Some advice on a Chevy Suspension Upgrade

[booster]

Has anyone tried Gabriel Highjacker shocks on the rear? I put a pair on an old Mazda MPV and lifted the rear considerably. I've seriously abused them using the van as a ranch truck and they never have lost pressure. I can raise and lower the van at will. Gabriel also makes a GasSLX shock for heavier applications.

Air shocks are physically limited in how much weight they can pick up simply because of their small diameter. The Gabriel site lists the Highjackers as able to pick up 1100# per pair at a whopping 200psi of air pressure. That kind of pressure may be very hard to find for fills. If the shocks are running at a big angle as mentioned and some do, that can also reduce the effectiveness.



Most of us with air bags bags run 40-60psi so are picking up 2-3000# of the load on the rear.


I don't think we have ever heard of anyone using air shocks in vans to this point. Spring changes and airbags have been done quite a bit on all brands of class b's. Some Sprinters have even gone full rear air ride.

 

[alaskasail]

i installed the Gabriel MAX Control shocks four years ago, about 70k miles on them now. They still work just fine. up front, thinking it is getting near time on the rear for replacements. I did call Gabriel up and explained what I had and the weight involved, they recommended the MAX Control. I don't see the harm in trying the air shocks in the rear but with the angle that the shocks sit at, may not be fully beneficial.

If you do try the air shocks, please post up how they are working out.

I didn't find the Max shock for the front on the Gabriel site, but I'll give them a call. Anyway, I'm thinking that I would use the Hijackers only when necessary, like when I'm off off-the-beaten-track and need a little more clearance. During regular operation. I would have them in the lower position. I guess one issue is that these are basically fully loaded one-ton vans and heavier shocks are indicated.

 

[booster]

I didn't find the Max shock for the front on the Gabriel site, but I'll give them a call. Anyway, I'm thinking that I would use the Hijackers only when necessary, like when I'm off off-the-beaten-track and need a little more clearance. During regular operation. I would have them in the lower position. I guess one issue is that these are basically fully loaded one-ton vans and heavier shocks are indicated.

I totally agree on the one ton van needing the best shocks you can put on them. We use Bilsteins like many others, Fox is making some nice variable rate stuff now, others use the high end Monroes, KYB, and some other brands. We found that having the variable damping was a big benefit as higher control shocks can harshen the ride. Unless things have changed over the years, most air shocks don't usually have a really good shock section, although it has been years since I used them on anything and never on anything approaching 5 tons.


I did not look at any vehicle specific information on site, just the information blurb that gave max gain and air pressure range. When folks have looked for air shocks in the past, IIRC, they were not able to find much.


I just looked the vehicle specific information and no air shocks for Chevy 3500 shown, and no Max for the front shown.


It appears you have a Chevy similar to our C19P Roadtrek 2007.

 

[angelmroman]

Following the Lead of other Chevy Owners on this Forum, had these upgrades done;
1). Bilstein Shocks
2). Sumo Bump Stops

The increase in Ride comfort was DRAMATIC. The Sumos raised the rear 1 1/2”. Greatly reduced the “Lean” in turns, off-Ramps and the “Bounce” over Speed Bumps, Driveways, etc.

Having said that, it was still annoying how HARSH the Ride was at the Front End. Attached are two Photos, before and after, of the next upgrade. Moog 81004 Coil Springs.

I expected a 2”-2 1/2” increase with the Springs. I got 4” (!). The change lifted the Nose off the Bumps Stops. That made all the difference. Have driven about 200 miles since. Again, the improvement was DRAMATIC. The FREAKIN RATTLE over Bumps, Pot Holes, rough Surfaces has been virtually eliminated. Money WELL SPENT! .

PS....For whatever reason, the 2nd Photo would not upload vertically. Sorry :-(.

 

[booster]

Following the Lead of other Chevy Owners on this Forum, had these upgrades done;
1). Bilstein Shocks
2). Sumo Bump Stops

The increase in Ride comfort was DRAMATIC. The Sumos raised the rear 1 1/2”. Greatly reduced the “Lean” in turns, off-Ramps and the “Bounce” over Speed Bumps, Driveways, etc.

Having said that, it was still annoying how HARSH the Ride was at the Front End. Attached are two Photos, before and after, of the next upgrade. Moog 81004 Coil Springs.

