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Gasser Handling - Specific Question

FloridaRosebud
Explorer
Explorer
I have a specific question regarding improving the handling on my 33' National SeaBreeze. I realize there have been many threads on this topic (I've participated in some of them) but I've not seen this discussed. The MH is 33', 208" wheelbase, F-53 chassis. I've done the CHF, have a steering stabilizer, and added a Hellwig rear anti-sway bar. Firestone airbags as well, and run the "correct" tire pressures based on the MH weight (actually weighed). All this improved the handling greatly, and pretty much eliminated the wandering.

So the question - is there any additional improvement to be had adding the Hellwig front anti-sway bar, or have I reached the point of diminishing returns? I would say at this point I've gone from many butt-puckering moments to maybe 2 or 3 over a 300 mile day, as most larger trucks no longer push me around like before. To put a number on it I'd say everything has improved 70-80%. As an aside, I've found that running the driver side air bags at 30psi, and the passenger side at 45-50psi also helped tame the "push" and improved stability.

Thoughts?

Al
42 REPLIES 42

FloridaRosebud
Explorer
Explorer
UPDATE - first the refresher - The MH is 33', 208" wheelbase, F-53 chassis. 2006 National SeaBreeze LX. I've now done the CHF, have a steering stabilizer, a Hellwig rear anti-sway bar, rear trac bar, and poly bushings on the original Ford anti-sway bars, front and rear. Firestone airbags as well, and run the "correct" tire pressures based on the MH weight (actually weighed). Toe-in is slightly positive (in). The differences since the last post are the rear trac bar and the toe in.

So we have gone 800 miles on this trip now, and the handling issues have pretty much been solved. Semis are a non-issue, wondering is pretty much gone, and no more butt-puckering experiences. Crosswinds to 10-12mph are non-issues as well. While I still pretty much set the cruise on 60-62, on flat roads I've gone to 65 and felt comfortable. Thanks to everyone for their help and input. I just thought I would close the loop on this thread.

Safe travels everyone.

Al

dodge_guy
Explorer
Explorer
Thanks for the update! glad everything is working out. From my research the tire pressure makes a huge difference!
Wife Kim
Son Brandon 17yrs
Daughter Marissa 16yrs
Dog Bailey

12 Forest River Georgetown 350TS Hellwig sway bars, BlueOx TrueCenter stabilizer

13 Ford Explorer Roadmaster Stowmaster 5000, VIP Tow>
A bad day camping is
better than a good day at work!

FloridaRosebud
Explorer
Explorer
UPDATE - just drove 625 miles over 2 days to NC from Fl for a month. Added the Roadmaster front steering stabilizer (true center) and adjusted the air bags on the passenger side to 65 PSI since the last post. I believe we are "there". MH handled great, and was not pushed around by the semi trucks. The only "butt-puckering" moment was my fault, as I let the MH get up over 70mph going down a big incline, and the MH let me know. I was able to set the cruise on 65, 3 mph higher than before, and felt very comfortable driving. So my thoughts:

1. The modifications I've done have helped tremendously, and were the right thing to do.
2. The modifications don't really fix the problem, (too short a wheelbase, too light a coach for it's size) but they make it livable.
3. Cross winds of more than 15 mph are going to give me issues no matter what modifications I make.
4. It's now up to me to drive the Mh correctly, IOW keep the speed to 62-65mph and no more.

So thanks again to everyone who made suggestions and helped out. Now it's time for an adult beverage.....

Al

FloridaRosebud
Explorer
Explorer
A quick update - just got back from Perry and the MH handled the best it ever has since I've owned it. The only two butt-puckering experiences were twice when I "rutted" and went into the rumble strips. MH recovered nicely and got back in the lane.

So what did I do - first I did not order the front bar, and decided to first go back to my frame and alignment shop for them to go through it again. They did and they added a bit of caster. While the MH was on their rig it was, of course, perfectly level (well, the frame was) so we took that opportunity to figure out how much air was necessary in each airbag to get the MH level. The results were surprising. With 30psi on the driver's side, we needed 65psi on the passenger side. The shop checked all the suspension components and everything was good. So I plan on having the MH weighed at each tire to see my true weight distribution. (when full of course). My company has a portable machine we use for accident reconstruction, so I'll use that.

So with the new air pressures and caster the handling was much improved. I have decided to remove the current steering stabilizer, which is not a return to center (RTC) unit, and replace it with one that is (A Roadmaster). I think this will be a bigger bang for the buck, improve safety in the event of a front tire blowout, and it might have eliminated the "rutting" I mentioned at the top. This last trip I was able to drive the MH longer without a break, and did not feel wiped when I got home.

Thanks to all for their thoughts and advice.

Al

FloridaRosebud
Explorer
Explorer
Cloud Dancer wrote:
Rosebud, yes I understand that you just want to know about the results if you add a stiffer anti-roll bar to the front suspension. I did NOT answer because IT'S COMPLICATED (difficult to conceptionalize). Whenever I hear the word "handling" applied to this subject, I start questioning how many of us here understand the "science" of understeer and oversteer. Specifically, whether you understand WHY, generally speaking, increasing the roll stiffness in the rear suspension also increases the oversteer character, AND if you increase the roll stiffnes in the front it will increase the understeer character?
At this point, in explaining the science of it, most RVers will say, what the he!! does this have to do with it! It has a LOT to do with it!
In fact, this subject is ssooo broad, this forum can not do it justice.
Perhaps I should've just said to go ahead and install the stiffer FRONT anti-roll bar. THEN, install a front panhard link, and add caster and front ballast.


