Lazy Daze Owners' Group

I have a 2011 31 TB with Steer Safe and rear sway bars.  It's not bad...but it ain't GOOD either.  Eighteen Wheelers going buy at 70+ mph and crappy roads all over the midwest makes me long for something a little more comfy.  Fatigue and the white knuckle thing at the end of each day gets old.  Takes some of the pleasure out of the experience.

My 2016 MB handles reasonably well.   To add that much money, weight, and complexity to the equation does not pencil out.

Well folks, We've decided to bite the bullet and have the LiquidSpring suspension system installed on our 2011 31TB.  It can't happen until the the 3rd week in October.  They swear I won't believe how good it will ride and handle after.  I guess we shall see.  I will post a detailed review of the system after the install.  Looks like we will be the first LD they have installed it on. 

Well, I hope you don't mind me playing Devil's advocate and trying to point out why you should not install the LiquidSpring CLASS system. Of course, I have no dog in the fight so I can be entirely objective. I hope you take no offense - I am just offering my thoughts and would certainly be interested in hearing yours also

My initial thoughts is that this very expensive system is a solution in search of a problem. In some applications it may be more valuable than others and the reason I state that is because this upgrade is to the rear suspension only. For an RV the passengers should be seated over the front axle while driving and not the rear. For another application such as a Shuttle Bus where passengers will be seated directly over the rear axle they would receive the maximum benefit from any improvements to the rear axle.

Yes, a five-link suspension system (e.g. LiquidSpring CLASS) is an improvement when compared to a conventional leaf spring system but what exactly are those improvements? In short, you have the ability to tune the suspension to a great degree while leaf springs limit you severely. Range of motion is another area where a five-link trumps leafs. But are these an advantage for our purpose? I do not believe so. RVs do not find themselves on race courses on or off road. Even while on road in normal driving I am guessing most RV owners are very conservative drivers and show respect for the fact that their vehicles are far different from most others.

Now on to the spring and shock absorber combination. At first I though they may be making use of an interesting fluid I worked with two plus decades ago while working in the Lord Corporation High Energy Laboratory. That fluid was Magneto-Rheological (MR) fluid and was very cool stuff. You can read more about it here if you wish. From what I have gathered they are in fact using a compressible silicone fluid which is nothing special. Personally, I enjoy having the spring and shock absorber as independent components within a system. One may fail while the other is still able to work. Since the CLASS systems is placing all of their eggs in one basket - if one fails so does the other.

Now let's discuss the probability of failure. Leaf springs and shock absorbers are a very mature technology and there is a low probability of failure. If there is a problem you can most likely have it fixed anywhere. Now a five-link is a reasonably mature technology also but this one is highly customized - if you require replacement bushings or parts the only place you will find them is from the manufacturer. And when we discuss the most critical components of this system - the combination spring and shock absorber along with all of the associated sensors, 3,500 PSI system, computers and electromechanical components, etc. you are really increasing both the probability and severity of having a problem. When compared to leafs springs and shock absorbers this is one heck of a mess!

Installation is another issue. I took a look at the instructions there are some specialized tools and procedures required. A 600 ft-lb torque wrench is an $800-900 tool that you simply do not find in most garages. Then again, if you are torquing the main nuts and bolts which hold my control arms to the brackets and they call for 600 ft-lbs I expect that tool to be used. And how about a magnetic frame drill for drilling the holes that some of the mounting holes for the brackets? Those are $600-800 also and to be honest I have never seen one in an automotive shop. And if it were my choice I would prefer those holes to be drilled in the factory during assembly of the vehicle and not in a garage after. I'll vote for the million dollar FANUC robot drilling those critical holes in a controlled environment versus a magnetic frame drill that "looks good to me."

I could go on about the anti-squat advantage of a five-link while countering it with a discussion on the change in thrust angle as a result of the Panhard rod moving the axle laterally while the suspension compresses or extends. Of course the length of the Panhard rod relative to the suspension travel defines just how much lateral movement of the axle there is. In this case the rod is very short although the amount of suspension travel may be minimal also. Some things look real good on paper and even sound nice when talked about. But in real life they just do not return the expected value. Or worse yet, they transform a simple and very reliable system into something that unnecessarily complex and not nearly as reliable.

You are familiar with The Pareto principle? Sometimes called the 80/20 rule. In this case I strongly believe you could spend 20% of the cost of the CLASS and reward yourself with 80% of the improvement. The icing on the cake is that the system is just as reliable and remains simple and easy to maintain.

Maybe Koni FSDs in all four corners, upgraded front and rear anti-swar bars with appropriate bushings and possibly a HD steering damper up front and bolt-on track bar assembly for the rear? Again, you will be spending most of your time up front while underway so how beneficial will it be to upgrade only the rear?

Hope you enjoyed my thoughts and don't take any offense. I am just exercising my mind on a wild and crazy Friday night

Curious.
How much does this system weigh vs how much excess CCC do you have on your 31’ LD with Big Foot levelers ?
Had it weighed ‘trip ready’ recently?