Need help for continuing to modify Suspension

[JDCrow]

3 hours ago, Cubflyer said:

I always fill my tires to cold pressures when my tires are cold, usually in the morning so sun has not been shining on them.  Last summer I started my trip at about 200' above sea level.... traveled to Denver... about 5000' above sea level, on to SLC, again even higher..... and also the temps were warmer.  I monitored my tire pressures with that cheapo TPS and never added or removed any air.... I did use a mechanical TP gauge (dial type) once on the 6 week trip, just to confirm my cheapo TPS... (the TPS is not super accurate, but is a good 'reference' and does show temperatures too, gives audio warnings for high or low pressure and at least high temps...)  My tires have never 'gained' pressure except for by the heat generated while going down the road...... at least not enough for me to notice... I'm not 'super sensitive' .... more of a horse shoe and hand grenades when it comes to tire pressure.

Ok, I don’t think they cooled down from the previous day. I had the new rears put on today and should be good to go in the morn. I just finished the sway bar, and it went well and my angles look pretty good. 2 bolts were 1/2” to long and had to run to tractor supply. They hit the axle as I was tightening them. Safety Steering back in as well

[Cubflyer]

JD,

Yes the angles do look pretty good, almost like your sway bar 'arms' are a little longer than the arms on the one I installed, I'll have to look, but I do not think my links are as close to the H frame as yours.... if the bolts that were too long were the fwd bushing bolts, I think I put mine in with the heads on the axle side (put in place before I mounted the thick plate), but again, I'll have to look.  Same deal on the upper mounts on the link mounting (fwd) end.. head down, nut on top.....

Hope you notice an improvement, I believe you will... look forward to your report.

Ken

oh, and did it seem like you were bench pressing that sway bar when you put it up in place?  

Edited October 27, 2021 by Cubflyer
clarify

[JDCrow]

Ken,

Yeah flipping the bolts would have been the ticket. I just have a thing for bolts on bottom. Don’t know why. I did flip the long bolt that went in the arm side of the frame hanger mounts. Though the end didn’t touch or mess up the arm swinging, I just wanted more space. 
 

Heading out 12ish for Grand Canyon for a few days. 5 hrs or so of driving to see how she feels 

Here’s a Van or Bob question:

This week been trying to get a fab guy to come and build a frame to move the front watts from behind the front axle to on front of it. The idea expressed was needing 2 things: 1) get it away from panhard rod as much as possible, and 2) tie the front of the H frame to the solid center to get it stabilized 

As I’m under the coach today, I’m looking it and thinking about the issues I’m having, then I wonder, is there anything wrong with having 2 Watts set ups on the front? Other than a dent in my wallet? 
 

Also as I’m looking at the rear when the tires are off, it looks like the rear watts will be right next to the panhard rod as well. 

[vanwill52]

12 hours ago, JDCrow said:

Ken,

Yeah flipping the bolts would have been the ticket. I just have a thing for bolts on bottom. Don’t know why. I did flip the long bolt that went in the arm side of the frame hanger mounts. Though the end didn’t touch or mess up the arm swinging, I just wanted more space. 
 

Heading out 12ish for Grand Canyon for a few days. 5 hrs or so of driving to see how she feels 

Here’s a Van or Bob question:

This week been trying to get a fab guy to come and build a frame to move the front watts from behind the front axle to on front of it. The idea expressed was needing 2 things: 1) get it away from panhard rod as much as possible, and 2) tie the front of the H frame to the solid center to get it stabilized 

As I’m under the coach today, I’m looking it and thinking about the issues I’m having, then I wonder, is there anything wrong with having 2 Watts set ups on the front? Other than a dent in my wallet? 
 

Also as I’m looking at the rear when the tires are off, it looks like the rear watts will be right next to the panhard rod as well. 

The Panhard rod and the Watts links do not have coincident travel arcs.  (Image two hinges with the hinge pins not in line with each other--one hinge "fights" the other.) The Panhard rod, when the H-frame moves up and down, causes a slight sideways motion of the H-frame.  That is the reason it is placed as nearly horizontal at normal travel height--to minimize that sideways motion.  The Watts link tries to keep the motion of the H-frame PERFECTLY vertical.  So, the Watts link and Panhard rod are "fighting" one another.  As it applies to curing wandering, that conflict is definitely NOT a problem.  The farther the Panhard rod is from the Watts link, the less the conflict.  However, if you were to couple TWO Watts links to the H-frame (one toward the front, one toward the rear) that conflict of motion between the Panhard rod and two Watts links would develop some huge forces.  Something will probably break.  DON'T DO IT.

