Road handling and stability

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Cuervo1

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Has anyone installed ROADMASTER anti-sway bars, front or rear, and did road handling improve?
I am considering having them installed after a white knuckle, come to Jesus experience in 50 mph crosswinds.
 

billwild

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First off check your tire pressures. Your pressures may be too high, causing the coach to wander easily. Lots of people do not pressure up to the maximum and find their motor homes handle better.


Bill
 

Gary RV_Wizard

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I've not done that, but am confident it would help some in severe crosswinds.  However, it's still likely to be "white-knuckle".  A slab-sided vehicle in 50 mph winds is no picnic at best, and the only sensible thing would be to get off the road.

How is the handling in light or no winds? 
 

RVRAC

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I installed Hellwigs and Roadmaster steering stabilizer.  Big difference.
 

kdbgoat

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I'm with Gary, there's no way I would be running down the road in 50 mph cross winds. I don't care what you do to a class C or any other RV, 50 mph cross winds will still give you white knuckles.
 

Larry N.

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We had similar winds, once, in a 34' Bounder, and had to slow to 30 mph (on the Interstate), then stopped at the first place (a truck stop) where we could spend the night until the winds subsided enough for us to proceed. Tire pressure (especially on the front) is crucial in handling, and as Gary said those slab sided units with a long rear overhang are a nightmare in that kind of wind, regardless of how well it does otherwise.

There was a BIG improvement when I replaced the Bounder with a 45' Beaver, as it handled that kind of wind fairly well (still a bit of a handful, though, in gusts, but no longer scary). Of course the Beaver was much heavier (over 42,000 lbs empty), sat lower to the ground and had a much shorter rear overhang.
 

Harvard

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billwild said:
First off check your tire pressures. Your pressures may be too high, causing the coach to wander easily. Lots of people do not pressure up to the maximum and find their motor homes handle better.


Bill

Lowering the tire pressure will increase the caster trail as will increasing the caster angle to the upper end of the specified caster range.
The key word here is "wander" as in:

POPULAR MECHANICS MAY 1973:
START QUOTE:
If too little caster exists, the car will wander and weave,
thus necessitating constant corrections in steering.
END QUOTE:

 

Cuervo1

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Thanks for the advice. I had all new tires installed and an alignment prior to trip, so caster was fine. I was however, running max tire pressure ,(85 psi). I will try reducing a little. Still think I will try the Roadmaster stabilizer at least on rear. Will advise if it makes any improvement. It will be awhile though,because I'm wearing a knee immobilizer due to knee surgery to repair a total quadriceps tear and tendon rupture which happend on that windy trip.I

I am enjoying forum very much while I am laid up.
 

Gary RV_Wizard

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It's risky to experimentally reduce tire pressures. Either use the factory recommended pressure from the placard by the driver seat, or use axle or individual wheel weights and a tire load/inflation table to choose an optimal pressure for the actual weight load.  Just experimenting may yield a pressure that is too low to safely carry the load and cause internal damage to the tire, but you may not realize it until a tire blows out unexpectedly.

There have been numerous topics here in the past concerning proper tire pressure - you may want to look them up (Search)
 

kdbgoat

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Cuervo1 said:
Thanks for the advice. I had all new tires installed and an alignment prior to trip, so caster was fine. I was however, running max tire pressure ,(85 psi). I will try reducing a little. Still think I will try the Roadmaster stabilizer at least on rear. Will advise if it makes any improvement. It will be awhile though,because I'm wearing a knee immobilizer due to knee surgery to repair a total quadriceps tear and tendon rupture which happend on that windy trip.I

I am enjoying forum very much while I am laid up.

The alignment issues Harvard is talking about is even though the caster may be in spec, doesn't necessarily mean it's optimum. The E-450 should have about 5 degrees of caster to handle properly. Do an internet search on "E-450  caster" and check it out yourself. I have yet to figure out why folks start throwing money and parts at something before doing the basics first. As far as air pressure in the tires, by the time a 31' RV built on an E-450 chassis is loaded up for use, you will probably be running at max pressure according to the placard, but it certainly doesn't hurt to check. If possible, do a four wheel weigh. Being overloaded on a corner is easily done, and can effect handling and safety. I loaded mine heavier on the front right when I first got it because I figured the generator was mounted on the front left. When I got it on the scales at work, I was pretty surprised. I had to take the heavy tools etc. from the right front locker and move them to the left rear area. No matter what you do though, with 50 mph crosswinds, you need to get off the road.
 

Harvard

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Ford ships the E Series cut aways with +3 to +4 degrees of caster which is OK for city driving. You want to have +5 to +6 degrees for highway speeds.

