Alignment shop wants to start with front sway bar only??

You may have read that I visited The Mountain of RV Handling Knowledge, Hendersons Line Up in Grants Pass OR, and had an audience with the Prophet of same, John Henderson. We talked mostly about alignment, but my recall is that he liked Front End Alignment With Caster and/or Safe-T-Plus Damper/Stabilizer AND a Rear Sway Bar.

From my personal experience, I'd install Hellwig sway bars Front and Rear. You have a late-model chassis, 2008 or newer, right? The OEM front bar is better executed than 1992-2007 but still undersized. The rear sway bar is the same from any E-Super Duty or E450 regardless of model year. So if you want to cut your cost a little, my take would be Rear, and use Hellwig, much less expensive than Roadmaster for the same thing. By all means, do the front too if you can.

You have Alignment. You're adding Sway Bar(s). This is all good. Have you also weighed the coach and adjusted Tire Pressures?

I thought you had a late model E450. Signature doesn't say but reviewing posts suggests:

Late E450
Roadmaster RSSC Stabilizer/Damper
Front Tires around 60-65 PSI for 4400 front axle weight

When a Ford Twin I Beam chassis sways, it Steers! The Rear End is the Heavy End. No wonder the Brits call it "The Big End..." That's why I think you should control sway starting back there.

Also, with the late E450 using an improved Front Sway Bar DESIGN (not size, still too small) you "might" find the end link bushings are soft rubber. You could replace those with hard bushings, polyurethane, and maybe gain a little more control.

Still, I upgraded both, and added a Blue Ox Tiger Trak rear track bar. I'm glad I did all of those, but if I was to do two of the three bars, they'd both be Sway Bars.

You'll also find your coach has a steadier stance on the campsite...

I just replaced both front and rear sway bars with the Hellwig bars. It feels much more "planted" when driving and more stable. I had only the factory installed sway bars and these hellwig units are much bigger and stronger. I think you will feel a difference but don't know for sure as I did both instead of one at a time.

I think JD is right probably the rear has the most effect. But I'd do both if you can. Also on those Bilsteins did you go with the HD model? I think these chassis need all the help they can get to keep from swaying (equipped as a class C). He's right..when they sway they steer.

I only did the front on mine, to eliminate the toe changes and resulting bump steer that occurs as the Twin I-beams go through their range of travel. Worked out exactly as I wanted. An E450 already has a substantial rear sway bar, much thicker than the wimpy OEM front. Also the late model E-Series chassis (08 and up) have heim-jointed front sway bar end links. No rubber.

Get another alighment shop. A truck alighnent shop that knows vans.

If the price is a dollar more to install separate then get them both at once.

I seem to recall that the normal alignment specs call for about *3.5° however this created a "worn out steering" effect in a rear heavy motorhome and that *5.5° caster created a night and day difference for most people who posted about this. Make sure your alignment shop understands this, or you won't have gained a thing.

Charles

Have you weighed your RV loaded as it would be for a trip?
If you do not have at least 80% of the max front axle weight on the front axle it does not matter how much money you spend on alignments, steering stabilizers, shocks, sway bars or exorcisms you will have handling problems no if ands or buts. In addition without knowing your weights your tires are probably not inflated correctly and that can also cause major handing issues.

When in doubt, run all the tires at max pressure.

Soft rear springs can cause alot of rocking, sagging, swaying issues. Most motorhomes are overloaded and need stiffer rear springs, especially those chassis which have alot of rear overhang length.

You can get a set of heavy duty leaf packs from SD Truck Springs or Stengel Bros.

Yes, heavy sway bars front and rear, with polyurethane bushings, will certainly help.

First ensure that your steering box, tie rod ends, ball joints and axle pivot bushings are all good. If any of those are bad, it doesn't matter what aftermarket stuff you add, it will still have poor steering and handling.

On the alignment, lots of toe-in and caster are a good thing.