OTOH, if Watts links were rugged enough (ours are NOT), you could eliminate the Panhard rod altogether and depend on the two Watts links (one front of H-frame, one rear of H-frame) to thoroughly stabilize the H-frame.  Similarly, TWO Panhard rods (with NO Watts links) would accomplish stabilizing the H-frame.  Had the original Chrysler design incorporated those two Panhard rods, "wandering" would never have been a topic of conversation.

[JDCrow]

9 minutes ago, vanwill52 said:

The Panhard rod and the Watts links do not have coincident travel arcs.  (Image two hinges with the hinge pins not in line with each other--one hinge "fights" the other.) The Panhard rod, when the H-frame moves up and down, causes a slight sideways motion of the H-frame.  That is the reason it is placed as nearly horizontal at normal travel height--to minimize that sideways motion.  The Watts link tries to keep the motion of the H-frame PERFECTLY vertical.  So, the Watts link and Panhard rod are "fighting" one another.  As it applies to curing wandering, that conflict is definitely NOT a problem.  The farther the Panhard rod is from the Watts link, the less the conflict.  However, if you were to couple TWO Watts links to the H-frame (one toward the front, one toward the rear) that conflict of motion between the Panhard rod and two Watts links would develop some huge forces.  Something will probably break.  DON'T DO IT.

OTOH, if Watts links were rugged enough (ours are NOT), you could eliminate the Panhard rod altogether and depend on the two Watts links (one front of H-frame, one rear of H-frame) to thoroughly stabilize the H-frame.  Similarly, TWO Panhard rods (with NO Watts links) would accomplish stabilizing the H-frame.  Had the original Chrysler design incorporated those two Panhard rods, "wandering" would never have been a topic of conversation.

Thanks for the lesson. I’ll stick with trying to move the Watts when I get home. 
 

To install another panhard seems daunting, unless it was adjustable. Aligning the H frame to the frame and to go straight down the road. Maybe I’m over thinking it as it’s not my line of work. 

[dl_racing427]

5 hours ago, JDCrow said:

Thanks for the lesson. I’ll stick with trying to move the Watts when I get home. 
 

To install another panhard seems daunting, unless it was adjustable. Aligning the H frame to the frame and to go straight down the road. Maybe I’m over thinking it as it’s not my line of work. 

I think finding room for another Panhard rod would be difficult.
Both rods would need to have similarly located mounting points at each end, as well as be the same length for them to work together properly.
That would be the ultimate in simplicity, strength and stability though.

[Ivylog]

I still put in 12+ hour days to-from the West…impossible to do if the rig didn’t handle well. A tag axle rig doesn’t porpoise as much as a non tag which may explain the better handling. The front suspension is the same on tag and non tag rigs…my 04 Dynasty and 08 Navigator do not wander down the road., I love driving them for over 100K miles.
 

Guess I’m still confused. If the amount the pan hard bar moves the H frame side to side results in wandering, what about the changing steering input from the tie rod when the axle moves up/down??? The side to side movement is on a 200+” arm (rigs wheelbase) while the tie rod moves a 12” arm. Yes, the tie rod is longer than the p hard rod but it still affects the steering but not adversely???

Has anyone put a Watts link on a S-10’s front axle? I would love to drive it to see what I’m missing.

[Dr4Film]

1 hour ago, Ivylog said:

Has anyone put a Watts link on a S-10’s front axle? I would love to drive it to see what I’m missing.

I believe Dave Pratt had one installed on his 2005 Exec before he sold it. I think Mike H. owns it now.

[vanwill52]

2 hours ago, Ivylog said:

I still put in 12+ hour days to-from the West…impossible to do if the rig didn’t handle well. A tag axle rig doesn’t porpoise as much as a non tag which may explain the better handling. The front suspension is the same on tag and non tag rigs…my 04 Dynasty and 08 Navigator do not wander down the road., I love driving them for over 100K miles.
 

Guess I’m still confused. If the amount the pan hard bar moves the H frame side to side results in wandering, what about the changing steering input from the tie rod when the axle moves up/down??? The side to side movement is on a 200+” arm (rigs wheelbase) while the tie rod moves a 12” arm. Yes, the tie rod is longer than the p hard rod but it still affects the steering but not adversely???

Has anyone put a Watts link on a S-10’s front axle? I would love to drive it to see what I’m missing.

