2018 Spartan Shocks

[ARD]

Originally Posted by Stuart W

Ok here is the actual data on ride height, the tolerance is 1/8 inch +/- and 1/8 Side to Side

All of this information is so way over my head. I can't wait to take the Spartan class in September. I can tell you all that Spartan had Cummins made the following adjustments on my coach if it helps any:

1. Front ride height was 9.14 left and right and was adjusted to 9.25.

2.Rear was at 20.5 from center bolt to center bolt of shocks on drive axle and was adjusted to 20 inches.

[Stuart W]

Originally Posted by ARD

All of this information is so way over my head. I can't wait to take the Spartan class in September. I can tell you all that Spartan had Cummins made the following adjustments on my coach if it helps any:

1. Front ride height was 9.14 left and right and was adjusted to 9.25.

2.Rear was at 20.5 from center bolt to center bolt of shocks on drive axle and was adjusted to 20 inches.

Thank you, that is helpful information [emoji4]

[Sicduc]

Has anyone had a loud bang/bottoming out sound while bouncing?

[Dutch Star Don]

I know you guys are discussing the Spartan chassis, but I really disliked the ride quality of my Freightliner. I initially changed out all the shocks, tag too, to Koni FSD's. At that time (2014), Koni didn't offer an FSD for independent front suspension. Consequently, I installed the Koni Red and didn't see much of a difference. A year or so later, Koni finally came out with EVO shock for IFS front ends (at least Freightliner).

I bought a set of the EVO' s and felt I finally got some improvement. It eliminated a lot of that short chop I was getting that would make the windshield shade get bouncing. I also installed the airbag one way valves for the front end, from Source Engineering. I didn't see any real freeway improvement form them, but I was more after eliminating "elephant walk" in slow speed situations.

[irv1997]

Originally Posted by Sicduc

Has anyone had a loud bang/bottoming out sound while bouncing?

YES! Some bridge approaches have us bouncing like crazy and the bad ones we hear the loud bang like we can’t bounce any higher.

[10 fan]

Sounds like shocks reaching their limit.

[willipaul]

Originally Posted by Sicduc

Has anyone had a loud bang/bottoming out sound while bouncing?

yes, i get it as well....

[Stuart W]

According to Spartan, ride height is very critical, I posted the information earlier in this thread. My slides are out right now but when I close them I will check mine, they suggest the rears be set first then the fronts. The fronts are easy to measure the rears are challenging on the ground. The following comes from my Motorcycle knowledge: you want your shocks travel to be in the center of the range, example: if a shock has 4 inches of travel, you would want it to rest at 2 inch’s of the travel, if your air bags are over inflated raising the suspension so that now that same shock is sitting at one inch only 1 inch used or even worse your suspension is under inflated that same shock is sitting at 3 of the 4 inch’s of travel used, its going to bottom out fast, possibly making noise or damaging the shock itself. Remember shocks work both up and down, when the force is pushing down, they slow the motion of the suspension from bottoming, then when the suspension rebounds up, they slow the upward motion keeping the suspension from topping out. ARD reports that her rear airbags were set to high, she lost a rear shock, broke in two.

[Canuck53]

How is the ride height set and how does it get out of ideal setting? Sounds like it is something to dig into if you do a factory pickup.

[Stuart W]

Originally Posted by Canuck53

How is the ride height set and how does it get out of ideal setting? Sounds like it is something to dig into if you do a factory pickup.

If you look at the front airbags, you will see a valve and a rod in front of each airbag. This rod can be shortened or lengthened to inflate of deflate the air bag. This inflation sets the ride height. The back only has one valve that works both rear drive axle airbags.
So when you start the MH with the air dumped, the air bags fill up until these valves shut off the filling.


It is my understanding that Newmar checks the alignment of each coach after they are built and I would think ride height is set prior to alignment .
You have a great question, not sure what the answer is [emoji848]

[flyboy013]

Originally Posted by ARD

I can't wait to take the Spartan class in September.

Are you taking the Academy training the week of September 10th? If so, I’ll see you there.

[BBorgo]

Originally Posted by Stuart W

If you look at the front airbags, you will see a valve and a rod in front of each airbag. This rod can be shortened or lengthened to inflate of deflate the air bag. This inflation sets the ride height. The back only has one valve that works both rear drive axle airbags.
So when you start the MH with the air dumped, the air bags fill up until these valves shut off the filling.


It is my understanding that Newmar checks the alignment of each coach after they are built and I would think ride height is set prior to alignment .
You have a great question, not sure what the answer is [emoji848]

AFAIK the ride height is a function of the air suspension system. Alignment is a mechanical system. The ride height is possibly off on most delivered systems because the owner is going to load more weight or less weight onto their coach than the factory "guess". That is, the factory is going to make an educated guess at how much the new owner is going to load onto the coach and set the ride height accordingly.
If you want to get to the best possible chassis settings you'll have to load your coach with what possessions you will carry, load an average amount of fuel and water (probably half full each), have the coach corner weighed to get the correct tire pressure, then have the ride height set.
Spartan's 5 day Maintenance school does that, I would guess Freightliner does the same.

Bob

[ARD]

Originally Posted by flyboy013

Are you taking the Academy training the week of September 10th? If so, I’ll see you there.

Yes. Look forward to seeing you there. [emoji2]

[Stuart W]

Originally Posted by BBorgo

AFAIK the ride height is a function of the air suspension system. Alignment is a mechanical system. The ride height is possibly off on most delivered systems because the owner is going to load more weight or less weight onto their coach than the factory "guess". That is, the factory is going to make an educated guess at how much the new owner is going to load onto the coach and set the ride height accordingly.

If you want to get to the best possible chassis settings you'll have to load your coach with what possessions you will carry, load an average amount of fuel and water (probably half full each), have the coach corner weighed to get the correct tire pressure, then have the ride height set.

Spartan's 5 day Maintenance school does that, I would guess Freightliner does the same.



Bob

Bob, it is my understanding after talking with Spartan that at least on my DS, the ride height is measured buy the height of the installed front airbag and the length of the rear installed shocks. I asked the question to Spartan, how could it be off? Answer not set right or adjustment rod loose or defective failed part.
Help me with this, if you have a mechanical valve that when adjusted correctly shuts the air flow off to the airbag when it reaches 9.25 inches (it does not measure air pressure in the airbag) how would adding or subtracting coach weight change the ride height? For instance when my 150 gallon fuel thank (That primarily sits over my front airbags) is empty or full?. As the fuel empty’s the frontend gets lighter and attempts to rise up, the valve senses this and opens the valve to let air out of the Air bag until the lever stops at the correct pre determined length of the valve rod.