Gasser Handling - Specific Question

[FloridaRosebud]

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

[mike_brez]

I had a Chevy on the p30 chassis that wandered. New Koni shocks,steer safe,Henderson super steer bell cranks,rear trac bar and coil springs,ipd larger front sway bar with ploy bushings front and rear. Three or four front end alignments a couple sets of tires a few times over the cat scale and guess what it still wandered.
I finally fixed it





I sold that POS and got this DP

[FloridaRosebud]

Cloud Dancer wrote:

FloridaRosebud wrote:

Cloud Dancer wrote:
My F-53 chassis came with anti-roll bars. They were designed as a matched set, and selected to do a good job,... and they did. The front leaf springs were sagging, prematurely. This caused bottoming out onto the rubber stops. It also resulted in some "bump steer". I installed front Firestone airbags to return the ride height to normal, and I added a front panhard link. I also installed wedge shims designed to increase the caster 2 degrees, and added front ballast in order to assure caster authority. Everything worked very well in improving the directional stability. But, I had occasion to drive a large diesel pusher with a Spartan chassis. The rest is history.

I'm trying NOT to drive a DP, as I'm afraid if I do I'll be in debt up to my nose...forever.....;)

Mine came stock with anti-roll bars as well. Rear was about .75" in diameter, and the Helwig is 1-5/8". Made a big difference. The stock front is 1" in diameter, the Hellwig is 1.75". So it stands to reason that the difference in size should help out the front of the MH and we'd be back to a "matched" set, just bigger. My Mechanical Engineer and I discussed the specs of the MH, and he felt like the two biggest issues was the wheelbase was too short for the length, and the MH was not heavy enough for the surface area of the sides and as a result getting pushed around was inevitable.

Al

I screwed up. My Vectra had a wheelbase of 228 inches, giving it a wheelbase-to-overall length ratio of 56%. Yours, with a 208" wheelbase has a ratio of 51%. The rear overhang length of my Vectra was significantly shorter as well. This means that mine had a head start on the chances of having better directional stability. I can now see what drove you to install all the improvements. This also gives me reason to believe that yours might be too light on the front (not enough caster authority) You might want to try a bunch of sandbags up front (just to see what difference it makes).

That might be worth trying on our next trip out. Front axle weighed 6,090lbs with wife and I in the front seat. 7,500lb rating, so there is room for more. Rear weighed 12,890lbs, with a rating of 14,500lbs. We were fully loaded on our way out for 3 weeks. Full tank of fuel and about 50% full water tank.

When we bought the MH I had done zero research on class A's. We had gone out to look at Trailers, and in a few weeks came home with what we have. That said, we love the floorplan and interior, so I don't know that research would have helped much.

Al

[Cloud_Dancer]

FloridaRosebud wrote:

Cloud Dancer wrote:
My F-53 chassis came with anti-roll bars. They were designed as a matched set, and selected to do a good job,... and they did. The front leaf springs were sagging, prematurely. This caused bottoming out onto the rubber stops. It also resulted in some "bump steer". I installed front Firestone airbags to return the ride height to normal, and I added a front panhard link. I also installed wedge shims designed to increase the caster 2 degrees, and added front ballast in order to assure caster authority. Everything worked very well in improving the directional stability. But, I had occasion to drive a large diesel pusher with a Spartan chassis. The rest is history.

I'm trying NOT to drive a DP, as I'm afraid if I do I'll be in debt up to my nose...forever.....;)

Mine came stock with anti-roll bars as well. Rear was about .75" in diameter, and the Helwig is 1-5/8". Made a big difference. The stock front is 1" in diameter, the Hellwig is 1.75". So it stands to reason that the difference in size should help out the front of the MH and we'd be back to a "matched" set, just bigger. My Mechanical Engineer and I discussed the specs of the MH, and he felt like the two biggest issues was the wheelbase was too short for the length, and the MH was not heavy enough for the surface area of the sides and as a result getting pushed around was inevitable.

Al

I screwed up. My Vectra had a wheelbase of 228 inches, giving it a wheelbase-to-overall length ratio of 56%. Yours, with a 208" wheelbase has a ratio of 51%. The rear overhang length of my Vectra was significantly shorter as well. This means that mine had a head start on the chances of having better directional stability. I can now see what drove you to install all the improvements. This also gives me reason to believe that yours might be too light on the front (not enough caster authority) You might want to try a bunch of sandbags up front (just to see what difference it makes).

[FloridaRosebud]

Cloud Dancer wrote:
My F-53 chassis came with anti-roll bars. They were designed as a matched set, and selected to do a good job,... and they did. The front leaf springs were sagging, prematurely. This caused bottoming out onto the rubber stops. It also resulted in some "bump steer". I installed front Firestone airbags to return the ride height to normal, and I added a front panhard link. I also installed wedge shims designed to increase the caster 2 degrees, and added front ballast in order to assure caster authority. Everything worked very well in improving the directional stability. But, I had occasion to drive a large diesel pusher with a Spartan chassis. The rest is history.