Tag axle coaches wander less because there are TWO fixed axles.  It is simply harder to cause the coach to change direction.  That is why you are advised to raise the tag when sharp turns are required.  The lack (or an extreme amount) of  "porpoising" has nothing to do with the wandering.

"If the amount the pan hard bar moves the H frame side to side results in wandering..."  It does not.  The amount the Panhard rod moves the H-frame side-to-side is negligible when traveling down an straight highway. It amounts to very little side-to-side movement even during its full range of travel. The wandering is due to the H-frame "squirming" under the coach and changing the direction of the wheels.  Prevent the H-frame from "squirming and twisting" under the coach, and wandering ceases.

As an illustration, imagine a vertical shaft was welded to the  H-frame and extended through your floor, where a steering wheel was mounted to it.   Have someone twist that steering wheel back and forth while you are driving.  The H-frame will twist with it, changing the direction the wheels are pointing.  And, of course, your coach will go where its wheels are pointed.

[JDCrow]

Just rolled into trailer village at the Grand Canyon. 
 

I had to ditch the Truck and have my wife follow me. Really hunting the road left and right. After I took truck off, it was better, still not solid, but better it took less effort to keep it between the lines. 
 

I guess I’m going on I have the rear buttoned up with a watts. She’s squirrelly back there.  The truck on must sway what’s already a unsteady set up. There’s a Speedco on the freeway and going to call Tomorrow to see about an alignment and ride height adjustment for the drive home.

The sway bar did what it’s supposed to, body roll is way minimal now. And porpoising is diminished as well. I’ll most likely spring for the rear sway bar as well. Not sure with the age if the air bags if I shouldn’t just put them on the list as well. If they spongy I reckon it’s contributing to the rear sliding around. Really hated leaving 80 degree days 

[vanwill52]

3 hours ago, Ivylog said:

I still put in 12+ hour days to-from the West…impossible to do if the rig didn’t handle well. A tag axle rig doesn’t porpoise as much as a non tag which may explain the better handling. The front suspension is the same on tag and non tag rigs…my 04 Dynasty and 08 Navigator do not wander down the road., I love driving them for over 100K miles.
 

Guess I’m still confused. If the amount the pan hard bar moves the H frame side to side results in wandering, what about the changing steering input from the tie rod when the axle moves up/down??? The side to side movement is on a 200+” arm (rigs wheelbase) while the tie rod moves a 12” arm. Yes, the tie rod is longer than the p hard rod but it still affects the steering but not adversely???

Has anyone put a Watts link on a S-10’s front axle? I would love to drive it to see what I’m missing.

Tag axle coaches wander less because there are TWO fixed axles.  It is simply harder to cause the coach to change direction.  That is why you are advised to raise the tag when sharp turns are required.  The lack (or an extreme amount) of  "porpoising" has nothing to do with the wandering.

"If the amount the pan hard bar moves the H frame side to side results in wandering..."  It does not.  The amount the Panhard rod moves the H-frame side-to-side is negligible when traveling down an straight highway. It amounts to very little side-to-side movement even during its full range of travel. The wandering is due to the H-frame "squirming" under the coach and changing the direction of the wheels.  Prevent the H-frame from "squirming and twisting" under the coach, and wandering ceases.

As an illustration, imagine a vertical shaft was welded to the  H-frame and extended through your floor, where a steering wheel was mounted to it.   Have someone twist that steering wheel back and forth while you are driving.  The H-frame will twist with it, changing the direction the wheels are pointing.  And, of course, your coach will go where its wheels are pointed.

[Ivylog]

Van, thanks for taking the time to explain BUT there are 4 (guess they are P H Bars), 2 on each side from beside the frame to the H frame that keeps the H frame from twisting in your shaft and wheel example???

Guess my question is: do the 10 bushings in the 5 P H Bars wear over time so the H frame can twist… does the handling start out OK and gets worse as you put miles on the rig?

[JDCrow]

6 hours ago, Ivylog said:

Van, thanks for taking the time to explain BUT there are 4 (guess they are P H Bars), 2 on each side from beside the frame to the H frame that keeps the H frame from twisting in your shaft and wheel example???

Guess my question is: do the 10 bushings in the 5 P H Bars wear over time so the H frame can twist… does the handling start out OK and gets worse as you put miles on the rig?

Radius arms, alignment arms. Keeps the axle from moving forward/backwards in the range of motion up/down. 
 

Ford/Ram use a similar set up for their front axles. 2 radius arms and  1 pan hard rod/arm. Biggest differences, 2 points of contact axle to frame (coil) and that distance is straight up, not 5-6 feet length. 
 