I understand the principle of which you speak, and my Mechanical Engineer and Hellwig both said I should install both the front and back as they are a matched set and offset the oversteer/understeer issue. The issue with suspension is everything affects everything. You are absolutely correct. I just wanted to know if anyone has done the install of the front bar itself (maybe after other mods) and what, if any difference did they find. From the lack of responses I guess the answer is a big no.

So I plan on ordering the front soon and installing it.

Al

Cloud_Dancer
Explorer II
Explorer II
Rosebud, yes I understand that you just want to know about the results if you add a stiffer anti-roll bar to the front suspension. I did NOT answer because IT'S COMPLICATED (difficult to conceptionalize). Whenever I hear the word "handling" applied to this subject, I start questioning how many of us here understand the "science" of understeer and oversteer. Specifically, whether you understand WHY, generally speaking, increasing the roll stiffness in the rear suspension also increases the oversteer character, AND if you increase the roll stiffnes in the front it will increase the understeer character?
At this point, in explaining the science of it, most RVers will say, what the he!! does this have to do with it! It has a LOT to do with it!
In fact, this subject is ssooo broad, this forum can not do it justice.
Perhaps I should've just said to go ahead and install the stiffer FRONT anti-roll bar. THEN, install a front panhard link, and add caster and front ballast.
Willie & Betty Sue
Miko & Sparky
2003 41 ft Dutch Star Diesel Pusher/Spartan
Floorplan 4010
Blazer toad & Ranger bassboat

hussbuss
Explorer
Explorer
Don't want to start a big discussion on this, but I am a firm believer of the AIR TABS. Have them on my 37 ft. Travel trailer. Used to watch for semis coming up all the time, now don't know they are there until I see them along side of me. The Air Tabs create a vortex that pushes the bow wave back at the passing semi before it hits you. My brother also has them on his new gasser motor home and loves them. Best $220.00 We ever spent.

wa8yxm
Explorer III
Explorer III
I have thought of that but.. Well not yet... I could convert my "Thumb button" to a foot button by simply making a bracket.

I do not use it often.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

mike_brez
Explorer
Explorer
I use a foot operated switch for my blue ox tru center. The one with yellow wires.



1998 36 foot Country Coach Magna #5499 Single slide
Gillig chassis with a series 40
02 Ford F250 7.3 with a few mods
2015 Wrangler JKU

wa8yxm
Explorer III
Explorer III
Re Stablizer. Mine is a Blue-Ox True Center Updated version with time out timer. and yes it is properly installed I have verified installation.

THE BLUE OX.. and optionally the Safe-T-Steer (it's aon option on the STS) have a feature I very much wanted.. A BUTTON. in my case it's next to me on the 2-way radio bar (Explain down post) and I push it it "Unlocks" the device so I can re-center.. If I'm dealing with say a 30 MPH cross wind or a HIgh Dome roadway I can adjust for it.. Then re-center back to normal later.

The radio bar.. A 2x4 or 2x6.. Forget which. Tapered a bit on one edge. Stained and polished and bolted to studs in teh side wall. I then mount 3 different 2 way radios on it. 2 CB's (one on 13 on on 19) and a 2mtr/70CM ham rig (Currently an ICOM ID-5100 but it is not yet mounted Don't have the right bolts).

That way i do not need to be careful about hitting studs with the mounting brackets. Kind of a horizontal stud.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

mtofell1
Explorer
Explorer
What kind of steering stabilizer are you running and how confident are you that it is installed perfectly? Many/most people report greatly reduced or total elimination of the things you are describing with theirs when properly installed.

cwit
Explorer
Explorer
I put n both track bars best mprovement ever. I can tell you don’t want to here this but it is true. I made my own for under 75$ for both. We don’t have any problem with tractor trailers at all and travel 3,000 interstate miles every year.

Big_Katuna
Explorer II
Explorer II
Others have said increasing toe in past spec helps. Most tires age out anyways.

When I go from our DP to gas next year a Trac bar will be the first thing I do.

My friend who has had several F53s relates it’s a big improvement.
My Kharma ran over my Dogma.

jharrell
Explorer
Explorer
You have already done the CHF which increases the stiffness of the sway bar by reducing leverage. Replacing that with a thicker sway bar may or may not improve handling.

Two things, first the stiffness of the new thicker sway bar might not be any more than the stock one with CHF, but should be easy to figure it out as its just some math and there are online calculators.

Second stiffer sway bars are a tradeoff as many suspension changes are. As stiffness goes up roll is reduced but so is harshness as now the sway bar is resisting axle articulation more. If solving the problem where just a matter of adding more stiffness we could just have an untwistable sway bar in there or eliminate springs all together. You would have zero roll and and be nice on a perfectly smooth road but horrible in the real world.

I did 3 things that all helps equally in my opinion.

1. Rear track bar
2. CHF
3. Increased toe in

Both CHF and Toe where free and relatively easy to do myself while the trackbar has a cost and was more complicated.

These mods work together and do completely different things.

Surprisingly the toe from the factory was 3/32" out, which while technically in spec you never want toe out, it causes wander and rut following. I did 3/32" in which is at the other end of the spec and made a noticeable difference as big as the CHF. Many even recommend 1/8" toe in but again this is a trade-off, the more toe in the tighter it tracks but the more tire wear you get.

IMO the F53 chassis needs front and rear track bars, they started doing front in 2006 or 2008 I believe and still does not have a stock rear. It also needs stiffer sway bars which can be accomplished with the CHF or new ones and of course proper alignment, toe being easy to do yourself, caster is important as well but requires shims between leaf and axle.

BTW here is the sway bar formula, the CHF reduces A and C while an new thicker sway bar changes 😧

2016 Winnebago Vista 31be - Blue Ox Rear Track Bar - Centramatic Wheel balancers
2016 Jeep Wrangler Unlimited Rubicon Toad - Readybrute Elite Towbar