Newbie Question on 38A handling

[Harvard]

In case tire pressure does not resolve the wandering:

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:

[Oscarvan]

Yes, a bad alignment will cause trouble.

There are arguments that the chassis is aligned when it leaves Freightliner and that after Forest River adds 20,XXX pounds it should be done again. They don't. I have heard that FR will pay for it if you insist. (IF you can get a hold of them.)

Personally I think mine is fine, and after 24K miles I see no evidence (uneven tire wear for instance) to the contrary.

[po 185]

use them for stability and not for fuel mileage. when a semi passes me it does not push me all over the road like it did before i installed them

[Oscarvan]

Interesting, did not know it affects stability. There's a LOT of truckers claiming they do out there...

I assume you put them on the rear edge?

Also, because of the reduction of the vacuum behind the vehicle there is less dirt that escapes the air stream and settles on the coach....

Hmmmmm.

[po 185]

yes on the rear. I could not put them on top because they need a flat surface at the rear. and. they do keep most of the dirt off of my toe pick up which helps. the trucking company wanted them to help on fuel mileage which i didn't see hardly any

[Oscarvan]

Ya got me thinking. Mostly for keeping the dirt off the back. Don't care about the cap, it's the crap going into my engine bay I hate....

They are also paintable.... Couple of cans of the right color and I can blend them into my paint scheme.....

Hmmmmmmm......

[po 185]

oscarvan

you might check in on centramatic wheel balancers i put them on front and rear and dont have to worry about the tires . they stay in balance

[Oscarvan]

Originally Posted by po 185

oscarvan

you might check in on centramatic wheel balancers i put them on front and rear and dont have to worry about the tires . they stay in balance

I have them on, see my blog. No problems with balancing.

[gordonsick]

Originally Posted by DarrellT

We recently purchased a slightly used 2017 38A. We haven't had a chance to get it out and use it yet, won't until spring when kids get a break from school. It has been too cold out the past few weeks for me to go crawling around under the RV, but does the coach come with a sway bar? This is our first RV, have had a fifth wheel for years, so maybe it is just getting used to it, but i noticed on the 2 hour drive home from the dealership that boy did the RV wander on the road. Every road seam, underpass, car passing me, i had to really work to keep it centered. I have read on here where people have added an aftermarket sway bar and trim function. Do they make that big of a difference? The other thing i noticed was how heavy the gas pedal was driving home. My calves actually got tired, i had to turn the cruise on. Is that normal or is there an adjustment that can be made? It just felt really stiff.

Going back to the original post about sway bars, some things have not been discussed.

All of our Freightliner coaches have a front sway bar, as is common in cars and light trucks. Sometimes cars don't have a rear sway bar, or just a lightweight sway bar. That's because sway bars control body lean, and in small vehicles, most of it is from the front, partly because they are front-heavy. But, in a motorhome with dual rear wheels, it is clearly rear-heavy, which suggests that a rear sway bar is a good idea.

Your 2017 model should have a V-Ride Chassis, which is supposed to limit body lean on the rear, so it is the case that you have a sway bar on the rear, as well.

Freightliner switched to V-Ride in 2016 or so, so my 2015 chassis does not have a sway bar on the rear. I'm thinking of installing the Source Engineering sway bar that I can get from Henderson's SuperSteer at https://supersteerparts.com/product/...sway-bar-1-34/

–Gordon

[gordonsick]

Originally Posted by Harvard

In case tire pressure does not resolve the wandering:

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:

Yes, caster does give you the "return to centre" effect that stabilizes steering. But, it also makes steering a straight line in a strong cross wind to be very tiring. I've written a discussion about these issues at http://www.forestriverforums.com/for...ml#post1928384

I installed a SafeTSteer steering stabilizer with the Henderson SuperSteer Trim unit to stabilize the steering in situations where there are potholes, or wind gusts. The Trim unit also works to reduce the driving effort in a strong and steady cross wind. I discuss this at http://www.forestriverforums.com/for...it-170436.html

With this SafeTSteer and Trim Unit, I could live without so much caster. But, I'm not about to ask for an alignment change to take some of it out. Caster doesn't hurt, but it doesn't help so much, now that I have the SafeTSteer and Trim Unit installed.

[Oscarvan]

Originally Posted by gordonsick

Your 2017 model should have a V-Ride Chassis, which is supposed to limit body lean on the rear, so it is the case that you have a sway bar on the rear, as well.

Not even sure you CAN add a sway bar to the V ride.... There's a lot of big metal back there.

[dave-g]

On my coach the previous owner install a blue ox true center-


TruCenter Steering Control | Blue Ox | Blue Ox


It has a "trim" feature that if driving in a crosswind will allow you to recenter the wheel to offset the cross wind. It also helps in roads with a heavy crown.


I have never driven a call a with out one- but I can tell you I use it a lot.

[gmknapp52]

There are a lot of opinions about air pressure. So, this is what I've learned and experienced. A few months after we bought our 2017 38A we attended the 2 day Beginners Camp Freightliner in Gafney, SC, and Mike the instructor, the most experienced diesel person I've met, insisted on these factors when considering air pressure. First the weight over each axle was a critical factor in determining air pressure. Second you had to consider the tire pressure limits set by the tire manufacturer (their formulas are online) for your specific tire. And third you had to take into consideration the cold temperature before any sun hits your tires in the morning before you drive. And yes, all the tires on a given axle had to have the same pressure.

So if you haven't gotten a CAT scale weight of your 2 axles, with the rig fully loaded, then make a point to do that this spring when you take it out. Have full diesel and 1/4 tank fresh water when weighed. I would also recommend that for peace of mind with you and your family in the rig, get a tire pressure management system installed so you can monitor your tire pressure while driving. This will help you be aware of any potential dangerous situations.

So my SOP is to check the TPMS readings the morning before, so I can be aware of the changes i need to make, then early on departure morning I adjust all tires based on the above information. External temperature and altitude will affect your tire pressure so you have to check it daily. We could leave Michigan where it's 40 and the next morning its 65 and the tire pressure has to be adjusted.

[RKNOLA]

Berkshire owners are very helpful

[DarrellT]

Thank you everyone for the helpful information. My original post may have been a little misleading. I was interested in the steering stabilizer addition. I did purchase a Safe-T Steer and will be working to put it on tomorrow (wish the barn was heated!!).
You all make some real good points and great information provided. I will be sure to check lower the tire pressure. When we picked up the coach I remember the dealer had the tires set at 105 lbs, so I might need to lower it. I will make sure to scale the rig before our first trip from Michigan to Hilton Head this spring.