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Old 08-02-2018, 05:11 AM   #1
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Default Some advice on a Chevy Suspension Upgrade

I have a 2004 Roadtrek 190 Popular on a Chevy Express 3500 chassis. Weights on the scale are: Front axle 3980 lbs, Rear axle 4820 lbs, Total 8800 lbs. Ground to fender - front: 33.75 - rear 35

Big problem

The van is very low, it scrapes on driveways, speed bumps, road kill, you name it. I need to get it up far enough to drive around town without worry.

I want to be able to take the van off-pavement but not off-road. There are a lot of forest service roads in my area (Southern California) and they are all off-limits to me. My needs in this area are modest, I donít want a mean, lean rock climbing machine. Iíd just like to be able to trundle down a dirt road without fear. I am willing to turn back if things get too rough.

Other Problems

Ride up front is very truck-like. I would like something smoother.
Ride in the rear is like a bouncy carnival ride. I would like to be able to ride passengers back there on occasion.
The handling feels a little drifty. Not too bad. I donít want it worse than it is now.
Airbag leveling at a campsite would be nifty.
I have read the various Bible-sized threads about lifts on these Chevies and gained a lot of useful info. I have learned a lot, but the more technical aspects of suspensions are over my head.

I am thinking that bringing it up 2Ē (or more like 3?) will bring it to stock height and do what I want.

Biil Erb at Valley Spring Works is 6 hours away for me so I am considering going up there and placing myself in his capable hands.

Here is my preliminary parts list
Bilstien shocks all around. These seem to be universally loved
New coil springs up front from Erb
Airlift bags with the internal bump stop
Onboard compressor with remote
Possibly some beefing up of the rear leaf springs by Erb

I know Erb is the man when it comes to springs but I donít know if I should get the airbags installed there. Opinions? Installing airbags is far less technical so I do have options on my area for that.

Thanks for your help, I have learned quite a bit just from reading the existing threads. Very educational and helpful.
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Old 08-02-2018, 12:56 PM   #2
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You likely can get back to unloaded stock height by simply putting in Moog coils in the front and the Air Lift bags in the rear.

http://www.classbforum.com/forums/f8...html#post76498

The ride won't be softer though as you're increasing the spring rate all around. There could be reduced harshness if the old parts previously permitted crashing onto the bump stops.

The combo of front Moog coils, front alignment, rear Air Lift bags, Bilsteins and an rear anti-sway bar will result in great handling characteristics and increased clearance and the feel of an actual working suspension. I think of the resulting suspension as being sport-like ie very far from pillow-top.

Booster went a step further at the rear by removing the massive overload spring allowing the comfort of the rear air bags to be more fully realized.
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Old 08-02-2018, 01:00 PM   #3
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As always, Following a Chevy RT suspension thread!
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Old 08-02-2018, 01:03 PM   #4
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There are lots of threads on the subject here, as the whole thing has gotten settle down pretty well as to what works well.


There is also a thread that I started that covers a test I did with the Bill Erb springs recently, and sad to say, the results and service from Erb were terrible. It cost me lots of wasted time and money. Erb will also not install airbags and would want to put in new springs or extra leafs.
http://www.classbforum.com/forums/f5...ning-6871.html



IMO, the you are on the right track for improvements of ride height and handling response. Here is a list of what have been what I think have given the best results without going way high and messing up the suspension geometry. It will give about 35.75" in the front and 35-37" adjustable in the rear at the wheelwells with stock tires.


*Front springs Moog 81004


*Rear airbags from Airlift that have the internal bump stops


*Bilstein shocks, but using the Chevy upper mounts if the Bilsteins don't come with the Chevy style in the front


* Roadmaster 1.375" diameter rear sway bar, or a Hellwig if you don't have a generator


* Good alignment with as much caster as you can get while holding .5* more caster on the left front. Zero to +.25* camber with no crosscamber. 1/16" toe in if the front end parts are all tight. (Anything questionable should be replaced)



* Optional would be to replace the aluminum wheels, if you have them, with factory steel wheels as the aluminum ones have the wrong offset and that can mess up the steering geometry and cause scuffing.


* Optional two on wheels is to go to Silverado pickup steel wheels of the correct offset, which are wider than the van ones, and go to 265-75-16 tires.


* Tires pressures at 65/80 psi for stock size tires


These changes have seemed to work well for most folks getting them higher without getting excessively harsh and also improving the handling in the process.


As Marko mentioned, this will put you pretty much right at the factory recommended ride height for the van, so all the suspension parts will be in their sweet spot as designed.
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Old 08-02-2018, 03:01 PM   #5
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Quote:
Originally Posted by CaDreamin View Post
I have a 2004 Roadtrek 190 Popular on a Chevy Express 3500 chassis. Weights on the scale are: Front axle 3980 lbs, Rear axle 4820 lbs, Total 8800 lbs. Ground to fender - front: 33.75 - rear 35
CaDreamin.

