whether that much pressure is needed or not.

After that, there are a variety of handling fixes which can be pursued which might help. But try the cheapest solutions first.

Good Luck,

~Rick

In the wind they can be a handful but I bet you have an alignment problem or something. I wouldn't take it to the dealer as they'll just out-source it to a FORD dealer and keep it longer than they should.

I had the same issue with my 31' Greyhawk. All tires @ 80psi, the max pressure marked on the tire sidewall. I checked the manufactures recommendation for tire pressure marked on the drivers door jam. It called for 80psi on the rear tires and 75psi in the front. Made a world of difference.

What they said above!

Print Michelin's Load-Pressure Chart. Put it in the Coach along with

Get a good tire gauge that will fit all your valves. You may find you need to replace stock valves on the rears with BORG Dually Valves but that's an extra subject

Load the RV as for a trip. Full Gas and LPG. Half tank fresh water, Gray and Black Empty. Add typical People and Supplies

Weigh on CAT Scale available at most truck stops. If you tow a vehicle have it hitched up. Scale will report that weight as "Trailer." Coach front will be "Steer" and Coach rear will be "Drive."

Set Tire Pressure according to Weight per Chart. FRONT is critical, nothing wrong with 80 in Rear. If tires are hot, go with chart + 3-4 PSI

Drive again, Report Results

“IF” it is a Ford chassis, and “IF” Ford is still using the older model front suspension design....it is likely that you need “much” more caster put into the front end alignment. This has been (for many years) an ongoing problem with the Ford E 350’s and 450’s. With factory spec “caster “ the unit has “very” nervous or twitchy handling characteristics. It can/will work the driver, trying to keep it from wandering all over. Do some research on what others ( including myself) have done to mitigate this condition. If memory serves me correctly...I think that 5 or more degrees positive caster is required to help the situation! Ours is much better....but it ain’t no Mustang GT!

What has been said is true; definitely check the tire pressures and weights and consider having the caster checked.

There should not be noticeable play in the steering, which would feel like bumps back and forth as the road conditions change. If there is, you probably have some worn tie rod ends or something along those lines that should be taken care of. I would not expect that on a 2018 with 12K miles, though; it's barely time enough for their first drink of grease.

Twin I-beam Fords prior to 2009 had the issue memtb is referring to. There are caster adjustment bushings on the market to dial in more caster on those Fords. The original poster needs to give brand information to get more knowledgeable input. Low air pressures will cause wandering. It's unusual for a unit this new and with as few miles to have wear problems. I would take it to a good alignment shop prior to going to a dealer.

Ford ships these E350/E450 Cutaways off the assembly line
with +3 to +4 degrees of Caster. Those settings are
OK for city driving BUT you want to have +5 to +6 degrees
of Caster for highway driving, OTHERWISE:

POPULAR MECHANICS MAY 1973:
START QUOTE:
If too little caster exists, the car will wander and weave,
thus necessitating constant corrections in steering.
END QUOTE:

There are at least two ways to increase the effective
runtime caster (see Self Aligning Torque):
1. Decrease the tire inflation pressure to the required
minimum for load (to increase Pneumatic Trail), and or

2. Increase the caster angle during an alignment
(to increase caster trail).

If you find an improvement in reducing the tire pressure
you will be amazed what it is to add +2 degrees of caster. IMO.

The specified range of Caster for the E350/E450 is
from +1.5 to +7.0 degrees. As you can see
almost any possible setting is "within spec"
for the "tweak the toe and you are good to go"
alignment services. Stay away from Ford
dealerships and have it done at a "good" truck front end shop.

Our experience. Circa 2010