Thor Palazzo diesel 33.4 wandering / (sway)

[johnfgriner]

Hello Everyone:
I have a Thor diesel palazzo 33.4 where the wandering above 50 mph becomes tiresome and annoying. I can only drive 1.5 hours or so and I have to take a break. It constantly requires minute steering corrections / nothing as bad as a gas motor home, however it is tiring. I cannot take my eyes of the road for more than 2 seconds of it may be in a slight drift.
I am hoping someone (a mechanic) may be at the Diesel Club Rally in October and shed some light on the issue.

History:
I bought the motor home used and to date have spent around $3,500++ on steering improvements. None of the improvements have made any difference in handling. I do like the motor home and maintenance cost has been as expected.

Improvements:
-Installed supersteer motion control devices for the airbags
-Motor home has the heavier sway bars installed on the fruehauf chassis
-Front end aligned (was at factory specs)
-Installed bilstein shocks
-Checked to see if air bag height could be increased (no)
-Installed road master steering stabilizer
-Had front end re aligned and had 8% caster put in axle (more caster reduces drift)
-Mechanic recommended Michelin tires (It had them)
-100 psi front / 110 psi rear
-Makes no difference whether im pulling a toad (5500 lb Durango) or not.

I read posts where members get gas RV’s to drive like a dream...

What am I missing?

Stumped !!!

[jtyphoid]

I think that the short wheelbase and long rear overhang of your Palazzo contributes some to the tendency to wander, but it's hard to say how much.

Our Aria 3401 has more of a tendency to wander than some longer wheelbase models that I test drove. It's one of the negative aspects of having a model that will fit where the longer ones won't.

Unfortunately, the length of the rear overhang of a diesel pusher is determined by the length of the engine, transmission, and drive shaft, so the only way to make a shorter coach is to remove length from in front of the rear axle, thereby ending up with a shorter wheelbase and some degree of poorer handling.

One thing you could do is test drive some other diesel pushers with the same or similar wheelbase to find out if the way yours handles is out of family or if they all handle about the same.

[johnfgriner]

Thanks .. The fact that you have driven different models and own a short wheelbase confirms a suspicion of my mechanic that the short wheel base contributes to wander. I never considered the long overhang which also makes sense.

It will be interesting to see other comments as they come in. Thanks again



(And to put this in context for other readers I've never driven a gas class A, B, or C where I could tolerate the sway and wander. I didn't like towing an Airstream either even with the blue ox hitch).

[TurnerFam]

John, I've owned my Palazzo 33.3, a very similar length and model floorplan, for over 100,000 miles across this country, Canada, and even Alaska, back in 2017, and have had none of the issues you describe, other than a slight 'pull' to the right during the first year, which was easily solved by Freightliner Custom OASIS Service Center, in Gaffney, SC, where the chassis is built - they simply swapped the front two steer tires - no problems since.

I will admit that you are driving with extremely high PSI tires - you should simply weigh your coach, FULL LOADED, which is with people, 3/4tank of fuel or more, 1/2 tank of water or more, food, clothes, stuff, etc., and THEN refer to your tire owner's manual to determine the CORRECT PSI levels for your front and rear tires - you'll probably find that your fronts will be in the 85-90 range, and your rear duallies in the 90-95 range - for a MUCH SMOOTHER RIDE.

I have NONE of the additional steering and suspension additions that you speak of, they are not needed. These chassis' are built for a motorhome, for this application, and the XCS chassis height is a perfect combination with the wheelbase(around 17' I believe), and actually very little 'rear overhang' compared to many other coaches, whether gas or diesel. The XCS' low stance gives it an even lower center of gravity compared to most any other coaches on the market, other than the 'twin' Forest River Legacy, or the Fleetwood Pace Arrow, or the Winnebago Forza, etc. This lower center of gravity actually helps the coach drive easier, have less movement when traveling, and less wind aggravation. It will get some push by passing semi's since it has a lighter weight of 26,000lbs gvwr, but that's simply a byproduct of the weight and size versus other larger and heavier commercial trucks, and/or the speed you are traveling and the speed of any wind, in general.

Now, I can't explain why you feel the way you do about your coach's wandering, but all of us have a different 'feel' to what driving is about, in general, and I might drive your coach and not feel the same way at all - I have some expectations about driving a 34' diesel motorcoach, and don't expect it to be like a cadillac(I owned an old smooth driving one years ago!), but I also don't expect it to drive like a gas RV, either - I've owned both.
You may find satisfaction by continuing to search for answers, but you may also find that it's just the way the coach handles, from the get go, and little will ever change that, unfortunately.

I've always commented on these forums that I've transported many gas and diesel coaches from the factories in N Indiana to dealers across the U.S., and have yet to hardly find ANY gas or diesel motorhome that handles and drives and is a smooth ride like my OWN Thor Palazzo. Those brands include Newmar, Fleetwood, Forest River, Coachmen, and the like, and include even the tag axle models.
The only exception was when I picked up a personally owned Palazzo 33.3 from a customer, to transport to a different location - it drove just like my own, and the owner had added nothing to change anything. It drove great.
I would add that the Fleetwood Pace Arrow comes close, and even some of the larger, longer tag axle coaches do, too, as they have a longer wheelbase, and the weight can seem to help keep them more stable.

Our Palazzo also averages about 12.4 without a toad, and 11.4 with... this is a great advantage as the other coaches I've transported got nothing close to that, especially the gas RVs and the longer, larger tag-axle coaches. Most of those were 8-9 at best.

I think if you adjust your tire PSI, you may find an immediate change in your perception of how it drives and handles. How fast you drive is going to play into the handling, too, as I don't drive the speed limit or try to drive in a hurry - I let traffic pass me versus passing them - that's just my driving style.


I hope you find the 'sweet spot' for your coach... : )

[johnfgriner]

TurnerFam,


Thanks very much for your very detailed answer to my situation. I will lower the tire pressure and post the results. If you are ever in the area I would be happy to hire you to drive this coach to get your impression of it. I don't mind a rough ride but wandering is something I am very uncomfortable with. I'm a 2-3 day trip person at most so a 300 mile radius is all I'm good for without becoming exhausted. I'll drive 500 miles in a car.

[TurnerFam]

sounds good, but also look at taking a trip to Gaffney, SC..where the Freightliner service center there will put you up at their 50amp full service park and take a look at your chassis and suspension - they are the ones who built it, so they are the professionals who can probably best diagnose any changes you may can take advantage of. The park is free, and really is free to ANY freightliner customer, whether they are getting service there or not...use it if you are passing thru.

If you do decide to go there, you can certainly show up without a prearranged appointment, and they'll see you if and when they can, or you can call them and get on the schedule for the day(s) you'll be in the area, or just passing thru... : )

[johnfgriner]

Turnerfam

Thanks for the advice on lowering the tire pressure. The ride is a bit smoother, undecided if it helped with the wander. I’ll have a better feel for it on a longer trip.

I do remember at my 1st alignment they greased the front end which improved the wander a touch.

I got underneath and had copilot rock sterling back and forth. No visible play in steering parts. (I read a post from someone with a Monoco where the pitman was about to fall off and handling improved when it was fixed )

The forum is great. Thanks for your advice.