Hydraulic vs. Air Ride Suspension (ie. Liquid Spring vs. Kelderman)

[ReluctantTraveler]

I've seen some past discussions on here about a hydraulic suspension system upgrade vs. air ride (as in, a product like Liquid Spring vs. what Kelderman offers) to soften the ride and improve handling on F-550/5500 trucks.

It's been a while since the last one was posted, and I'm curious if anyone has any updated thoughts.

Have you considered one or the other (or both)? What did you decide and why? Is one option better than the other for mostly domestic travel that does NOT involve extreme off-roading?

Just to head this off early: "just use blocks to level" or "big trucks ride rough deal with it" is not the conversation I'm interested in having. I specifically want to compare the two systems on things like reliability and performance as I think about which I'd install in my build.

Thanks in advance!

UPDATE FOR CLARITY:
1. I will NOT be doing heavy off-roading.
2. I'm as concerned with unloaded ride quality as I am with a rig on the flatbed.

 

[BikePilot]

I've never heard of a hydraulic spring, but all go-fast off road vehicles I've messed with (bikes, buggies, trophy trucks) have steel springs and sophisticated damping (hydraulic--maybe that's what you mean?).

I've also not messed with 5500s. For a 3500 Ram Carli and Thuren offer many options that work amazingly well. I have a pretty modest Thuren setup on my 3500 and it rides really well. It's all about getting the right travel, spring rate, and damping control for your weight and use profile.

Good luck!

 

[danneskjold]

I think objectively Liquid Spring is going to offer better performance than something like a Kelderman system but at double the cost ($25k for LS) and reduced reliability. There are a lot of different pieces to fail on a LS, and few of them are serviceable by the end user. I was reading on IG the other day about a guy with LS on an F550 in Alaska and he is dealing with some really bad software issues. Even if something like a hydraulic fitting fails you can't just get a new part or hydraulic fluid at a local NAPA. That is one thing if you are in a Class A RV, an ambulance or even a brush truck - but if you're in an "expedition vehicle" that is a lot more problematic.

On the flip side, on something like a Kelderman if something like an air line, fitting, or bag fails that is pretty easy to fix and get yourself back on the road.

Also, controversial opinion - I think air ride is a great option for vehicles that have variable weights or need to drop the back end (ambulances) but for the price of a Kelderman ($5-6k + install) you could get custom made leaf packs and shocks and be within spitting distance of the ride comfort I think. You also have the added benefit of the reliability and suspension travel of leaf springs and at the end of the day how fast off road do you really want to drive your 18k lbs F550?

 

[ReluctantTraveler]

I think objectively Liquid Spring is going to offer better performance than something like a Kelderman system but at double the cost ($25k for LS) and reduced reliability. There are a lot of different pieces to fail on a LS, and few of them are serviceable by the end user. I was reading on IG the other day about a guy with LS on an F550 in Alaska and he is dealing with some really bad software issues. Even if something like a hydraulic fitting fails you can't just get a new part or hydraulic fluid at a local NAPA. That is one thing if you are in a Class A RV, an ambulance or even a brush truck - but if you're in an "expedition vehicle" that is a lot more problematic.

On the flip side, on something like a Kelderman if something like an air line, fitting, or bag fails that is pretty easy to fix and get yourself back on the road.

Thanks, that was exactly the kind of analysis I was looking for. Much appreciated!

 

[ReluctantTraveler]

Also, controversial opinion - I think air ride is a great option for vehicles that have variable weights or need to drop the back end (ambulances) but for the price of a Kelderman ($5-6k + install) you could get custom made leaf packs and shocks and be within spitting distance of the ride comfort I think. You also have the added benefit of the reliability and suspension travel of leaf springs and at the end of the day how fast off road do you really want to drive your 18k lbs F550?

Oh, also, just to reiterate, this is NOT for a vehicle intended for heavy "expedition" or off-road use. Lots of highway travel, service roads and the like.

At least some of the time it will be driven fully unloaded, and the upgraded suspension also doubles as a leveling setup.

 

[LikeABoss]

I just installed keldermans 2 stage rear on my ram 4500. I’ve only driven about 100 miles with it (unloaded) as I’m working on the front end now. It makes a big difference. It rides a bit worse than my 3/4 ton did but not dramatically and nothing like it was before. I think when I get rid of the 19.5 wheels it will be down right comfortable.

I was not interested in the liquid spring due to cost and complexity. I would have sprung for the kelderman 4 link but was really interested in the simplicity of the 2 stage. I could limp out of the backcountry with a blown bag fairly easily. When I talked to kelderman they said the ride was about the same between the two, the 4 link is just more adjustable.

Keldermans instructions are well documented to be terrible but this was so easy you barely need them (the what goes where part, not getting nuts and bolts in and out between the fuel tank and frame). They did send me a bunch of coarse thread bolts with fine nuts and vice versa which was super annoying. There are about 10 different size bolts and they managed to make hardly any match. Also they said the main shackle bolt was 5/8 (and that’s what they sent) but it is 3/4.

Based on the unloaded ride I would definitely take the time to do again.

 

[andy_b]

I've seen some past discussions on here about a hydraulic suspension system upgrade vs. air ride (as in, a product like Liquid Spring vs. what Kelderman offers) to soften the ride and improve handling on F-550/5500 trucks.

It's been a while since the last one was posted, and I'm curious if anyone has any updated thoughts.

Have you considered one or the other (or both)? What did you decide and why? Is one option better than the other for mostly domestic travel that does NOT involve extreme off-roading?

Just to head this off early: "just use blocks to level" or "big trucks ride rough deal with it" is not the conversation I'm interested in having. I specifically want to compare the two systems on things like reliability and performance as I think about which I'd install in my build.

Thanks in advance!

I have ridden in 550/5500 series trucks with Liquid Spring or air ride suspension. They both are similar in ride quality and not as smooth as you'd imagine (esp for the cost and complexity). As others have mentioned, the adjustable nature is helpful for things like loading ambulances or variable weights. Also, the difference in the various Liquid Spring settings is quite noticeable but the firmest setting is definitely not "sporting" and the softest setting is not that plush.

Custom leafs and shocks would be much less expensive, less complex and probably better riding for an application such as an RV with a relatively fixed weight range. Don't forget that in addition to the cost of the air or hydraulic spring package, you will also have to upgrade the damping system for maximum benefit.

The Kelderman is more user serviceable (and as a consequence, more reliable since it is unlikely to leave you stranded in a failure). Neither are as reliable as custom leafs and shocks.

 

[zb39]

I have had my 4 link Kelderman for 3 years and 31K miles now. I also did the front at the same time. Night and day difference in ride when empty. Much much better riding when loaded also. ZERO issues to date. Not cheap, but I love it.
Levelling at camp site is awesome. Lowering truck when loading cascade or anything is nice. Best mod ever for me.

 

[ReluctantTraveler]

I have had my 4 link Kelderman for 3 years and 31K miles now. I also did the front at the same time. Night and day difference in ride when empty. Much much better riding when loaded also. ZERO issues to date. Not cheap, but I love it.
Levelling at camp site is awesome. Lowering truck when loading cascade or anything is nice. Best mod ever for me.

Thanks!

Question about "camp mode." When used for camp leveling, do they have any give to them, or do they lock into that position fully?

I'm wondering if you still get rocking like on a boat, or if it's more like having a trailer with stabilizer jacks down.