I expected a 2”-2 1/2” increase with the Springs. I got 4” (!). The change lifted the Nose off the Bumps Stops. That made all the difference. Have driven about 200 miles since. Again, the improvement was DRAMATIC. The FREAKIN RATTLE over Bumps, Pot Holes, rough Surfaces has been virtually eliminated. Money WELL SPENT! .

PS....For whatever reason, the 2nd Photo would not upload vertically. Sorry :-(.

You would be, I think, number three that got much more lift than in the past with the 81004. There really seems to be something going on with that. I think I will contact Moog and see what they say, but they are not easy to get any answers out of.


Looking at the pic, it appears that there is a non factory bump stop at the lower arm that is nearly contacting control arm. At 4" above the low Roadtrek ride you would normally be maybe 3/4" off the bump stop. If that an aftermarket lift type bump stop?


Re the 4" of lift. That would normally put the front wheel wells at 37.5" to 38.0" high. This is where the bad Erb springs I tested had ours sitting. I am actually very surprised they could get the shock to bolt up, as the Bilstiens I had were too short unless I moved the mount from under the arm to above.


Now the "please take a look" very soon, thing. At 4" of lift you start to get so high that the upper control arm is nearly hitting the frame of the van in the area just outboard of the bushings. Ours had very little clearance left at that point, so almost no allowable down travel of the wheel on bumps before the arm hits frame and could get damaged. There is not protective bump stop on down travel so the shock does the stopping. If the shock is long enough to mount up at that height it could also let the frame contact the arm. Even if the shock does stop the travel before contact, at that height you would likely be topping out the shocks a lot, which is not a good thing. My worry would be if you have a possible contact it could get quite expensive to fix.



I will go back and find my Erb thread and see if I have pix of that condition to compare to.

 

[angelmroman]

Hey booster. Thanks again for all of your Recommendations in the past .

1). The first Photo was taken after the initial Upgrade (Bilsteins and Sumos). The Sumos were bright yellow in color. Ran that set-up for several months. As I said earlier, as much as the Ride was improved, more was needed. Then the Moogs were added. By then, the Sumos coloring had changed.

2). I also added BFG KO2 Tires (265/75R16.1” taller than Stock). Finished Ride Height is 37” at the front Wheel Well. Total increase is 4 1/2” at the Nose. 2” at the Tail. Going to run this setup for a bunch of miles. I MAY add Air Bags .

 

[booster]

Here is a pic of the area you need to look at. Two places on each upper arm that might contact, front and rear of arm.

Look at that gap with the van on ground and note the gap . Then jack it up from the frame so the wheel hangs on the shock and check the gap. At this point most would say you need 1/4 to 3/8" gap to allow for momentum making it go lower by compressing the shock upper mount.



If the gap doesn't change much, you will have very little down travel and top out the shocks. If there is any question, you need to measure how much downtravel you really have. 2" is about as low on downtravel as I like, but some are OK at less.


If it the arm hits the frame when jacked up, don't drive it much or over big bumps until you get it so it won't hit.


I forgot to ask in the first reply. What is you current wheel well height? Stock tires?

 

[booster]

Hey booster. Thanks again for all of your Recommendations in the past .

1). The first Photo was taken after the initial Upgrade (Bilsteins and Sumos). The Sumos were bright yellow in color. Ran that set-up for several months. As I said earlier, as much as the Ride was improved, more was needed. Then the Moogs were added. By then, the Sumos coloring had changed.

2). I also added BFG KO2 Tires (265/75R16.1” taller than Stock). Finished Ride Height is 37” at the front Wheel Well. Total increase is 4 1/2” at the Nose. 2” at the Tail. Going to run this setup for a bunch of miles. I MAY add Air Bags .

Now we are making progress!


I just went out and measured ours, which doesn't have Moog 81004 springs in it but they are identical and give the same lift as the Moogs have in the past. We also have the 265-75-16 tires. We are right at 36" at wheelwells right now, lightly loaded. Our springs are nearly a decade old now so have gone a little maybe a 1/4". Tires are worn maybe 1/8" on radius.


I would expect that you will go down at least 1/4" as the springs seat and age a bit. Maybe more if the put in the new version of the upper rubber spring cushion, as they now are all rubber without the metal reinforcement like the originals had.


