Class A Handling issues

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WinterAdverse

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Joined
May 3, 2017
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26
I am trying to find something to improve the handling of my Thor Hurricane 31s. At highway speeds, 55+, it tends to wander in the lane and is pushed around by crosswinds and passing semis.  Regarding the highway speed: typically the higher the speed the worse the handling. A note on that, I don't like to go over 65 mph, mainly as a mileage consideration. I have been researching stabilizers, track bars, etc... on the internet and various Forums such as the this forum (probably the best IMHO), the RVUSA Forum, Thor Forum, iRV2 Forum, Camping World/Good Sam plus reading about Super Steer, Roadmaster, Blue-Ox, Safe T Steer, and various Ford F53 with a Class A solutions. What I have discovered is that the solutions, advice, and recommendations run the gamut from minor to major. Some say lower the tire pressure below the recommended or raise the tire pressure to 110 psi, the tire rims are too narrow, get different tires, add shocks or air bags, a steering stabilizer will fix it, or maybe not, a rear track bar is needed, a front track bar is needed, a front or rear track bar won't help. Also there is discussion about how the F53 was not designed to be used for motorhomes, Thor under designs their units,  Essentially the information is confusing and frustrating. Are there any owners that have had success with some of the after market solutions? I realize that a person has to pay for good results but there has to be a reasonable, cost effective solution.
 
You need to get the proper amount of air in your tires. Too much air will cause all the problems you are having. Take your RV to a public scale (Flying J) and get it weighed. Then go to the manufacturers web site and find their tire inflation chart. Most beginners inflate their tires to the number on the sidewall which is dead wrong, that is the maximum you can inflate to not the recommended pressure. That number is different for each RV and each set of tires.
 
Hi, Thanks for the comment. I have weighed the unit, loaded and with the tow vehicle attached. I have the tire pressure at the recommended pressure plus a couple of pounds. The psi was originally at 105 and I gradually reduced it to what I now have (84) and it did make a difference. Also I have had the front end aligned and that provided some improvement. I still think the handling should be better though.
 
Yup.  Tire pressure first - you did that.  There are almost countless conditions that can cause the problems you described.  In order, generally, the most helpful for most folks that own a coach on a Ford F53 chassis, is better front and rear swaybars.  Then a rear trac bar and steering stabilizer. The newer F53s have front trac bars.  There are other aftermarket add-ons you can get as well.  Like you seem to have noticed, not cheap.  You can try the handling fix as talked about at length on the IRV2 forum; zero cost, and if it helps, that's one thing you know you need to address, sway bars.  That was my biggest improvement, then a rear trac bar and steering stabilizer.
Make sure you cover your butt about the warranty, if you make changes to the chassis.
 
I think the best upgrade for the money is a rear track bar. You need to stabilize that rear overhang as that is a big leaver that pushes the front around.
Bill
 
We have a 2008 Thor Outlaw that is 37 foot long on the F53 Chassis.
When we bought it and drove it home from La.  , It was scary !!  65 or 70mph and it would start
tipping back and forth untill you slowed down to under 60mph.. 
  And if a semi-trailer passed you, it would shove you over 6-8 feet !  Very very Scary feeling..

Well after I got it home and started checking it out, I found the rear sway bar was unhooked at one end and
the bracket was bent and there was NO bushings left in the brackets..  So I bought new bushings, straightened
bracket out and rebolted the whole thing back on and lock-tited the bolts..
  Huge difference !  Much much better with no tipping back and forth and only getting pushed 2-3 feet by passing Semi's..

Next, I did the cheap no cost mod.  I moved the sway bar arms from the outside hole to the innner holes as many have done
and again, A big differnce..  Much more stable ride and now passing Semi's hardly bother us at all....
  I still feel that they need a larger rear sway bar as the rig is so tall  (13 foot) and still moves more than I like, But I can live with
what I have now...

  I dont know if your newer Thor F53 has the sway bar on the rear or not. But if not, that is something I would strongly recommend..
And our rig weighs about 24,000lbs and we run 80psi in our tires..

Bob
 
WinterAdverse said:
Hi, Thanks for the comment. I have weighed the unit, loaded and with the tow vehicle attached. I have the tire pressure at the recommended pressure plus a couple of pounds. The psi was originally at 105 and I gradually reduced it to what I now have (84) and it did make a difference. Also I have had the front end aligned and that provided some improvement. I still think the handling should be better though.

You are doing things right. Air pressure, then a good alignment. I did the same thing to my 2007 Damon on a 20,500 pound chassis. It was much better but when I added the rear trac bar it was huge as far as handling side winds and trucks. I never did the cheap handling fix because on my coach at least sway was not a problem.
 
I am weighing in about 19000 lbs fully loaded pulling a single axle trailer    F53 Chassis... I done the CHF on both the sway bars..Installed Firestone Air bags and run tire pressures at 65lbs ....even the DW enjoys driving the rig now...
 
Had a similar situation with my Damon UltraSport. Went to a super steer shop Mainline Truck and Trailer in Cleveland Ohio. Had a road performance assessment done. They road test the coach. Check all the suspension parts and weight all 4 corners of the coach. Then make recommendations. I had tried to self diagnose with no luck. Their recommendations are rated as what is most important. Best $145.00 I ever spent on the coach. If they do the work all or part of the fee is applied to the final bill.
 
utahclaimjumper said:
Have the CASTER adjusted more POSITIVE BY TWO DEGREE'S.>>>Dan

POPULAR MECHANICS MAY 1973:
"If too little caster exists, the car will wander and weave, thus necessitating constant corrections in steering."
 
