Chevy Suspension Upgrade Complete

[peteco]

I should add that booster (and others) experience is most helpful on suspension and other items discussed here.

It would be interesting to see the engineering analysis associated with the Firestone R4 tech system mentioned previously. Surely the design used the component material characteristics (spring rates, etc), along with some trial and error as well.

[booster]

Originally Posted by peteco

I should add that booster (and others) experience is most helpful on suspension and other items discussed here.

It would be interesting to see the engineering analysis associated with the Firestone R4 tech system mentioned previously. Surely the design used the component material characteristics (spring rates, etc), along with some trial and error as well.

There probably is a program somewhere that can, maybe has, modeled some of this stuff for aftermarket. I would guess that it would be pretty straight forward for a van sitting on 4 wheels, but would get much more dynamically complex if you add a hitch, equalization bars, various over hangs, etc. One trailer parameter that doesn't ever seem to get mentioned, which I think would be a big factor on bouncing, would be the weight distribution on the trailer axles with the trailer on the tow vehicle and equalized. I would think how the weight is on the axles, along with the center gravity, would determine how much and around what center the trailer would rotate and gain momentum. Even a hitch height change due to ride height change in the tow vehicle would change the axle weights on the trailer, I would think.


It would also be pretty interesting to see what a logging accellerometer would read if put on the tongue with and without the airbags in Bob's van.

[Bjones7788]

SKIP TO THE LAST PARAGRAPH FOR MY QUESTION or read the following refresher:

I have a 2013 Chevy Roadtrek 190 Popular with about 4" lift in front from Moog springs and Bilstien shocks.
Bilstiens were installed along with Air Lift 5,000 air bags on the rear, with lift dependent on air pressure and I am very very happy with increased ride height.

However, My wife used to sleep in back for 100 plus miles as I drove prior to the air bags but says she gets thrown up in the air and cant sit or lay down in back while I drive now - with the air bags deflated, part way inflated or fully inflated.

This is true when I tow a 7,000 pound trailer as well regardless of air bag inflation pressure, and

Now tools that hang on the front walls of my trailer bounce off which did not happen prior to the air bags. Again this is even with changing pressure in the air bags from 5 to 50 to 95 PSI.

I have not tried PING tanks yet.

I did swap the Bilstiens for high end NAPA house shocks just in case the shocks were the problem, thinking that to be unlikely but easy to try.

Next, I unplugged the power to the air bags and removed them - very easy. That seems to have eliminated the rear end hop. I do need to do some more open road driving with and without the trailer to be sure.

In the mean time the questions arises.

IF the air bags are the cause of the rear end hop, is there a reason not to leave them off and lift the rear by placing (3") spacers between the top of the rear axle and the bottom of the springs. It seems this should give me original ride prior to the air bags because the rig would be back to near level and the rear springs would be back to normal function without what I think at this point was air bag induced bounce or hop??.

Bob J
443-480-1023
drjones7788@gmail.com

[booster]

Originally Posted by Bjones7788

SKIP TO THE LAST PARAGRAPH FOR MY QUESTION or read the following refresher:

I have a 2013 Chevy Roadtrek 190 Popular with about 4" lift in front from Moog springs and Bilstien shocks.
Bilstiens were installed along with Air Lift 5,000 air bags on the rear, with lift dependent on air pressure and I am very very happy with increased ride height.

However, My wife used to sleep in back for 100 plus miles as I drove prior to the air bags but says she gets thrown up in the air and cant sit or lay down in back while I drive now - with the air bags deflated, part way inflated or fully inflated.

This is true when I tow a 7,000 pound trailer as well regardless of air bag inflation pressure, and

Now tools that hang on the front walls of my trailer bounce off which did not happen prior to the air bags. Again this is even with changing pressure in the air bags from 5 to 50 to 95 PSI.

I have not tried PING tanks yet.

I did swap the Bilstiens for high end NAPA house shocks just in case the shocks were the problem, thinking that to be unlikely but easy to try.