At our 36" I have the shocks spaced down as far as the thread allows, maybe 1/4", with washers on the top of the shocks. With that we get about 2" of down travel. I would expect at 37" high and if we have the same shocks, which is likely, you are going to have quite a bit less downtravel than we have, maybe less than 1", so you probably want to at least check that. You get double the spacer thickness at the shock in downtravel with the geometry, and it is an easy thing to do if it will give you enough fix.


For reference, we have about 1" of gap between the upper arm and the frame when sitting on the wheels.


At that height, you might start to feel a bit of bump steer. When we were an inch higher than that bumps steer was quite bad.


As always after a lift the wheels need to be aligned, particularly the toe which can change a lot with that much height change.


It does appear you got about an inch more lift than in the past, but not the 2" more that some have gotten, which is way too much. Will be interesting to see where you are at after 10K miles and things have settled.

 

[alaskasail]

I was looking up the Moog springs and see some wildly different prices on them. Anyone have experience regarding that. Are there some counterfeit springs out there?

 

[Asphalt Addict]

When I was looking I too found some confusion. I remember reading a review by someone who bought the cheaper ones and they were not to the specs he thought he was getting. I ended up buying them from the suspension shop that put them in. I paid a few bucks more but thought it was worth it. If I brought in my own springs I'd have to pay their labor even if they didn't fit. Too much hassle and worry. Moog in front, air lifts in rear. The ride is waaaay better. Good luck.

 

[Bjones7788]

I have two Chevy Roadtrek 190s.

To get better ground clearnace I put the taller Moog front coil springs on and AirLift 5000 rear air bags plus Bilstiens all around .

Ride was noticably harder - wife, who hung out innback fir years refused to ride back there - so removed air bags and installed 3 inch lift blocks between the rear axle and leaf springs which gave us the original softer ride in the rear.

That worked well enough that I installed 3" lift blocks on our older (2004) Vhrvy Roadtrek 190

Next I had small about one onch thick spacers from Chassis-Works near Las Vegas (there are other companies named Chassis Works) installed under the front coil springs on the older 2004 Roadtrek 190. The manufacturer claimed I would get a 2.5" front end lift which did not seem.posdible to me, but using a bubble level across from the under side of the front fenders to a longer than usual "yard" stick going up from our garage floor to the bubble level, I actually measured 2.5 " lift.

The Moog springs I had installed on the newer Chevy 2013 Roadtrek 190 gave me something over 4" of front end lift which seems to be the case with the more recent Moog springs rather than closer to 3" as I recalnothers reporting.

As I walk by the front of the old RT with 2.5 " front end lift my eye says the RT is taller and whrn I walk by the newer RT my eye says this one is rwally taller.

I hope the front end soacers give me a softer ride than the stiffer recent vintage Moog front end coil springs which seem pretty stiff.

I have not driven the older RT with front spscers much yet to see if the spacers. Which are aluminum, hold up and give me the same old soft ride. A warning - the fitst shop I asked to install the front spacers. said they were too narrow and would not fit. Suggesting they would be damaged during use because the outer edge of the coil springs extend outside of the groove in the spacers. The manufscturer said they look like they will not fit but "seat" nicely under load.

I suspect time and driving will tell how these concerns work out. I will try to report.

 

[booster]

I have two Chevy Roadtrek 190s.

To get better ground clearnace I put the taller Moog front coil springs on and AirLift 5000 rear air bags plus Bilstiens all around .

Ride was noticably harder - wife, who hung out innback fir years refused to ride back there - so removed air bags and installed 3 inch lift blocks between the rear axle and leaf springs which gave us the original softer ride in the rear.

That worked well enough that I installed 3" lift blocks on our older (2004) Vhrvy Roadtrek 190

Next I had small about one onch thick spacers from Chassis-Works near Las Vegas (there are other companies named Chassis Works) installed under the front coil springs on the older 2004 Roadtrek 190. The manufacturer claimed I would get a 2.5" front end lift which did not seem.posdible to me, but using a bubble level across from the under side of the front fenders to a longer than usual "yard" stick going up from our garage floor to the bubble level, I actually measured 2.5 " lift.

The Moog springs I had installed on the newer Chevy 2013 Roadtrek 190 gave me something over 4" of front end lift which seems to be the case with the more recent Moog springs rather than closer to 3" as I recalnothers reporting.

