Ford 350 chassis handling

[rvit]

I have a 2014 Pleasure Way Pursuit on a Ford 350 chassis. We love the rig and have put 7500 miles on it with only one nagging concern. It is difficult to drive, requiring constant attention and corrections. I have seen others mention this problem with this chassis so I had believed up until now that it was a characteristic of this chassis.

But when I took it to the Ford dealer and asked if there was anything that could be done, I was informed that the unit is 1 1/2 inches lower in the back than in the front, resulting in wearing tires and they believe causing my directional issues.

Has anyone else experienced anything like this? There is some question whether PW is going to cover this as Ford has said they won't. At only 22' I don't really understand since I know much longer rigs are built on this chassis without this issue.

[tpi]

It's on the list. I've chatted with them and they said they'd set to my request or as close as they could. It probably will be one of those things I tie in with other service, once it is in shop at some point.

Harvard good that you're pushing that. I can see nothing but benefit here. The time to do it is when you take it in for first alignment. Unfortunately in my case I didn't know to specify that setting at that time.

[Harvard]

and I am guessing you could have +6.5 if you wanted to go there. 🙂

I am not saying that there are not a lot of disturbances in the over all handling of the E series, but I am saying that more +caster lessens the effect those disturbances have as we move down the road. And yes, I admit, my agenda is to sell +caster. 🙂

[tpi]

Harvard I don't have it in front of me but when I had alignment done it was in the plus 4 to 4.5 range with one side somewhere around 4.5. The rig appears level, when weighed without people in it there was 3800 on front and 7300 on back. E450. Tire pressure at 50 PSI front. Next time I go in for alignment I'll request as much caster as they can dial in-it would help on center feel, return to center, and improve tracking. Straight ahead tracking hasn't been biggest concern, my quibbles are with steering non precision tied to roll-something I found significantly improved by Roadmaster Sway bars. Track bar less so but still represented improvement. I think heavier shock valving would help too, but I haven't gone there yet. Again-this all may be something that hits me and could be less for others.

[Harvard]

tpi wrote:
The more I drive mine and think about it, the more convinced I am that there are numerous feedback cues given to the driver by any vehicle. How we relate to them, interpret them is very important for our perceptions of the handling. It is my view that two people can drive the same vehicle and come away with different opinions on how it handles. This is more noticeable with RVs, but check out auto test reviews and look at the differences of opinion on some cars.

I think if the handling seems good to you, there is no need to question that at all-drive it and enjoy it. OTOH when reading someone's concerns about handling it is very possible the issues could be with the idiosyncrasies of the Ford chassis once the alignment, loading, and tire pressure issues are sorted out. Some people may have to go with the sway bars, the track bars, shocks, etc. even on the smallest class C motorhomes to try to get best possible results for them.

One thing if you're in the "its not that great handling camp" like I am, do have a realistic view of what a big box on wheels can be. In my view these things suffer from roll related steering issues and anything to tighten up body roll will make the steering more direct. But there's a limit and there's no point in obsessing over these issues. Drive at a comfortable speed and enjoy the journey.

Well said tpi. But perhaps to better understand the real world, I am curious about the current caster settings (as well as any nose up or nose down profile if not neutral) on your particular Ford?

[tpi]

The more I drive mine and think about it, the more convinced I am that there are numerous feedback cues given to the driver by any vehicle. How we relate to them, interpret them is very important for our perceptions of the handling. It is my view that two people can drive the same vehicle and come away with different opinions on how it handles. This is more noticeable with RVs, but check out auto test reviews and look at the differences of opinion on some cars.

I think if the handling seems good to you, there is no need to question that at all-drive it and enjoy it. OTOH when reading someone's concerns about handling it is very possible the issues could be with the idiosyncrasies of the Ford chassis once the alignment, loading, and tire pressure issues are sorted out. Some people may have to go with the sway bars, the track bars, shocks, etc. even on the smallest class C motorhomes to try to get best possible results for them.

One thing if you're in the "its not that great handling camp" like I am, do have a realistic view of what a big box on wheels can be. In my view these things suffer from roll related steering issues and anything to tighten up body roll will make the steering more direct. But there's a limit and there's no point in obsessing over these issues. Drive at a comfortable speed and enjoy the journey.

[pnichols]

EMD360 wrote:
Our 22' 350 has new tires but no other modifications and it drives easily. It appears you need to find an expert who will actually find and correct the problem.