Next, I unplugged the power to the air bags and removed them - very easy. That seems to have eliminated the rear end hop. I do need to do some more open road driving with and without the trailer to be sure.

In the mean time the questions arises.

IF the air bags are the cause of the rear end hop, is there a reason not to leave them off and lift the rear by placing (3") spacers between the top of the rear axle and the bottom of the springs. It seems this should give me original ride prior to the air bags because the rig would be back to near level and the rear springs would be back to normal function without what I think at this point was air bag induced bounce or hop??.

Bob J
443-480-1023
drjones7788@gmail.com

From post 158 of mine

Since you have a 190 as I recall, it would have come from the factory without any lift blocks in it like they put on the 210s with more overhang and rear weight. Since you probably will get the ride you want when sitting on the overload leafs, you could just put in 2" blocks to get the lift you want. The blocks go under the springs, so the springs should function the same before and after adding the blocks. At a minimum, it would tell you if it is height or spring rate giving you the issue.

I am still leaning that way, now. You (and more importantly your wife) appear to be OK with the ride quality with no bags, but the increased motion of adding the bags is the issue. A simple block lift would leave just what you like in the springing so shouldn't change the ride in itself. What you will also learn is if the added height is changes the dynamics of the trailer movements. If it does, then all you would need to do is use a drop hitch of the same dimension as the lift was.


The only downside to the blocks I could see would be the possibility of getting more axle side to side movement with higher mechanical advantage on the spring supports. Worst case, not likely, might be the need to add a track arm to hold the axle in place.

[Bjones7788]

Guys, I just caught up on the last few posts you put up (after I sent my previous post a few minutes ago) SORRY.
I should note that I bet many Roadtrek ownrs would not pay much attention to my hop problem. My test equipment (wife) and her propensity to want to sleep and lounge in back for long portions of our trips is somewhat unique I bet. And the folded wing putting a LOT of load thru the thin aft fuselage onto the tail wheel is a big concern to me becasue the load bouncing load transferring thru the fuselage has caused bent fuselages for others who tow like I do. (The tail of the plane is in the front of the trailer where tools are hopping off their hooks., so hop in that area scares me)
Getting to the right AirLift 5,000 engineer has eluded me so far, but makes sense.
I do agree that the internal jounce stop may well be involved particularly if the removal of the air bags eliminates the problem.
I am about to order 3" spacers for between the rear axle and rear springs but wanted to hear from you guys if this presented concerns, thus the earlier post that is out of sequence.
Again more when I know more and
THANK YOU BOTH !

Bob J

[peteco]

Originally Posted by Bjones7788

I am about to order 3" spacers for between the rear axle and rear springs but wanted to hear from you guys if this presented concerns, thus the earlier post that is out of sequence.

Bob J

Question for booster: is another possible option to consider custom springs that are bowed to give the right lift?

[booster]

Originally Posted by peteco

Question for booster: is another possible option to consider custom springs that are bowed to give the right lift?

Absolutely, IMO, that would be possible. I do think it might be hard for anyone to determine what rate to make them, though, as the stock spring on the overload is kind of hard to duplicate. As we have seen, it appears that spring rate and progressiveness of the rear springs is OK on the stock springs with overload leafs, as Bob and DW like the way it rides. I would worry about missing that sweet spot with new springs, I think.

[Bjones7788]

Interim report on rear end bounce in our Chevy Roadtrek 190s.

I put my test equipment on the back bench seat of both our 2004 and 2013 Roadtrek 190s and drove thru a well know course including two separate areas with road swales, that are well known to cause the vehicles to pitch up and down, then we went along a course with a variety of well know speed bumps, all at predetermined and closely matched speeds for each vehicle.

These were done with standard very old OEM 211,000 mile suspension under the 2004 RT 190 and for comparison with the 2013, (53,000 miles) but Moog front springs & Bilstiens and rear Airlift 5,000 air bags REMOVED from the 2013 & using a set of NAPS's highest grade shocks.