I’ve wondered about coils or timberen taking the place of the air bags on the Roadmaster 

[Ivylog]

I don’t see how a coil spring does anything more than support weight in a linear way. If I had coil springs on the back of my rig, the hitch would be dragging the ground in the slightest dip.

[vanwill52]

6 hours ago, Ivylog said:

Van, thanks for taking the time to explain BUT there are 4 (guess they are P H Bars), 2 on each side from beside the frame to the H frame that keeps the H frame from twisting in your shaft and wheel example???

Guess my question is: do the 10 bushings in the 5 P H Bars wear over time so the H frame can twist… does the handling start out OK and gets worse as you put miles on the rig?

The Panhard rod is the single 2" square tube that runs crossways of the frame. One end is connected to the coach frame, the other to the H-frame.  The other four 2" square bars running front-to-rear (two on each side) are the trailing arms.  They locate the H-frame (and therefore the axle) front-to-rear, but are long and spindly.  If there were NO Panhard rod, the H-frame would wallow INCHES side-to-side.  The SINGLE Panhard rod stops that extreme movement, but does not stop the H-frame from twisting along a vertical axis with its pivot point being the end connection of the Panhard rod.

Bushing wear is only a problem on approximately 1999 and older coaches.  There are much stiffer bushings available from ATRO and I have installed several sets.  On 1999 and older coaches, they make a very large difference.  On coaches with the later design bushings, the difference is minimal.

In short, the wandering is from a design defect in the Roadmaster chassis, not from wear.  They wandered when brand new.  The chassis needed TWO Panhard rods, or ONE with a very long engagement distance at each end--instead of one bushing in each end, it needed two in each end, housed in a tube (I'm guessing) about 6-8" long.

[vanwill52]

JD, you said you had rear X-braces.  Please take a few pix and post.

[JDCrow]

1 hour ago, Ivylog said:

I don’t see how a coil spring does anything more than support weight in a linear way. If I had coil springs on the back of my rig, the hitch would be dragging the ground in the slightest dip.

Depends on the rate of the spring. 

11 minutes ago, vanwill52 said:

JD, you said you had rear X-braces.  Please take a few pix and post.

Yep was just outside on my way to the store 

[waterskier_1]

On 10/26/2021 at 11:07 AM, JDCrow said:

 

Question on air pressure:

I always check air pressure before I leave, every time. 
 

I run 95 front and 105 rear based on the weights from the scales. 
When I left Yuma a week ago, it was hit outside and all the tires were at 110 psi, so o dropped them to my normal “cold” pressure. Was this a mistake? It’s the first time for me in the heat with tires and got to thinking maybe my wandering was amplified with my air pressure. Any advise on what I should have done?

You should never re-adjust tire pressure based on outside temp changes unless you have a valid reason to suspect they were not adjusted correctly originally.  This could occur when you have a tire replaced outside at a temperature different from the "cold" temperature (70°F) standard.  Tire pressure changes about 2% for every 10°F (assuming it's dry air).  From charts available online to estimate the changes, if you set your 95 PSI pressure @ 68°F (as close as the chart gets - it's based on °C) you should have read about 103.6 at 110°F.  Now, if you re-adjusted the pressure when the tires were at 110°F to 95 PSI, when you get back to the "standard" "cold" temperature of 70°F, you'll only have about 86.3 PSI, which is likely underinflated.  I won't bore you with the math for 105 PSI, but you get the idea.  If you have to adjust tire pressure, especially when it is quite different from the "Standard Cold" temperature of 70°F, you must use temperature compensation.  This applies to colder than "Standard Cold" also.  

[JDCrow]

22 minutes ago, waterskier_1 said:

You should never re-adjust tire pressure based on outside temp changes unless you have a valid reason to suspect they were not adjusted correctly originally.  This could occur when you have a tire replaced outside at a temperature different from the "cold" temperature (70°F) standard.  Tire pressure changes about 2% for every 10°F (assuming it's dry air).  From charts available online to estimate the changes, if you set your 95 PSI pressure @ 68°F (as close as the chart gets - it's based on °C) you should have read about 103.6 at 110°F.  Now, if you re-adjusted the pressure when the tires were at 110°F to 95 PSI, when you get back to the "standard" "cold" temperature of 70°F, you'll only have about 86.3 PSI, which is likely underinflated.  I won't bore you with the math for 105 PSI, but you get the idea.  If you have to adjust tire pressure, especially when it is quite different from the "Standard Cold" temperature of 70°F, you must use temperature compensation.  This applies to colder than "Standard Cold" also.  

