Tire Ride Contribution - Urban Legend?

[Dave-Oh]

As some folks here know, I've been trying to get the vibration in my Motorhome fixed (see Loose King Pins? post if you can bear it)- it's a year old as of Nov 1, 2015. I ask about the tire contribution as two mechanics, one at the Goodyear Wingfoot Truck tire service store and one at the light truck and RV repair shop where I got an alignment both said this could be the case.
The Goodyear mechanic said he'd seen plenty of customers come in with vibration issues repeatedly and when they switched brands the problem stopped.
The light truck mechanic told me, after the alignment and install of Centrimatics didn't fix the vibration, was that this was "all tires" and that Goodyears were commercial truck tires with sidewalls that are way too stiff for RV use. He suggested that I run the rig with lower than recommended tire pressures to get a smooth ride, or switch to Michellin tires with more compliant sidewalls.
Goodyear had set my pressures to 105psi. I reduced them to 85psi - recommended by Thor and the Goodyear Charts. No change.

Is there any data, aside from urban legend, that would support tires being too stiff and creating vibration?

1. My tires have been rebalanced multiple times, road-forced, swapped and clocked, GY replaced ALL of the tires after the dealer had replaced the front ones. King pins replaced, driveshafts rebalanced, alignment done, and Centrimatics added to no avail.
2. The Goodyear vs Michellin vs other debate is ubiquitous.
3. I don't think, from a safety point of view, I should run much lowers pressures
4. Not sure what else it could be (carrier bearing, u-joints, wheel bearings, ?).

I'm really done with trial and error - is there any data out there that would point to tires alone? How to diagnose?

Obviously Ford is lost and GY has stepped up and changed all of my tires and the road forcing didn't reveal any out of spec units (don't think anyone checked runout on the rig, though). So in case my pursuit of Ford doesn't result in a fix or replacement, what would a next step be? And is there data to support it?

[stuhly]

Have you checked the drive shaft and U joints for alignment and balance.

[Pigman1]

Sounds like you have had the tire and wheel issue covered. Has anyone looked closely at the drive shaft, hanger bearing if you have one and the universals? If the driveshaft was installed so the universals are out of phase it can also cause a vibration. I'd check the entire drive shaft closely on the chance you threw off a balance weight on it. You should be able to see the weld spot if one is missing.

[Dave-Oh]

Ford had the driveshafts removed and rebalanced. They were reinstalled with no overall change. I have asked about pinion angle and u-joint phasing and was assured it was all "checked".

[gbstewart]

other things can cause vibrations, a torque converter can cause this, had it happen to me on a old truck, wouldn't lock up and caused a vibration at certain speeds, cooling fans out of balance, broken ,loose, motor and tranny mounts, even a engine misfire can vibrate.
gbstewart

[Dave-Oh]

Agree with all so far: but is there any way of diagnosing tires - not out of spec runout, not balance problems, but TIRES/Stiff sidewalls/some unknown, mysterious issue with tires as causing the vibration?

This comes up on various forums, tires are changed and no more problems.....Is there a magic diagnostic test that doesn't involve paying out over a grand to see if it might work?

Just curious, really.

[rapid rick]

Have you tried taking off all 4 wheel covers and then drive? I had noise coming from mine not vibration,I glued epdm 1" wide to back of all 4 covers,at outer lip,where it hits outer lip of rim,noise went away.Ill fitting covers might vibrate,just a thought.

[frankdamp]

When we got our Georgetown 325, it was 8 years old and had 12,000 miles on the OEM Goodyear tires. The tires were very noisy and ran roughly. The day after we bought it, I went to our local Les Schwab store and got a set of 6 Toyos installed. It was like switching from a Model T to a Bentley!

Four years and 6000 miles later, they were still in great shape when we sold the rig. Never had any problems with them. I wish we could say the same about other aspects of Georgetown ownership!

[deandec]

I replaced Toyo with Toyo 8 years ago.

20 rear tire dismount and remounts, with 6 different tires, various forms of tire balancing, 4 different dealer shops, and 4,000 miles later, the Dealer refunded my money and applied it to a new set of Bridgestones.

The rear axle no longer had a vibration.

Apparently, I just had a bad run of Toyo tires.

This month, with the same dealer, I replaced the Bridgestone tires with Toyo tires and the new tires also run perfect. (Neither set had/has balancing applied on the rear axle.)