The purpose was 1. to determine if we think the air bags contributed to a very prominent bounce or hop when we had them in position in the 2013, and
2. is there a significant difference between the old 2004 ride quality and the 2013 ride quality based on older more worn suspension.

Clinical impression from my test equipment wife who has spent way too much time lounging in the back of both vehicles and was clear with me that she could no longer safely ride in the rear of the 2013 after installation of Moog springs up front and rear air bags:

1. Wife says she can now sleep, lounge and do cell phone business safely in the rear of the 2013 without air bags. The big picture is the bounce or hop in the rear seat has improved enough with air bags removed for her to pronounce a clear observational winner.

2. She also noted that the 2013 has a much firmer OEM rear bench seat than our 2004 because I had removed the OEM seat from our 2004 and installed a much deeper and softer multi-layer foam cushion. She also felt that the 2013 had a slightly harder ride than the 20014 which may be primarily due to the difference in seat firmness but may also be due to suspension difference.

3. The Moogs up front do result in a harsher front ride. I must note that our very recent Moog front springs gave us nearly 4 inches of additional ground clearance which is much more than reported by most for that upgrade. So for whatever reason our Moog springs are probably much stiffer than most installations contributing to a harsher ride up front.

Back to the 2013 with air bags removed, In neither vehicle did her body come up off of the seat as it had with air bags installed in the 2013. This phenomenon was prominent to the point that she would no longer lounge back there. (BTW, That meant of course that I gained a backseat driver sitting next to me up front in the air bag equipped RT. Enough said on that unintended consequence.)

So next test is with rear spacers installed between the rear axle and leaf springs to obtain a more level vehicle attitude.
Then a trial with the 7,000 pound aircraft trailer hooked to Roadtrek to determine if the tools remain hanging in the front of the trailer as historically has been the case. This will be the most objective test.

More when I know it.

BJ

[booster]

Originally Posted by Bjones7788

Interim report on rear end bounce in our Chevy Roadtrek 190s.

I put my test equipment on the back bench seat of both our 2004 and 2013 Roadtrek 190s and drove thru a well know course including two separate areas with road swales, that are well known to cause the vehicles to pitch up and down, then we went along a course with a variety of well know speed bumps, all at predetermined and closely matched speeds for each vehicle.

These were done with standard very old OEM 211,000 mile suspension under the 2004 RT 190 and for comparison with the 2013, (53,000 miles) but Moog front springs & Bilstiens and rear Airlift 5,000 air bags REMOVED from the 2013 & using a set of NAPS's highest grade shocks.

The purpose was 1. to determine if we think the air bags contributed to a very prominent bounce or hop when we had them in position in the 2013, and
2. is there a significant difference between the old 2004 ride quality and the 2013 ride quality based on older more worn suspension.

Clinical impression from my test equipment wife who has spent way too much time lounging in the back of both vehicles and was clear with me that she could no longer safely ride in the rear of the 2013 after installation of Moog springs up front and rear air bags:

1. Wife says she can now sleep, lounge and do cell phone business safely in the rear of the 2013 without air bags. The big picture is the bounce or hop in the rear seat has improved enough with air bags removed for her to pronounce a clear observational winner.

2. She also noted that the 2013 has a much firmer OEM rear bench seat than our 2004 because I had removed the OEM seat from our 2004 and installed a much deeper and softer multi-layer foam cushion. She also felt that the 2013 had a slightly harder ride than the 20014 which may be primarily due to the difference in seat firmness but may also be due to suspension difference.

3. The Moogs up front do result in a harsher front ride. I must note that our very recent Moog front springs gave us nearly 4 inches of additional ground clearance which is much more than reported by most for that upgrade. So for whatever reason our Moog springs are probably much stiffer than most installations contributing to a harsher ride up front.

Back to the 2013 with air bags removed, In neither vehicle did her body come up off of the seat as it had with air bags installed in the 2013. This phenomenon was prominent to the point that she would no longer lounge back there. (BTW, That meant of course that I gained a backseat driver sitting next to me up front in the air bag equipped RT. Enough said on that unintended consequence.)