Thanks for answering. We are all square now, I’ll leave them alone! Just put in the TMPS so hopefully it will keep me straight 

[waterskier_1]

27 minutes ago, JDCrow said:

Thanks for answering. We are all square now, I’ll leave them alone! Just put in the TMPS so hopefully it will keep me straight 

Just remember that as you drive, the tire temperature will increase, and so will the tire pressure.  The Tire Engineers designed the tire knowing this.  I just watch all my tires, and as long as they are are going up about the same amount, I don't worry.  The Actual Pressure (or Temperature) is not as important as the TREND in temperature and/or pressure.  

 

[JDCrow]

2 minutes ago, waterskier_1 said:

Just remember that as you drive, the tire temperature will increase, and so will the tire pressure.  The Tire Engineers designed the tire knowing this.  I just watch all my tires, and as long as they are are going up about the same amount, I don't worry.  The Actual Pressure (or Temperature) is not as important as the TREND in temperature and/or pressure.  

 

Ok, will keep an eye on them all. I had one sensor go to no signal in first 10 mins so need to Change out the battery. Kinda bummed this thing doesn’t turn off at all. 
 

And you have one of the all time great engines, Series 60. You have the 470/500 or a newer model? The 470/500 was just a reliable beast. 

Edited October 28, 2021 by JDCrow

[Dr4Film]

3 hours ago, waterskier_1 said:

You should never re-adjust tire pressure based on outside temp changes unless you have a valid reason to suspect they were not adjusted correctly originally.

Sorry, but I have to disagree with what you stated about not re-adjusting tire pressure based on outside temp changes. Whenever I leave Florida or California and head for Alaska I always set the cold psi for the ambient outside air temp on that day we are leaving. Then usually sometime while up in Canada I have to re-adjust the cold psi as the outside ambient temps have gotten a lot colder than in Florida or California when I first started so the air pressure in the tires can be 5 psi or more lower. So I will add more air to compensate for the difference in morning temps. If I don't then all of the sensors are alarming until I am miles down the road. My Low Air Pressure alarm is set for the minimum cold psi needed to carry the weight so I never want to go below that level.

[vanwill52]

4 hours ago, JDCrow said:

Depends on the rate of the spring. 

Yep was just outside on my way to the store 

Those look fine.  I've always LOOSELY criss-crossed multiple loops of 3/16 nylon cord around the crossing point of the bars just on the off-chance one ever broke loose.

[waterskier_1]

52 minutes ago, Dr4Film said:

Sorry, but I have to disagree with what you stated about not re-adjusting tire pressure based on outside temp changes. Whenever I leave Florida or California and head for Alaska I always set the cold psi for the ambient outside air temp on that day we are leaving. Then usually sometime while up in Canada I have to re-adjust the cold psi as the outside ambient temps have gotten a lot colder than in Florida or California when I first started so the air pressure in the tires can be 5 psi or more lower. So I will add more air to compensate for the difference in morning temps. If I don't then all of the sensors are alarming until I am miles down the road. My Low Air Pressure alarm is set for the minimum cold psi needed to carry the weight so I never want to go below that level.

IF you are setting the cold PSI COMPENSATED for the difference between ambient air and the "Standard Temperature" that the Tire Manufacturer bases his pressures upon, then that is okay.  

Done correctly (meaning compensated correctly), then yes, your air pressure will be less at a lower temperature.  But if you apply the compensation factor to normalize it back to the "Standard Temp" of 70°F, you'll see there is no need to adjust.  The key thing to remember is that all the pressures relate ONLY to Standard Temp of 70°F.  If it is not that temp when you check the tires, then you need to compensate for the difference.  This is all based on Boyle's Law.  As the temp increases, the pressure will increase.  As the temp decreases, the temp will decrease.  

Since the tire manufacturer's have no idea if you'll be checking the pressure at Dead Horse, Alaska when is -50°F or in Death Vally at 125°F, they have to settle on a "Standard Temperature" to make any sense of their tables.  Get back to me if I might help clarify or explain how your experience doen't mesh with science.  This is a quite misunderstood subject.  

[Ivylog]

5 hours ago, JDCrow said:

Replace airbags with springs…Depends on the rate of the spring. 

One person posted a drive axle of 17,000 lbs but mine is 23,000 lbs…a 6,000 lbs difference and why I’d be dragging the hitch. Also, you couldn’t adjust the amount the tag supports.