59 replies to this topic

[ntsqd]

With something like a Bilstein 7100 series damper you can change the shim stack to change the valving.  I had to do this on the rear of my '84 Xcab when I swapped to 63" long GM 3/4t rear springs. Not because of a different spring rate, but because those springs have enough less internal friction to show up in the overall damping. Numerically the change wasn't much, from 255/70 shims to 278/75 shims but the difference in how the truck behaved was noticeable. These numbers are the force in Newtons need to move the shaft at one particular shock shaft velocity. Rebound first, Compression second.

 

With two different spring types, say leafs and air, you'll never get the damping very close. Each type of spring has unique needs in damping. As an example, in the 7100 series the std. off the shelf shim stack for leaf springs is 255/70. The std. off the shelf shim stack for coil springs is 360/80. One shim stack that I've seen for torsion bars was 345/135. I've no idea what air springs would want to start at, but I'd guess something close to coil springs. None other than Brett King, of King Shocks, told a good friend and savvy suspension tuner not to combine different spring types as he'd never make it work well in a serious Pre-runner style truck.

 

That said, I doubt many will want to abuse their campers hard enough to need that tight of a suspension tune.

 

I've seen air springs fail off road. I've seen them live and excel off road. It's dependent on the whole package; how are they driven, how were they installed, where were they installed (on the vehicle and by whom), what quality were they to start with, what kind of maintenance have they received since.

[Vic Harder]

Good to know about not mixing spring types.  And about the flexibility of the 7100 series shocks.  Thanks!

[sourdough]

This is out of character for me but I feel must chime in here and respectfully disagree after reading three posts bashing airbags.

 

I've been running Firestone Ride Rites for nearly a decade now as have many others without incident. I have not driven conservatively with them and have put them through about as extreme abuse one could expect with a camper on a vehicle without issue. I'm sorry, but I feel it is disingenuous to scare away newbies asking questions from using something that is actually quite capable. In short, airbags are not too fragile for off-roading.

Coincidentally a friend of mine and WTW member bought your old airbags when you sold them. It is our novice opinion that the cradles you installed with yours were the cause of your problems and actually pinched the airbag, just my opinion. Anyway, enjoy the new rig.

  Pinching is a design flaw, now corrected on new units with internal bump stops that prevent pinching. Cradles where not the cause.  No air in the rubber air bladder was the cause. Rubber airbags are fragile IMHO. And there are too many tubing connections and little hoses for air leaks. BTDT, give me spring steel.

 Disingenuous, B.S. about what. I sold the bags, hoses,cradles and hardware for $60. I told you one was holed and needed replacement. There was no discussion about  cause or effect. You think airbags are great, I do not.  We all have opinions. How does any of this make me disingenuous.

Edited by sourdough, 13 August 2016 - 04:05 PM.

[moveinon]

There continues to be discussion on here about whether airbags are weak as though it was just differing opinion.  I have run air bags on a very modified off road truck that put on many miles in very tough situations without problems as well as my current Taco and camper without problems.  If you do your homework on durability of air bags you will see that more than one car that has won the baja 1000 ran air bags.  They obviously had a lot of suspension modifications like empi coilovers and other changes, but the durability of airbags is race proven -not just opinion.  They also have air bag suspension built into a lot of sand rails and other dedicated off road rigs.  And these are used for jumping, sometimes with a separate reservoir to reduce rebound.  Tractor trailers run airbags all the time, so do dump trucks.  These uses carry way more weight and get punished more than any camper and truck could withstand and they hold up.  The bags are made by the same manufacturers that produce them for our trucks.  In these uses failure is so small it is basically nonexistent.  The issue with air bags is to purchase a quality bag and install it properly with quality air lines and fittings, which is very easy to do.  If that it done they do not fail, if not they will leak or leak and fail.

[sourdough]

There continues to be discussion on here about whether airbags are weak as though it was just differing opinion.  I have run air bags on a very modified off road truck that put on many miles in very tough situations without problems as well as my current Taco and camper without problems.  If you do your homework on durability of air bags you will see that more than one car that has won the baja 1000 ran air bags.  They obviously had a lot of suspension modifications like empi coilovers and other changes, but the durability of airbags is race proven -not just opinion.  They also have air bag suspension built into a lot of sand rails and other dedicated off road rigs.  And these are used for jumping, sometimes with a separate reservoir to reduce rebound.  Tractor trailers run airbags all the time, so do dump trucks.  These uses carry way more weight and get punished more than any camper and truck could withstand and they hold up.  The bags are made by the same manufacturers that produce them for our trucks.  In these uses failure is so small it is basically nonexistent.  The issue with air bags is to purchase a quality bag and install it properly with quality air lines and fittings, which is very easy to do.  If that it done they do not fail, if not they will leak or leak and fail.