So next test is with rear spacers installed between the rear axle and leaf springs to obtain a more level vehicle attitude.
Then a trial with the 7,000 pound aircraft trailer hooked to Roadtrek to determine if the tools remain hanging in the front of the trailer as historically has been the case. This will be the most objective test.

More when I know it.

BJ

Thanks for the update, Bob, it is a very interesting story to follow, and your methods are very good and, ahem, methodical


I think that the spacers will do the trick in your case, as much as I would never have said that up front. It does make sense now, sort of...


Moog must have changed vendors on the springs to have such a radical change, as it has been a fairly sharp cutoff line maybe a year ago when everyone started to get way to much lift. Since the lengths have normally checked good, it has to be a much, much, greater springrate in the front and that could really mess up a lot of things. It would be interesting to see what Moog would say about it, although they probably will do the corporate "nothing has changed" stuff we here from manufacturers all the time.

[peteco]

I find it odd that we now have at least 2 manufacturers that changed their spring design from acceptable to unacceptable in our Chevy Roadtreks: TufTruck and now Moog. Now that the Moog springs do not appear to work, what other options presently exist to give the 2-inch front lift that is typically desired?

On the back end, is it the jounce bumper that is causing the harsh bouncing, the bag itself, or both together?

Bob, I wonder if Airlift would provide you with the non-jounce bumper version to try.

[booster]

Originally Posted by peteco

I find it odd that we now have at least 2 manufacturers that changed their spring design from acceptable to unacceptable in our Chevy Roadtreks: TufTruck and now Moog. Now that the Moog springs do not appear to work, what other options presently exist to give the 2-inch front lift that is typically desired?

On the back end, is it the jounce bumper that is causing the harsh bouncing, the bag itself, or both together?

Bob, I wonder if Airlift would provide you with the non-jounce bumper version to try.

I think you can make that three suppliers, with the third being Bill Erb. When I tested his springs I got a 38.125 ride height which was over 4" and way to high for the suspension geometry.


I think Tufftruck has been the only one that adjusted their specs, with the explanation that the diesel engined vans that also had plows on them were needing more springrate, and RVers kept complaining of stiffer ride (which should have been expected in most cases). They discontinued the sales for RVs to concentrate on the other markets to get rid of the hassle. The others are still saying you will get 2" of lift, but it is usually around double that.


I don't think Bob will find that the jounce bumper is a major factor in his issue, as it still did the same problem when aired up to be well above the bumper to get level, as he is very high in the front. Of course most of the guesses on this have not worked out to this point, so anything could happen.

[Bjones7788]

Pete, very interesting suggestion. A call to AirLift to ask about air bags without internal jounce stops is in order plus a little persistence to get to the "right person" to get a nod on that.

Regarding the 4" front end lift from the recent version of Moog front springs - I still love the height increase even though the ride is somewhat harsher then OEM.

We have owned three RT 190s and rented one before that and all had tank support crunch issues before we bought them. We actually started renting a car and staying in motels rather than driving our RT into Mexico because of the very poor ground clearance on our RT 190s.

Booster, what about front strut/spring spacers in lieu of the new and possibly not so improved Moog front spring up grade?

BJ

[booster]

Originally Posted by Bjones7788

Pete, very interesting suggestion. A call to AirLift to ask about air bags without internal jounce stops is in order plus a little persistence to get to the "right person" to get a nod on that.

Regarding the 4" front end lift from the recent version of Moog front springs - I still love the height increase even though the ride is somewhat harsher then OEM.

We have owned three RT 190s and rented one before that and all had tank support crunch issues before we bought them. We actually started renting a car and staying in motels rather than driving our RT into Mexico because of the very poor ground clearance on our RT 190s.

Booster, what about front strut/spring spacers in lieu of the new and possibly not so improved Moog front spring up grade?