I'm trying NOT to drive a DP, as I'm afraid if I do I'll be in debt up to my nose...forever.....;)

Mine came stock with anti-roll bars as well. Rear was about .75" in diameter, and the Helwig is 1-5/8". Made a big difference. The stock front is 1" in diameter, the Hellwig is 1.75". So it stands to reason that the difference in size should help out the front of the MH and we'd be back to a "matched" set, just bigger. My Mechanical Engineer and I discussed the specs of the MH, and he felt like the two biggest issues was the wheelbase was too short for the length, and the MH was not heavy enough for the surface area of the sides and as a result getting pushed around was inevitable.

Al

[Cloud_Dancer]

My F-53 chassis came with anti-roll bars. They were designed as a matched set, and selected to do a good job,... and they did. The front leaf springs were sagging, prematurely. This caused bottoming out onto the rubber stops. It also resulted in some "bump steer". I installed front Firestone airbags to return the ride height to normal, and I added a front panhard link. I also installed wedge shims designed to increase the caster 2 degrees, and added front ballast in order to assure caster authority. Everything worked very well in improving the directional stability. But, I had occasion to drive a large diesel pusher with a Spartan chassis. The rest is history.

[FloridaRosebud]

Cloud Dancer wrote:
"..the dynamics of suspension". That's fine, except, that in order to find the answers to your questions, IMO you need to isolate the components of your goals. Do you want to concentrate on directional stability first, or do you want to improve on "the handling"?
I should add that I actually was very proud of my 33 ft Winnebago Vectra, when I bought it. It too was on a 208" wheelbase F-33 TRUCK chassis. This chassis is what forced me to try again. It had a long enough wheelbase, but it also had several design deficiencies which made it a poor choice for a motorhome IMO. I could write much more on this subject.
What is YOUR interpretation of "good handling".
What is YOUR interpretation of good directional stability.
Why exactly did you choose to add the rear anti-roll bar?
Do you thoroughly understand how and why "caster" works?
You really do not need to answer these questions. I just wanted you to know some of my thoughts.

Very good questions for sure, but I've pretty much gotten close to where I'd like to be, but just wanted to know if anyone has installed an aftermarket front anti-roll bar, and if they have what were the results. I thought it was a simple question, and I figured there are three possible answers; no, yes and no change, and yes with a change. So far no one has answered the question, they just want me to tell them what my goals are and offer up other suggestions (which certainly are always welcome and helpful).

So to your points:

Good Handling - I want the MH to track straight with minimal corrections. The CHF, the steering stabilizer, and proper alignment and lubrication (often overlooked with a kingpin type of steering) took care of that issue.

Stability - I want minimal (within reason) push from trucks and the wind. The rear anti-roll bar fixed 70-80% of those issues. Proper inflation of the airbags helps as well. So my question to the front anti-roll bar fits in this category. Is it worth adding?

Ride - I want a smooth ride. Well, it's an 2006 F-53 chassis. Good luck with that. However, weighing the MH and putting the proper inflation into the tires helped. The shocks are new Bilsteins the previous owner installed. I do not like them as they are too stiff, so sometime in the future as funds allow I'll replace with the adjustable Koni shocks.

Al

[Cloud_Dancer]

"..the dynamics of suspension". That's fine, except, that in order to find the answers to your questions, IMO you need to isolate the components of your goals. Do you want to concentrate on directional stability first, or do you want to improve on "the handling"?
I should add that I actually was very proud of my 33 ft Winnebago Vectra, when I bought it. It too was on a 208" wheelbase F-33 TRUCK chassis. This chassis is what forced me to try again. It had a long enough wheelbase, but it also had several design deficiencies which made it a poor choice for a motorhome IMO. I could write much more on this subject.
What is YOUR interpretation of "good handling".
What is YOUR interpretation of good directional stability.
Why exactly did you choose to add the rear anti-roll bar?
Do you thoroughly understand how and why "caster" works?
You really do not need to answer these questions. I just wanted you to know some of my thoughts.

Correction:
CORRECTION:
The wheelbase on my Vectra was 228 inches. I remembered that on mine the wheelbase-to-overall length was about 56%, giving it better directional stability than the subject motorhome (208" wheelbase with 51% ratio.

[wa8yxm]

Yes Trac Bar and Panhard are the same thing

ANd yes I think we are and that's why I posted about Trac Bars.

True story
Got my rig in 2005.. Jan 2 2006 left Detroit for Las Vegas.. Finaly "Dropped" the 1992 Lumina and parked the MH.. It was a RELIEF to drive the Lumina.

Summer of 2006 I installed a Davis Trac Bar and a Blue-ox Tru Center (Stablizer)

Tuesday before Thanksgiving I went downtown (Detroit. Old St. Mary's Greektown) for the concert (Wayne State University entire school of music. Lovely concert)
THen home and off to Ham Radio Class (I'd tested out that morning.. Passed too. now an Extra Class. all done with tests).