 I don't believe a modified race trunk or a sand buggy set up for jumping or a 18 wheeler has any relevance just because they have air bags. Comparing there mounting systems to an overloaded stock truck and camper running a universal bolt on over the counter air bag kit is wrong.

I totally agree with, when bag leaks they can and do fail. The bag is tough, the supporting hardware not so much. They now have an internal bumpstop that keeps the bags from over compressing due to low or lost air.

 A race truck, sand buggy or 18 wheelers are set up with a external bump stop factoring in bag compression before total air bag compression and pinching.

This thread is not talking about anything but over the counter universal air bag kits. It is the supporting hardware and hoses in the over the counter kits that are fragile and cause the bag to fail. 

My properly installed over the counter stock kit failed. The failure left me limping 40+ miles to get repairs only to find it would be days out for a replacement bag. I had the bags and all the hoses and hardware pulled and replaced with steel springs. I sold the camper and kept the spring kit http://www.activesuspension.com  It works like a sway bar also. 

Edited by sourdough, 13 August 2016 - 11:30 PM.

[ntsqd]

I think their other uses are relevant. It shows that they work and live in situations that get worked hard. The air spring doesn't know if it's being compressed by a jump landing or because it's under an 80k lbs OTR truck. I would go further to say that the jump landing is more strenuous to the air spring than anything a truck with a camper will ever put one through.

 

No experience, so no comment directly on the mounting systems. From experience I will say that it is easy to design things that appear to be robust enough for the application and should be based on similar experiences, but reality proves different from what was expected and the design is a failure. The need for an internal bump-stop shows that the bracket system wasn't designed well. A good design would have used the OEM bump-stop and avoided being pinched even when that was metal to metal.

 

Maybe you're not talking about hoses & fittings other than supplied, but as a designer who first was working with hydraulics and now with pneumatics (not to mention race vehicle plumbing) I would be VERY disinclined to use anything supplied in a kit if if it were not up to industrial/production part standards.

 

All of that said I'm not a fan of air springs being used full time to supplement a leaf spring suspension. Each type of spring has it's own unique damping needs. Mixing types in on suspension means that the damping curve will never, ever be right. Maybe a truck with a camper will never be pushed hard enough to need damping that well tuned, but I still find it offensive and will resist doing it if at all possible.

 

The same can be said for that add-on coil spring system. I think that it is an abomination. It puts loads in parts never designed to be loaded that way, and it can not add roll stiffness (sway-bar) only spring rate. For the cost of that system and it's install the rear leaves could have been rebuilt or replaced with leaf springs designed for the job. Deaver, Alcan, and Valley are at least 3 names that can perform this work.

Edited by ntsqd, 14 August 2016 - 03:48 PM.

[SunMan]

Pinching is a design flaw, now corrected on new units with internal bump stops that prevent pinching. Cradles where not the cause.  No air in the rubber air bladder was the cause. Rubber airbags are fragile IMHO. And there are too many tubing connections and little hoses for air leaks. BTDT, give me spring steel.
 Disingenuous, B.S. about what. I sold the bags, hoses,cradles and hardware for $60. I told you one was holed and needed replacement. There was no discussion about  cause or effect. You think airbags are great, I do not.  We all have opinions. How does any of this make me disingenuous.

Not implying there was anything shady about the sale, my friend wanted the hardware only, he knew what he was buying, the one good airbag was a bonus as he has a spare if he ever needs it. He ended up selling the cradles.

All I am saying is that you telling a newbie asking questions that airbags are fragile and not suitable for off-road is simply not true. I would hazard a guess that the majority of people on this forum have airbags and use them off-road. I'm sorry you had a bad experience with your bags but that does not mean they are fragile. Everyone needs to make their own decisions as to what best suits their needs, for myself and many others, airbags fit that requirement.

[sourdough]

After market air bag kits sold over the counter are fragile and not designed for off-road use. Custom off-road air bag suspension systems are  designed for off-road use. 

Roadster Active Suspension reviews....https://www.google.c...spension review

Edited by sourdough, 14 August 2016 - 05:16 PM.

[RockCod]

Thanks to everyone for the options and contributions to this thread. My timing allows me to figure out suspension needs first and this sure helps.

[sourdough]

A truck loaded over it's rated GVW will never be safe just installing an aftermarket spring helper. Be it air bags or overload springs. 

Statement below is from here....http://riderite.com/... Product Detail

 

Ride-Rite air helper springs enhance the ride by reducing inter-leaf friction. Please remember that air springs do not increase the loadcarrying capacity of your vehicle. *DO NOT EXCEED THE VEHICLE’S RECOMMENDED GROSS VEHICLE WEIGHT RATING (GVWR

 

What Is Covered:

 This warranty does not apply to Ride Rite Air Spring Assemblies that have been improperly applied, improperly installed, used in racing or off road applications or used for commercial purposes. 
 

Edited by sourdough, 14 August 2016 - 07:32 PM.