Well, I will try this again since my previous reply apparently didn't get sent. First I want to thank Gary for the link to the the article in the Library. It was very helpful and cleared up a lot of things for me. Also want to thank everyone else for their comments. I am apparently at the beginning of a steep learning curve. I did some stretching exercises and then crawled under the the motorhome to see what is actually there. It looks like there is a factory installed sway bar on the rear axle and also one on the front. Additionally it looks like there is a factory installed track bar on the front. There is a bar that connects from the passenger side frame to the front axle, with appropriate bushings, and I assume that is a track bar. For additional info, both the coach and the chassis are 2017 models. I am starting to come to the conclusion that perhaps I should first try a rear track bar or a supplemental rear sway bar. The sway bars look to be pretty substantial though with the front thickness measuring 1 3/4" and the rear at 1 5/8". The front track bar appear to have a thickness as least as great as the front sway bar. Another possibility is perhaps after market springs or shocks but after reading Gary's article I am not sure that would provide the improvement I want. Opinions are welcome.
 
SeilerBird said:
I think your problem is all the crap that was added on. A stock RV should not need add on accessories to make it drive properly.
I don't think anything has been done to his yet as it is a unfortunate reality that the manufactures don't do a better job.
WinterAdverse, The sway bars control side to side roll or rocking. One cheap upgrade (if you don't already have them) is polypropylene sway bar bushings as they are firmer than the rubber ones.
The track bar for the back will stabilize the side to side (fish tailing) caused by the rear overhang.
Speaking of that watch out for "tail swing" when maneuvering in tight places, like gas stations. Don't get to close to the pumps and don't turn to quick or sharply when pulling out. ;)
Bill
 
SeilerBird said:
A stock RV should not need add on accessories to make it drive properly.

True - but sadly not the case with the majority of the Ford F53 Chassis' in use.  I think it should be on the coach builder to do what is necessary to make things right; Ford has no control over what someone does with their bare chassis, nor can they possibly make "one size fits all".  (or in the case of the F53,many sizes).
 
I guess I'm a slow learner. I have been looking at the CHF solutions and can't help but think that there is some reason the design engineers wanted the sway bar connections in the outside hole rather than the inside. I keep thinking if I move the connections to the inside hole I would be defeating some design/safety issue. That being said, the CHF on the front looks like it is a nonstarter with my chassis. In order to move the connections I would have to raise the ends of the sway bar and that would move the inside holes further away from the ends of the rods that drop down from the frame. It looks like those rods are just too short to make the connection to the inside holes on the sway bar. The rods are already located forward of the sway bar and are slanted towards the sway bar to make the connection at the outside holes. I think the connection rods would be an inch or two short of the inside holes. On the rear sway bar the CHF could be done but I would have to lower the sway bar ends in order to connect to the inside holes. It looks like that is certainly doable without causing any additional issues. That's where the nagging design issue thought come into play. Perhaps I am over thinking this but I can't help but wonder why the connections are in the outside holes to being with. I can understand why there are 2 holes in the sway bars, which is probably to make the bars fit different chassis.  If anyone has any design insights I would certainly be interested in seeing them. On another issue I'm looking at rear track bars and I see some connect from the frame to the sway bar bracket that is welded to the axle and some are connected from the frame to bolts on the differential housing. I think the latter would put a lot of stress on those bolts. Does anyone have any thoughts on which is the better approach?
 
WinterAdverse said:
I guess I'm a slow learner. I have been looking at the CHF solutions and can't help but think that there is some reason the design engineers wanted the sway bar connections in the outside hole rather than the inside. I keep thinking if I move the connections to the inside hole I would be defeating some design/safety issue. That being said, the CHF on the front looks like it is a nonstarter with my chassis. In order to move the connections I would have to raise the ends of the sway bar and that would move the inside holes further away from the ends of the rods that drop down from the frame. It looks like those rods are just too short to make the connection to the inside holes on the sway bar. The rods are already located forward of the sway bar and are slanted towards the sway bar to make the connection at the outside holes. I think the connection rods would be an inch or two short of the inside holes. On the rear sway bar the CHF could be done but I would have to lower the sway bar ends in order to connect to the inside holes. It looks like that is certainly doable without causing any additional issues. That's where the nagging design issue thought come into play. Perhaps I am over thinking this but I can't help but wonder why the connections are in the outside holes to being with. I can understand why there are 2 holes in the sway bars, which is probably to make the bars fit different chassis.  If anyone has any design insights I would certainly be interested in seeing them. On another issue I'm looking at rear track bars and I see some connect from the frame to the sway bar bracket that is welded to the axle and some are connected from the frame to bolts on the differential housing. I think the latter would put a lot of stress on those bolts. Does anyone have any thoughts on which is the better approach?

Hear is a design insight. Do the CHF or spend a couple thousand on a stiffer sway bar that does exactly the same thing. I don't know how many thousand have done this with NO PROBLEM.
Pick a track bar no one is having any problems with either attachment method.
Bill


 

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