I really can't add anything to the excellent recommendations already made except to offer a comparison to a similar chassis and measurements. My '2012 Airstream Avenue Suite is also on the Chevy Express 3500. Think of your 190 Popular, swap the galley and baths to opposite sides, and that's my layout.

Concerning your measurements, they do not look off compared to mine. If by fender height you mean from roadway to top of wheel well straight through the center of the tire, my measurements are:

front 34" - rear 34.625"

What is it that scrapes when you drive? Front lower wind split? Tanks underneath? I can take some ground clearance measurement on my for comparison if you give me some reference points. My rv's ground clearance gives me concerns, but I've never scraped it over anything so far and no longer worry about it as much.

Sounds like you definitely need new shocks for better control. Why not start there. If your concerns remain, then you can always go with the other options. Just be sure your wallet is fat enough to survive several thousands in cost if you go the full suspension route.
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Old 08-02-2018, 03:15 PM   #6
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.

Search for photog's thread. Lots of good info.
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Old 08-02-2018, 03:22 PM   #7
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It might be $200 for the pair of Moog coils and $350 for Air Lift Ultimate kit. That's not too expensive to gain probably 2 inches in clearance.

The hanger bolts on the waste tank (can't remember which tank) was the one spot that scraped on the ground on the '04 I had and that was just entering a condo complex parking area.
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Old 08-02-2018, 04:57 PM   #8
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It might be $200 for the pair of Moog coils and $350 for Air Lift Ultimate kit. That's not too expensive to gain probably 2 inches in clearance.

Add labor to install coils & lift kit, plus shocks & labor to install. OP was also considering load leveling which requires pumps and control panel. Wouldn't be unusual on a 14 yr. old motorhome to need some suspension/steering joints replaced as well. That gets pricey and was what I was referring to if that's what it takes to solve his handling and ride issues.

The hanger bolts on the waste tank (can't remember which tank) was the one spot that scraped on the ground on the '04 I had and that was just entering a condo complex parking area.
I agree he needs to look underneath so see what's hanging lowest. His van is not sitting low overall, compared to mine. All I've done on my '2012 is change OEM shocks to Koni FSD's. I've very satsified with ride & handling.

My macerator is my low point, but still 6-1/2" above roadway. Most other areas are about 8" clearance and enough so far as I am careful.
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Old 08-02-2018, 05:52 PM   #9
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I agree he needs to look underneath so see what's hanging lowest. His van is not sitting low overall, compared to mine. All I've done on my '2012 is change OEM shocks to Koni FSD's. I've very satsified with ride & handling.

My macerator is my low point, but still 6-1/2" above roadway. Most other areas are about 8" clearance and enough so far as I am careful.

The Roadtrek macerators and valves tend to be the low point and right where you high center, and yes, he is low just like the rest of us were. The Avenue would weigh about the same and the wheelwell height given would indicate a similar amount low. If you measure the "trim" height for a 3500 Express that is shown in the factory service manual, it gets obvious. Trim height is actually measured at the suspension so is a bit more accurate than the wheel well measurement, but the relate very well. If the van is at 35.5" at the wheelwell, you would be right at desired ride height for the van per the factory as that is what it measures when the trim height measures right.


The OP measures 33.75" so is not quite 2" low, which is what most of us were, but he is also under the max front weight by more than most of us, so that would explain it.


IMO, the OP is heading very well in the right direction for substantial improvements in several areas.
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Old 08-02-2018, 07:15 PM   #10
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Some current pricing as a guideline:

2 Moog coils $200
Air Lift Ultimate kit $350
4 Bilstein shocks $ 400
Ron paid $510 labor last month to have all of the above installed.

Air Lift compressor kits range in price from $200 to $430. $430 gets you a heavy duty dual path wireless system.

The Hellwig Anti-Sway Bar is going for $365 and the Roadmaster Anti-Sway Bar would be around $700 including the extra parts needed for a 2004 Chevy van.

It's not inexpensive for sure but if you split it as part maintenance (shocks & some labor) and part upgrades (2" lift) then maybe it is easier to justify doing it all.

And a note:

You could get some campsite leveling using the rear air bag system but it wouldn't work in all situations. You'd wouldn't be able to do away with your current leveling system.
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Old 08-02-2018, 09:05 PM   #11
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If you measure the "trim" height for a 3500 Express that is shown in the factory service manual, it gets obvious. Trim height is actually measured at the suspension so is a bit more accurate than the wheel well measurement, but the relate very well. If the van is at 35.5" at the wheelwell, you would be right at desired ride height for the van per the factory as that is what it measures when the trim height measures right.


The OP measures 33.75" so is not quite 2" low, which is what most of us were, but he is also under the max front weight by more than most of us, so that would explain it.
So, would it be true to say if I added a 2" lift to my Avenue, I would just be restoring it to it's approximate original ride height for the 3500 chassis?