As far as E350/E450 alignments go, 2kGorgieBoy says it best:

http://www.rvforum.net/SMF_forum/index.php/topic,112427.30.html


Reply Post by 2kGeorgieBoy

Re: Wandering at highway speeds
Reply #36 on: March 14, 2018, 09:07:02 PM


START QUOTE:
Jeff..Although we have a 2000 Georgie Boy 31' Maverick "C" on  a Ford E450 chassis, I can fully agree on the caster effects, at least for us.  When we got the unit in  Jan 2014, the dealer had us take into a  truck shop for an alignment. It turned out OK....A trip to Moab shortly there after brought out the problems. I then started reading the threads and comments here about the caster settings....esp., from Harvard. I checked the data from the first alignment and found that it was set at about 3 1/2 degrees positive...about in the middle of Ford's recommended range. Shortly before a cross country trip to Maryland in fall of 2016, I returned to the shop where the first alignment was done. I talked to the service manager and he knew of the problems with the E450's and was happy to increase the caster as I asked. The alignment tech was also familiar with it and ended up with settings close to 5.5 degrees positive. WHAT A DIFFERENCE! The unit tracked straight down the road, passing semis no longer caused a white knuckle hold on the wheel, and overall it was just a lot more enjoyable. It did however increase steering effort a little but not anything to worry about.  But, be sure that the shop you go to is willing to "think outside of the box". Our first alignment was "plain vanilla", right in the middle like it was always done. Second time out, they were very willing to increase settings beyond what normally would be done, and still stay with in Ford's guidelines (0-7 degrees, I believe). I realize that our E450 chassis is an entirely different animal than yours, but I was trying to add support to the caster increase thinking and how it helped us......if you go down that road.
END QUOTE:
 

Cuervo1

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Thanks again for all of your expertise. I checked my alignment printout,caster set at  Left+6.3 and Right+5.7 Which is the same as it was before alignment. The only adjustment that he changed was toe, which was way off. I'm now looking at Hellwig, anti sway bars. They are cheaper than Roadmaster. RVRAC posted he has them and made a big difference
 

Harvard

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Cuervo1 said:
Thanks again for all of your expertise. I checked my alignment printout,caster set at  Left+6.3 and Right+5.7 Which is the same as it was before alignment. The only adjustment that he changed was toe, which was way off. I'm now looking at Hellwig, anti sway bars. They are cheaper than Roadmaster. RVRAC posted he has them and made a big difference

Your cross caster is 6.3 - 5.7 = +0.6

Cross caster should always be 0.0 or NEGATIVE if you drive on the right hand side of the road crown.
Your unit will pull to the right on the right hand side of the road crown.
 

Cuervo1

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Harvard.
You seem to be the most educated person around on the subject of caster.Should this be corrected, or is it a condition I should live with? I don't think the place where I had the alignment  done will re do it. I had a bit of a pissing contest with them when they tried charge me $200. after being quoted $ 125. when I made the appointment. We settled on $ 175.
 

Harvard

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Cuervo1 said:
Harvard.
You seem to be the most educated person around on the subject of caster.Should this be corrected, or is it a condition I should live with? I don't think the place where I had the alignment  done will re do it. I had a bit of a pissing contest with them when they tried charge me $200. after being quoted $ 125. when I made the appointment. We settled on $ 175.

Yes it should be corrected BUT make sure you did not mix up the LH and RH on the report.

Cross Caster = LH - RH and should be a NEGATIVE number ideally in the order of -0.2 to -0.5 for driving on the right hand side of the road crown.

If your report gives the cross caster it might also spec the acceptable cross caster range. If the cross caster is clearly printed to be out of range I would take it back.

This alignment shop has made a good income from "tweak the toe and its good to go" business.
 

Old_Crow

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I was taught that the vehicle will pull to the side with the least positive castor, so with the left at 6.3 and the right at 5.7, the thing would drift to the right on a straight level road.  Factor in the road crown and the drift becomes a pull.
If you could find a shop that would pretty much reverse those readings right to left, the coach ought to track like an arrow.

I, personally, favor a slight drift to the right and tend to set my vehicles with very little cross castor.  Less chance of drifting into the opposite lane with a moment of inattention.  Stupid?  Maybe, probably more silly than anything.  Another result of over thinking a simple thing, no doubt.
 

Harvard

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Old_Crow said:
... I, personally, favor a slight drift to the right and tend to set my vehicles with very little cross castor. ...

That too was my choice.
 

Cuervo1

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Harvard
Can this be corrected with the Ingalls 5400? Would it be possible to reduce the Left setting a little? From what I gather, the Right is good at 5.7, if I understand correctly.My alignment printout does not indicate Cross Caster,it does indicate Steer Ahead,which is +0.05 and Total Toe which is -0.02.
 

Harvard

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Cuervo1 said:
Harvard
Can this be corrected with the Ingalls 5400? Would it be possible to reduce the Left setting a little? From what I gather, the Right is good at 5.7, if I understand correctly.My alignment printout does not indicate Cross Caster,it does indicate Steer Ahead,which is +0.05 and Total Toe which is -0.02.

Yes, you can resolve this cross caster issue with the Ingalls 594s by reducing the LH caster from +6.3 to +5.5 (RH is +5.7) and you should be good to go.

If you are going to DIY you need to remove the LH wheel to reduce the weight issues involved with turning the 594 sleeves. Play safe.
 
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