BJ

There are finally strong enough spacers to handle the load of the one ton van, although they are a bit tall IIRC. They are aluminum and seemed to look like decent items. To get a bit over 2" lift with a spacer, it appears that a 1" spacer would be enough, but I think these are 2" so more like the 4" lift you have seen. I will have to see if I can find them again, as it has been a while.


Spacers are generally not quite as stable as springs as they can flex because of the the spring being almost out of the top pocket, but I really haven't ever heard of any severe failures because of it.


There is also the possibility of over flexing the stock spring once the bump stop is not there to limit travel, and as of now that has not been tested by anyone. I do think it is a real possibility, though as the stock springs are really soft for a fully loaded Roadtrek.


My mistake, it appears they are calling a 2" lift so might be good with stock springs. Weldtec and Boulder Fab are both offering them.

[peteco]

Here is a spacer that gives 2-inches of lift.

https://weldtecdesigns.com/product/c...ling-spacer-2/

Like booster indicated, the proper spring would be best. Here is one custom shop. There are probably a lot of others but not sure how you find them closer to home.

Coil Spring Specialties

[booster]

Originally Posted by peteco

Here is a spacer that gives 2-inches of lift.

https://weldtecdesigns.com/product/c...ling-spacer-2/

Like booster indicated, the proper spring would be best. Here is one custom shop. There are probably a lot of others but not sure how you find them closer to home.

Coil Spring Specialties

Yep, that is one of them I found on the edit above.


Also agree that there are spring shops all pretty much in most places, but the hard part is getting them to guaranty a specific amount of lift. Most will say "tell me what rate and height you want and we will build it. Of course you have no way to tell if they built it right or not, or if your guess was correct, so it can get really expensive if you have to do it multiple times.

[Bjones7788]

thanks for the spacer source info

I did get to AirLift factory support and Mike immediately understood my problem and offered to sending me a pair of air bags without jounce stops - no charge -

Really impressed with their service ethic.

[peteco]

Originally Posted by Bjones7788

thanks for the spacer source info

I did get to AirLift factory support and Mike immediately understood my problem and offered to sending me a pair of air bags without jounce stops - no charge -

Really impressed with their service ethic.

That's great Bob. Anxious to hear how that turns out. Now if we can find the right front springs.

[peteco]

Hey booster. I seem to recall a gathering of the various spring specs: wire diameter, number of coils, unloaded spring height... Perhaps there was also the resulting lift to the Roadtrek from the springs. I can't find it. Do you recall, or should we recreate? This would help Bob and others. I can measure my TufTruck TTC-1617 springs, but I have the earlier (2011) springs that worked, but not the new Tuftrucks give higher lift and stiffer ride.

[markopolo]

Originally Posted by Bjones7788

............................
Now tools that hang on the front walls of my trailer bounce off which did not happen prior to the air bags. Again this is even with changing pressure in the air bags from 5 to 50 to 95 PSI.

.....................

That must be the most important bit of info needed to solve this. It's happening if over-sprung or under-sprung.

I haven't read all the posts so apologies in advance if I repeat anything that has already been covered.

Is it as simple as stiffer front + introduced upward travel limit in rear = perceived bounce ?

We can all create rear bounce by over-inflating the rear bags and eliminate it (as perceived from drivers seat) by reducing pressure. If the problem isn't over-sprung or under-sprung related then is it rear upward travel related?

As for the front Moogs - you can choose between various models to get the front height you want.

Moog.JPG


I'm curious to know the resultant Z-trim spec after a 4" front rise caused by springs. It must be out of spec ...........

[booster]

Originally Posted by peteco

Hey booster. I seem to recall a gathering of the various spring specs: wire diameter, number of coils, unloaded spring height... Perhaps there was also the resulting lift to the Roadtrek from the springs. I can't find it. Do you recall, or should we recreate? This would help Bob and others. I can measure my TufTruck TTC-1617 springs, but I have the earlier (2011) springs that worked, but not the new Tuftrucks give higher lift and stiffer ride.

IIRC, there is a runup in Photog's long lift thread from a couple of years ago. You might try searching for threads started by him as he hasn't got a lot of them, I think.