As I walk by the front of the old RT with 2.5 " front end lift my eye says the RT is taller and whrn I walk by the newer RT my eye says this one is rwally taller.

I hope the front end soacers give me a softer ride than the stiffer recent vintage Moog front end coil springs which seem pretty stiff.

I have not driven the older RT with front spscers much yet to see if the spacers. Which are aluminum, hold up and give me the same old soft ride. A warning - the fitst shop I asked to install the front spacers. said they were too narrow and would not fit. Suggesting they would be damaged during use because the outer edge of the coil springs extend outside of the groove in the spacers. The manufscturer said they look like they will not fit but "seat" nicely under load.

I suspect time and driving will tell how these concerns work out. I will try to report.

Thanks for information BJ. It will be interesting to see how the spacers do. I don't recall the brand, but I have seen aluminum spacers that were claimed to be specifically for the vans. Don't recall available thicknesses, but they did have a spring fitting pocket in them which would probably fit the spring better than the flat top mount that is built into the van.


2.5" from a 1" spacer is what you would expect as that is right about at the ratio of the spring pocket location to the tire center location from the lower control are pivots.


The only thing you might see with the space and a stock spring would be the possibility of taking it solid or past yield on a big bump. The solution is pretty easy as all you would need would be a taller bump stop on the lower arms. Since the factory system was so low, it was hitting that bump stop a lot which added some firmness and progression and you won't have that now, so you may find the front ride to be softer than before. Hopefully, it won't be so soft it porpoises, though.

 

[Bjones7788]

The spacers under the front coil springs for my 2004 Chevy Express 3,500 camper van that I discussed in my previous post have a cut out in their citcumference so i presume they may not require as much front suspension dissambly as replacing the springs with taller, stiffer Moogs and the spacers cost $39.95 for a set of 2 spacers which is less expensive than new springs.

 

[booster]

The spacers under the front coil springs for my 2004 Chevy Express 3,500 camper van that I discussed in my previous post have a cut out in their citcumference so i presume they may not require as much front suspension dissambly as replacing the springs with taller, stiffer Moogs and the spacers cost $39.95 for a set of 2 spacers which is less expensive than new springs.

The upper spring pocket if very deep so you still would need to compress the spring a bunch I think. They didn't put them in the bottom did they?

 

[peteco]

I have two Chevy Roadtrek 190s.

To get better ground clearnace I put the taller Moog front coil springs on and AirLift 5000 rear air bags plus Bilstiens all around .

Ride was noticably harder - wife, who hung out innback fir years refused to ride back there - so removed air bags and installed 3 inch lift blocks between the rear axle and leaf springs which gave us the original softer ride in the rear.

That worked well enough that I installed 3" lift blocks on our older (2004) Vhrvy Roadtrek 190

Next I had small about one onch thick spacers from Chassis-Works near Las Vegas (there are other companies named Chassis Works) installed under the front coil springs on the older 2004 Roadtrek 190. The manufacturer claimed I would get a 2.5" front end lift which did not seem.posdible to me, but using a bubble level across from the under side of the front fenders to a longer than usual "yard" stick going up from our garage floor to the bubble level, I actually measured 2.5 " lift.

The Moog springs I had installed on the newer Chevy 2013 Roadtrek 190 gave me something over 4" of front end lift which seems to be the case with the more recent Moog springs rather than closer to 3" as I recalnothers reporting.

As I walk by the front of the old RT with 2.5 " front end lift my eye says the RT is taller and whrn I walk by the newer RT my eye says this one is rwally taller.

I hope the front end soacers give me a softer ride than the stiffer recent vintage Moog front end coil springs which seem pretty stiff.

I have not driven the older RT with front spscers much yet to see if the spacers. Which are aluminum, hold up and give me the same old soft ride. A warning - the fitst shop I asked to install the front spacers. said they were too narrow and would not fit. Suggesting they would be damaged during use because the outer edge of the coil springs extend outside of the groove in the spacers. The manufscturer said they look like they will not fit but "seat" nicely under load.

I suspect time and driving will tell how these concerns work out. I will try to report.

Do you have part number and source for the spacers? With the problems with the new springs these may be the answer.

 

[markopolo-ClassB]

................... The only thing you might see with the space and a stock spring would be the possibility of taking it solid or past yield on a big bump. The solution is pretty easy as all you would need would be a taller bump stop on the lower arms. Since the factory system was so low, it was hitting that bump stop a lot which added some firmness and progression and you won't have that now, so you may find the front ride to be softer than before. Hopefully, it won't be so soft it porpoises, though.........

