Couple of questions...

[goufgators]

I have a new (2017) Class C, Thor Freedom Elite 29FE on a Ford Chassis. My first question is this: At speeds of 30 to 50, there's a bumping sensation that feels like a tire out of balance. Is it possible for an out of balance tire to give that feeling only at certain speeds? If not, what could be causing the problem? Question 2: This new Class C has the notorious steering 'wander' that has to be corrected. My first attempt at resolving the problem will be to have the front-end aligned. I've read on this forum that there's a particular (is it?) camber that should be set at certain numbers. Is that correct and, if so, what should I discuss with the person doing the alignment (numbers)? Last Question: Actually, this is a continuation of #2. I know many people have added a number of things to their coaches to correct steering problems such as Steer Safe, front and rear stabilizer bars (believe that's correct terminology). I'm willing to do all of the above if it will show positive results. Please give me feed back regarding your opinions (advice) on these issues. Many thanks!

[Seon]

DrewE wrote:


...It's also possible on a motorhome especially for the drive shaft to be out of balance, which causes vibrations at different speeds than tires would.

Years ago I bought a Class A Winnebago that had that problem so brought the driveshaft to a shop that discovered it was .015" out so had it balanced. Ran smooth after that.

[OFDPOS]

To the OP
There is a thread over on the FR talk forum about the 2016 E450 vibration noise.
Apparently the 2016 E450 chassis had a problem with exactly what you /I are describing ?

They removed the drive-lines , the shop replaced the 2 center carrier bearings, checked balance on all three drive-lines , reinstalled the drive-line.
I test drove it and now the vibration is worse !!

The Ford place doesn't know what to do ...

[tatest]

Tires/wheels out of balance will be noticed most at a particular speed, and at harmonics of that speed (e.g. if noticed at 50 mph, it should occur also at 100 mph). The same holds for other rotating parts like driveshafts (which will link to road speeds) or crank assemblies (which will link to RPMs). The range 30-50 MPH is kind of broad, but an out of balance at 30 MPH should show up again at around 60 MPH.

The key alignment specification on the E-Series chassis is caster, not camber. With E-350/450 chassis RVs often heavy on the rear, light on the front, which should be at the upper end of the adjustment range, for maximum tendency to return to center. The other factor is size of contact patch on the front tires; the E-Series gets feeling really loose when the contact patch is too small, so front tires should be inflated to no more than what is needed to carry the load. The 80 PSI recommended for maximum load on the tire is way too much for the actual load on the axle.

Get the alignment and tire pressures right before spending more money on add-on steering centering devices.

[j-d]

OFDPOS wrote:
Not sure how a person would remove the axles "retest" then remove each drive-line "retest" ?

It was too late in the day Friday to go test drive it.
Will be doing that Tuesday.

I guess if it's up on stands or a lift, could pull the axle shafts to take axles/wheels/tires/brakes out of play then run it up to complaint speed. Then driveshaft could come out piece by piece till the third (rear) and second shaft (center) were out. Repeat, till only the very front shaft was still there.

A crooked yoke weld has been mentioned before. Our old 1983 E350 had that. And that coach didn't have a stretched chassis. That was an OEM Ford fail. So don't go thinking only the extension parts are the suspects!

Meanwhile, y'all have a Blessed Christmas! We headed into DEC with nothing planned. Then we were asked to read the Advent Love Candle devotion at church yesterday morning. Then last evening church friends brought us to their family dinner, instead of the Little Caesar's we'd planned. No dinner plan today turned into family dinner with my cousin. Yesterday we invited a single lady friend for holiday breakfast. While I put front brakes on her Honda...

It's all great and we're all blessed, just to experience what we share here. I pray you wake up to a smooth ride, tomorrow and through 2018. MERRY CHRISTMAS!

[OFDPOS]

Not sure how a person would remove the axles "retest" then remove each drive-line "retest" ?


The Drive-line shop found both center carrier bearings questionable and the rear two of the 3 drive-lines out of balance.
So they replaced both center carrier bearings and balanced the drive-lines.
It was too late in the day Friday to go test drive it.
Will be doing that Tuesday.

[chris_diane]

I worked with a local driveline shop to fix my 50 to 60 mph vibration problem
Here is the list of suggestions I followed to find the problem:
Put the rear axle on jack stands and in gear run the engine to the speed it vibrates.
Remove rear axles, retest, remove each driveline until vibration goes away.
Results were: the forward driveline extended by Gulfstream was not straight. I was told this is not an uncommon problem. Also tires will vibrate from sitting for long periods until they warm up after driving for some miles.

[OFDPOS]

Kinda been lurking to see what others would comment and if you had found the answer / problem fixed...