Richard, that's good advice and what I would recommend also ... especially since your motorhome is only 22 foot, which I'm surprised has any handling problems. There is definitely something wrong there.

I have a 24' Itasca on the E450 chassis and on the door specifies 65 lbs. front, 80 lbs. rear, for tire pressures. Those are the pressures I use in the tires and it handles beautifully even though the motorhome loads the chassis well below it's maximum. I like tires inflated on the high side of what inflation charts specify because higher tire pressures lengthen tire life.

I did have it aligned after having the motorhome for awhile, but not because of any handling problems as it was OK since brand new. For the alignment they did have to add some beveled shims to the front suspension ... probably correcting what others have mentioned in this discussion.

[Harvard]

But, be fore warned, not all "experts" are created equal.

For example, see this caster specification:
2011 E350/E450 Alignment Specification

Notice how the specification for LH and RH caster reads:

LH 3.90 +/- 2.90 Degrees
RH 4.30 +/- 2.90 Degrees

If the LH is found to be +3.90 and the RH is found to be +4.30 degrees most alignment techs will interpret that as good to go, bang on.

NOT SO !!!

In reality, I would want LH +5.90 and RH +6.30 but I might have to stand my ground to get what I want depending on the "experts" opinion. Buyer beware.

[EMD360]

Our 22' 350 has new tires but no other modifications and it drives easily. It appears you need to find an expert who will actually find and correct the problem.

[Harvard]

1.5 Inches in 22 feet (264") only amounts to 0.35 Degrees. That is peanuts. IMO

[Harvard]

Fore to aft does play a role in the effective run time +caster.

For example, my 2004 E450 has a nose down of 1 degree. This reduces my effective run time +caster by 1 degree. My unit runs at LH +5.3 RH +5.5 caster. It was a nightmare when I was running at +3.3/+3.5 caster. Adding the +2.0 degrees of +caster made it a different driving experience.

And yes, tire inflation pressure also effects the runtime caster trail, less pressure results in better stability BUT nothing like the difference of adding +2 degrees caster to what ever you have now.

[j-d]

That thread's a good one. As noted there, for openers:

What are the Coach's Length and Wheelbase?
What are the Front and Rear Axle Ratings (GAWR) and what are the actual weights per a truck scale?
What are your Tire Pressures?

Ford's position on this? Low REAR ride height? If it's new and low, I'd guess it's close to max axle rating on the rear. That might mean it's light in front, or at least that the front tire pressures could be too high. If you meant the REAR is low, that's more unusual than the rear being high. If the rear is low it might be too soft for the load. If it's too soft for the load, the REAR may wallow and sway. In a FORD chassis, rear sway or rolling causes an unwanted steering action in the front. Hence my questions...

As Bryan aptly mentions, excess front tire pressure can run from annoying to disastrous. Make sure all four rears are inflated to the door sticker pressure. That'd be max load and it's possible that's what's on the rear. The front tires shouldn't be over 60 or 65 and that's for max load. I'd be very surprised from what you're reporting that the front axle is anywhere near max load.

[carringb]

There is no reason it can't be aligned properly at the existing ride-height. In fact, most E450s ride tail-high, its just many MHs ride flat because they are so heavy.

But... before digging into alignment, have you made side the front tires are not over-inflated? They should NOT be at 80 PSI.

[rvit]

Actually, the rig is most comfortable on the back roads up to around 50 mph. It's highway speeds where it gets tedious and it can be a real challenge to keep it between the lines if it's windy enough.

This is my first RV of any kind and I assumed that this was normal. But the Ford dealer says he can't align it with the chassis tilted front to rear. Pleasure Way wants to provide Ford with alignment settings for this unit without dealing with the "ride height" as Ford calls it.

Is that plausible? Can alignment settings alone offset the effects caused by the ride height difference.

[tpi]

There's a ton of handling threads here-definitely read up..

Summary:

1. Try to load as much weight low and forward as possible
2. In the handling threads you'll find reference to Michelin tire inflation chart which is based on weight at the wheels. Weigh the vehicle and follow the recommendation. Particularly in regard to front tires. You don't want them to be overinflated.

3. Wheel alignment with emphasis on max positive caster. You'll see that in the threads.

4. I found the heavier sway bars and track bar to be beneficial, but you want to do that last after trying all the cheaper ideas.

5. After all is done, come to an acceptance of the handling. It aint no sports car or even close. Slow down, enjoy the ride, drive in the vehicle's comfort zone. You will not be able to keep up with auto traffic on winding roads, accept it and let them pass.