[Gary RVRoamer]

Is there any data, aside from urban legend, that would support tires being too stiff and creating vibration?

I don't see how there could be. Stiffness doesn't cause vibration. If it causes anything, it is, well, "stiffness". Many people claim a certain tire brand is harsher or softer riding than another, but I don't think I've ever heard of anyone claiming vibration except from a faulty tire (out of round, damaged, etc.). And you've pretty well eliminated that as a cause by replacing the tires as well as other actions.

However, wheels can be out of round or bent. So can the hubs.

[OLYLEN]

Might do a search on the vibration issue. I think I read it in the Ford section here. It sounded like just 2016's but who knows. Seems the driveline angle was the problem.

LEN

[GA Navigator]

The frequency of the vibration should help to diagnose the source. Tires and wheels spin pretty slowly. Driveshaft spins pretty fast.


1994 Holiday Rambler Navigator
Cummins 8.3
Allison MD3060

[FunGus]

If you have a dealer that is willing to work with you and committed to repairing the issue, what about swapping out all the tires and rims with a known good unit? I.E. they have a same or similar unit on the lot that drives good with no vibration and the same or similar tire size and rims, just unbolt the good wheels/rims and put them on yours and go for a drive. Vibration gone= tires or rims bad, vibration remains= keep looking (but at least tires are definitively eliminated as a cause). Or plan B could be to hit up a friend that has a similar coach to borrow their wheels for a bit

.

[JohnH12]

Originally Posted by Dave-Oh

As some folks here know, I've been trying to get the vibration in my Motorhome fixed (see Loose King Pins? post if you can bear it)- it's a year old as of Nov 1, 2015. I ask about the tire contribution as two mechanics, one at the Goodyear Wingfoot Truck tire service store and one at the light truck and RV repair shop where I got an alignment both said this could be the case.
The Goodyear mechanic said he'd seen plenty of customers come in with vibration issues repeatedly and when they switched brands the problem stopped.
The light truck mechanic told me, after the alignment and install of Centrimatics didn't fix the vibration, was that this was "all tires" and that Goodyears were commercial truck tires with sidewalls that are way too stiff for RV use. He suggested that I run the rig with lower than recommended tire pressures to get a smooth ride, or switch to Michellin tires with more compliant sidewalls.
Goodyear had set my pressures to 105psi. I reduced them to 85psi - recommended by Thor and the Goodyear Charts. No change.

Is there any data, aside from urban legend, that would support tires being too stiff and creating vibration?

1. My tires have been rebalanced multiple times, road-forced, swapped and clocked, GY replaced ALL of the tires after the dealer had replaced the front ones. King pins replaced, driveshafts rebalanced, alignment done, and Centrimatics added to no avail.
2. The Goodyear vs Michellin vs other debate is ubiquitous.
3. I don't think, from a safety point of view, I should run much lowers pressures
4. Not sure what else it could be (carrier bearing, u-joints, wheel bearings, ?).

I'm really done with trial and error - is there any data out there that would point to tires alone? How to diagnose?

Obviously Ford is lost and GY has stepped up and changed all of my tires and the road forcing didn't reveal any out of spec units (don't think anyone checked runout on the rig, though). So in case my pursuit of Ford doesn't result in a fix or replacement, what would a next step be? And is there data to support it?

The only thing I can offer may be dated but here goes:
We bought a new 35' Pace Arrow in 1999 that gave a white knuckle ride that was so bad we almost stopped travelling in it. The Ford dealer was ready to throw up their hands and say we just had to live with it.
I filed a Lemon Law complaint and it seems like the whole Ford world suddenly came awake.
They flew in a specialist who had the dealer recheck the rim runouts under his direct supervision. They found them just slightly out of specs so they replace all of them, including the spare.
He also had them installed a Safe-T-Plus and put new Michelin tires all the way around that had a load rating one up from the original. They re-weighed the rig and adjusted the tire pressures per the Michelin charts for those axle weights for the new tires.
There was no one thing that fixed the problem but the combination of everything fixed the vibration so the rig was driveable.
During the final arbitration meeting Ford also paid us $5000.00 for our troubles and loss of use for the 6 months it took to resolve the problem. They would have bought it back but we opted to keep it since we liked everything about it except the vibration problem. Once that was gone we enjoyed several years of travel with it until we sold it in about 2007.
I don't know if that helps but you may want to look at the Lemon Law regs for your state. In my case it sure got their attention.