We purchased a used 2011 Winni Aspect 28B 12,800 miles on it.
On the test drive I did notice a slight low rumble noise sounded like cupped tires.
The owner mentioned he had the tires replaced just 2 months before do to the Michelin tire recall.
So I looked at the tires and noticed they were BFG Commercial tires.
Noticed the tread was a bit more open tread then the Michelin LTX's .
Thinking it was the tires causing the noise...

On our maiden shake down run noticed the noise and slight vibration came in at 53 mph and pretty much completely gone at 69 mph.

Thinking it might be the tires, I got a hold of the Tire shop and Michelin and they swapped out the BFG's for new Michelin's .
Guess what noise/vibration still there.

So I started looking online at noise/vibration concerns , came across an article about nose/vibration and causes. It mentioned drive-line drone , u-joints , out of balance drive-line to a bad drive-line itself. Yoke not being welded on centered...
The article mentioned about the vibration could cause the rear trans shaft seal to leak.
I crawled underneath the MH while doing another project and noticed the rear trans shaft seal was in fact leaking !

I brought the MH into the local Ford dealership that works on MH's.
Explained the trans leak concern and the noise/vibration I had.
Told them I had tires swapped out and it still did it.

They test drove it , verified the leak and verified the noise.
They said once they aired up the rear air bags the noise went away.
Their recommendation "run the air bags at 80psi"
I said NOPE what is the fix ? They came back with the rear leaf springs had settled,, dearched...

So they replaced the rear leaf springs , replaced the trans seal, called and said it was ready to pick up.

I didn't even make off the freeway on-ramp onto the freeway and the noise /vibration right on cue 53 mph.

Circled around came back, got another tech to go for a test drive.
He said it was Drive-Line Drone. The angles need to checked.
So I made another appointment to bring it back at a later date.

But before bringing it back to the dealer I took it back to the tire shop and had them Road Force Balance all 6 tires even tho the noise vibration is coming from the rear of the MH.

All u-joints show good, tech states the angles of the drive-lines are off, so after ordering and shimming the rear of the trans center carrier support and drive-lines , I come back for another test drive, absolutely no change.

They removed the drive-lines and they will be at a Drive Line place tomorrow having the balance checked.

This may have absolutely no resemblance to the OP question ?
But the noise I heard sounded just like going from nice street tires to off road MS tires that were cupped really bad.
It doesn't seem to change pitch of noise / vibration by speeding up or slowing down.
It just appears at 53 mph and is gone at 70 mph.

I can speed up to 75 mph ,let off the gas, put the trans in neutral and shut the engine off, once it slows down below 70 mph the noise starts and once below 53 mph the noise is gone.

[Bordercollie]

It might be a defective tire with a bulge. I have older tires develop a thump which developed into a tire losing tread. I would have tire checked for a defect,

[memtb]

goufgators, I very recently had my “caster” set on my E 450 (class c), to about +5 degrees. It helped a great deal. Prior to getting it done...it would give you quite a workout trying to stay ahead of it!

[OLYLEN]

Just had to LOL Busskipper says a lot then says don't take the advise on the forum HHHHMMmmmmm. Tire pressure, alignment, should help a lot. Go to IRV2 and the ford forum, lots of discussion on wander and cure. I did the first two then replaced the stock warn steering stabilizer and that did the trick. A good tire shop should be able to locate the thump problem, but I would do the dearer on the alignment and tires, some are stpping up without much todo.

LEN

[clayway]

This is what I would do first, my opinion only & what I did with my class c before adding any after market items
Correct tire pressure front & rear, weigh your coach & then check tire recommendations
Front end alignment
Balance all 4
Good luck, let us know what works

[Chum_lee]

How is your Class C loaded? Check the axle weights on a scale. If you have too much weight loaded behind the rear axle and too little on the front and amidship, that can change the front suspension caster angle to the point where the vehicle wanders. I'm not saying that is your problem but I see a lot of Class C RV's that are about to do a wheelie because of the loading.

Chum lee

[Harvard]

"(is it?) camber"

No, its caster and you want +5.0 or more for highway driving.

POPULAR MECHANICS MAY 1973:
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).

[Hank_MI]

Busskipper, I agree with much of what you said but not all, sorry.

An out of balance tire can dinitely only show up at certain speeds. As far as advice on this forum, well many people here have more experience with a motorhome than most truck service centers. So some good advice is available. Such as tire pressure which is seldom set by the manufacturer or dealer at the right pressure.

I do agree that the first step is going back to the dealer. Unfortunately most are not really geared to fixing chassis problems. Hopefully he can get them to send it somehwere that can address it.

You didn't mention it but class a gasser or class c both have many of the same suspension and handling issues. So I don't see that posting it here is a big deal.