Along the lines of Booster's points:

If increased ground clearance is the goal and the ride, handling and control of the van is acceptable then spacers look to be an option.

I looked into using spacers on the front but did not like that they would permit the coils to be compressed more than the original suspension design allowed for. By the time the bump stop started to protect the coil it would compressed more than it could have been prior to installing the spacer. The risks could be breakage of the coil or increased likelihood of the coil sagging further.

I also looked into using spacers for the rear but the leaf spring pack looked pretty much flat on my van which was 19 years old.

Also, increased ground clearance wasn't the primary goal for my van. More effective suspension and eliminating porpoising and sway were the primary goals and the Moog coils, AirLift bags, Bilsteins & anti-sway bar eliminated all control issues.

It seems to me that new springs or at least helper springs will be needed at some point on most of these heavily loaded vans given that they will be likely be on the road for a few decades.

 

[StreaminGuy]

Koni FSD opinion

I've concluded that I have every incentive to leave well enough alone.

I have zero complaints regarding ride and handling. So I'll just continue to be careful about the ride-height limitations, leave my '2012 Chevy 35000-based Avenue stock (except for new Koni FSD shocks), and enjoy the ride.

For those seeking to improve their rv, I'll continue to monitor this thread and look forward to what works for you.

Rowie Bowie, did you install the Koni FSD's? If so, what are your thoughts on them?

Thanks, G
2012 Airstream Avenue Suite (White)

 

[rowiebowie]

Rowie Bowie, did you install the Koni FSD's? If so, what are your thoughts on them?

Thanks, G
2012 Airstream Avenue Suite (White)

I'm in communication with StreaminGuy since we share a common ownership of an Airstream Avenue Suite. A rare bird indeed.

For others here on the Chevy Express Chassis, I will update that after nearly 7 years and 50K miles, the Koni FSD's are still providing a comfortable and well controlled ride. I notice no apparent degradation from when they were installed new. I'm very satisfied and consider the pricey cost as money well spent.

ps - I had a 2-1/2" lift installed about the mid-point of my Koni FSD ownership. The provided rear shock extenders in the kit allowed me to keep the Koni's and they still control my slightly lifted van as well as they did before.

 

[phantomjock]

rowiebowie-

Looking forward to the long-term analysis. Going through this thread, it appears that your "lift" was all shock extenders, then the 2-1/2" lift kit? Kit details? You haven't mentioned Air Bags. Installed - or no? The kit providers?

If you have a BOM to go with it - that would be really Great! I'm looking for a "Sightly Lifted Express Chassis."

Cheers - Jim

 

[booster]

rowiebowie-

Looking forward to the long-term analysis. Going through this thread, it appears that your "lift" was all shock extenders, then the 2-1/2" lift kit? Kit details? You haven't mentioned Air Bags. Installed - or no? The kit providers?

If you have a BOM to go with it - that would be really Great! I'm looking for a "Sightly Lifted Express Chassis."

Cheers - Jim

Hi Jim, the "slightly lifted" Chevy van lift if probably the one that most of us have done and is in the 2-3" range. Many discussions on those lifts here on the forum.


What the lift does is not even really a lift as it will put most Chevies back at the factory spec ride height. A Roadtrek 190 is about 2" lower than stock spec after conversion for instance. The 170s that are on the short 2500 chassis haven't been done as much and might need to be a bit different.


The norm is replacement front coils and Airlift bags or leaf spring work in the rear. I am a big fan of the bags over spring changes as it will also give a smoother ride in most cases. I am not a fan of spring spacers on either end. There have been some knuckle lifts to get 4+ inches and others can address them. I don't care for knuckle lifts or really high as I want the van to handle as well as possible in the 98% of the use which is on road and often in big winds. High and knuckle lifts can compromise the handling in many cases, IMO.


Along with lifts, some of us have added big rear sway bars to reduce the large understeer in the vans. Many have improved shocks, most commonly with Bilstein but others have like other models also.


Going to 265-75-16 tires will also give you and extra 1/2 of road clearance, and on the 190s and especially 210s, the extra 350# load capacity is a very good thing in the rear where they stock tires are often at load capacity.