Then headed back to Bento Harbor MI for lunch with my not-so-little brother (He's 6'6.5" tall. but younger than I hence "Not so little).

Then back to Vegas..
Same 1992 Chevy Lumina was .. Hard to drive all of a sudden

Same RV. Same towed. What changed. Trac-bar and stablizer.

[FloridaRosebud]

OK, to be clear, this is what I'm talking about for the front:

https://www.suspensionconnection.com/7217.html

This is what I installed on the rear:

https://www.suspensionconnection.com/7216fv.html

Note they call them "sway bars" when in fact, as some have pointed out, they are truly anti-roll bars. Like Chum Lee, I'm an Engineer and understand the dynamics of suspension, and I have a vehicle guy (Mechanical Engineer) who works for me. He has made the same comments as some of you - that the seller of these items are calling them the wrong thing.

Al

[Cloud_Dancer]

Are we talking about two(2) DIFFERENT types of bars?
What is being called "Trac bar" is really a Panhard link.
What is being called "Sway bar" is really a anti-roll bar.
A panhard link carries a push or pull force. It locates two components laterally. Whereas a anti-roll bar is a torsion spring, similar to a suspension torsion bar.

[wa8yxm]

Sway bars or Trac Bars.. I assume a 2nd one will help.

But one of the issues with LEAF SPRING suspension is side to side "Wag" if the front goes one way and the back the other.. YOu compensate by turning ye old wheel sice you think "Drifting" then they sway and you compensate the other way. and back and forth and back and forth and back and forth and back and forth and back and forth and back and forth and back and forth (Goes on till you park).

Trac bars.. Well one may be enough but 2 STOP THIS DEAD,

[FloridaRosebud]

Chum lee wrote:

FloridaRosebud wrote:


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

OK, you asked for thoughts. Clearly you've changed your suspension, . . . a lot. So, . . . . what's left? Would you consider changing yourself? After everything you've changed, if you are still having 2 or 3 butt-puckering events (your words) each 300 mile driving day, could it be that you are pushing yourself/motorhome too much? You aren't driving a race car on a race track. Just the opposite. As an engineer myself, I can tell you that suspension systems are designed to give the driver appropriate feedback to let them know when they are "pushing it" a little bit too much. When you change the system so that you are driving on the edge without knowing it, don't be surprised when sh*t just "happens" all of a sudden, out of nowhere. That's your design. As always, how you drive is your business and under your control. Not a lecture, . . . . just food for thought, which you asked for.

Chum lee

No worries, you make some good points. After becoming acclimated to driving the MH I found that setting the cruise at 60-62 was where it seemed to track nicely, but Semi's would most of the time move me over a foot or two. After the changes I felt more comfortable going 65-66, but I found that slowing back down to that 60-62 reduced the events down to that 2 or 3. The "edge" seems now to be close to 70, but I certainly don't want to push it there. I'm comfortable where I'm at now, but was wondering if the front mod would rid myself of all of the events at my current speed. That said, I'm sure that there will be times when the s**t happens and no amount of suspension mods will help. In my book that would be called "not paying attention"

Al

[rgatijnet1]

FloridaRosebud wrote:

rgatijnet1 wrote:
Up you air bag pressure to 80 psi and take it for a drive on the highway. This costs nothing and it may be all that you need to do to minimize sway.

I already tried that and it made the MH ride a bit too hard for my wife and I. A friend said I should just buy a DP and be done with it. I told him if he gave me about $150k I'd be happy to do that....he didn't bite...:)

Al

On my coach I had a button on my dash to raise or lower the air pressure. When on a smooth highway, I increased the air pressure to prevent sway, especially on windy days in the Great Plains. On rough roads, where I was going to be going slower to begin with, I lowered the air pressure for a smoother ride. Not that difficult to adjust for the road surface or wind conditions.

[Chum_lee]

FloridaRosebud wrote:


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

OK, you asked for thoughts. Clearly you've changed your suspension, . . . a lot. So, . . . . what's left? Would you consider changing yourself? After everything you've changed, if you are still having 2 or 3 butt-puckering events (your words) each 300 mile driving day, could it be that you are pushing yourself/motorhome too much? You aren't driving a race car on a race track. Just the opposite. As an engineer myself, I can tell you that suspension systems are designed to give the driver appropriate feedback to let them know when they are "pushing it" a little bit too much. When you change the system so that you are driving on the edge without knowing it, don't be surprised when sh*t just "happens" all of a sudden, out of nowhere. That's your design. As always, how you drive is your business and under your control. Not a lecture, . . . . just food for thought, which you asked for.

Chum lee

[FloridaRosebud]

rgatijnet1 wrote:
Up you air bag pressure to 80 psi and take it for a drive on the highway. This costs nothing and it may be all that you need to do to minimize sway.

I already tried that and it made the MH ride a bit too hard for my wife and I. A friend said I should just buy a DP and be done with it. I told him if he gave me about $150k I'd be happy to do that....he didn't bite...:)

Al