I don't really like the idea of "lifting" my RV due to possible negative handling characteristics. But others have reported satisfaction with their lifts with no mention of negatives. Like the OP, I wouldn't mind the extra height for ground clearance.
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Old 08-02-2018, 09:11 PM   #12
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So, would it be true to say if I added a 2" lift to my Avenue, I would just be restoring it to it's approximate original ride height for the 3500 chassis?

I don't really like the idea of "lifting" my RV due to possible negative handling characteristics. But others have reported satisfaction with their lifts with no mention of negatives. Like the OP, I wouldn't mind the extra height for ground clearance.

Yes, that is exactly what we have been saying. If you have about 33.5" at the wheelwells on stock tire size, you are about 2" lower than recommended ride height. Going up that 2" would put all the suspension and steering parts in their optimum position geometry. Essentially everyone who has gone up the 2" say their van handles noticeably better after the height increase than before, and that is even without adding the rear swaybar. Add the rear swaybar and you will see a significant improvement in wind stability and wandering.
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Old 08-02-2018, 09:24 PM   #13
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Thanks very much for the sage advice and comments.

I have ordered the Moog Coils, 4 Bilsteins and the AirLift bags with the internal bump stop. I also got the Wireless remote on board compressor. It’s a bit of a luxury item but i do want to be able to get some minimal leveling with it so convenience is important.

I think I will hold off on the sway bar. I can add this later and I would like to see how it does.

I’ll let you know how it all turns out.

Next step is to find someone to install all this stuff!
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Old 08-02-2018, 09:56 PM   #14
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If I was doing it again I'd most likely hold off on the anti-sway bar and see how all the other stuff works first like what you're doing now.

I did it in two stages, shocks & anti-sway bar first for improved handling then new fronts coils and rear air bags later.
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Old 08-02-2018, 10:09 PM   #15
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Thanks very much for the sage advice and comments.

I have ordered the Moog Coils, 4 Bilsteins and the AirLift bags with the internal bump stop. I also got the Wireless remote on board compressor. Itís a bit of a luxury item but i do want to be able to get some minimal leveling with it so convenience is important.

I think I will hold off on the sway bar. I can add this later and I would like to see how it does.

Iíll let you know how it all turns out.

Next step is to find someone to install all this stuff!

Going in stages is certainly a good idea, and it will give you and all of us an better idea of which upgrades help which issues, and how much.



When you go looking for a place to put them in, a truck place is normally best, but the front springs do not need a compressor to be put in, so most anyone could do it if they know how. It is easier and safer with a compressor, however.
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Old 08-03-2018, 03:18 PM   #16
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Getting it up is the biggest thing right now, the handling is crap but tearing out the plumbing is what worries me.

I was wondering if putting a helper spring in the back would enable me to get more lift from the bags by giving them a higher starting point? The helper springs would bring it up a couple of inches and then the airbags could take it up further. My idea is that I would use the helper springs to get it up, and then use the airbags to get it way up. In the back I donít have steering geometry to worry about.

But I donít know if that would work out. If the problem point really is the waste water dump thatís pretty far forward.
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Old 08-03-2018, 03:31 PM   #17
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The air bags alone can support all of the sprung weight at the rear of your RT. I can't see how you'd get any additional height with additional springs (in addition to the helper air bags).

As you increase the psi in the bags the ride will get stiffer, even bouncing in the rear.

I like the psi set so that the floor of the van is level front to back.
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Old 08-03-2018, 06:11 PM   #18
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Getting it up is the biggest thing right now, the handling is crap but tearing out the plumbing is what worries me.

I was wondering if putting a helper spring in the back would enable me to get more lift from the bags by giving them a higher starting point? The helper springs would bring it up a couple of inches and then the airbags could take it up further. My idea is that I would use the helper springs to get it up, and then use the airbags to get it way up. In the back I donít have steering geometry to worry about.

But I donít know if that would work out. If the problem point really is the waste water dump thatís pretty far forward.



If you want the back higher, which IMO is not needed, springs would not be the first choice as it would get hugely too stiff in the rear. I have actually taken the overload leafs out of our rear springs to make it softer, and the airbags still take it to the same height.


To go higher you would want to use blocks, and you would also need longer shocks and you would always have more issues getting level to camp or even stopping if you have an absorption frig. Raising the rear only gains you 1/2 of the rear lift or less where it is needed at the valves.


It is a common error to think rear changes in height don't affect steering geometry in the front, as changing the height of either end will change the caster angles in the front. IIRC, when I trigged it out, you lose about 1/4* of positive caster for every 1" higher in the rear only you raise. Since you want as much caster as you can get, I would not put it as a great choice.


You can get 1/2" of extra ride height by going to the larger tires/wheels at 265-75-16.
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Old 08-04-2018, 04:33 AM   #19
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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.
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Old 08-04-2018, 12:00 PM   #20
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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.

Same here, just new front Bilstein struts at about 45,000 miles and now at 106,000 miles the Expresss van seems happy as is along with me.

I might be afraid to drive booster's Express Van, learning the truth about how poorly mine rides, handles..

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