P30 P32 Drivability Handling Upgrades Information Collection

[eXodus]

There are ton of upgrades and adjustments we can do to make the P30 handle better. This threat is meant to collect all those and rank them in a order of effectiveness or cost?

Rank	Description of the upgrade	Effectiveness	Cost
1.	Grease front end	not much	$
2.	Tighten Steeringbox	low-medium	free
3.	Weight coach for front Airbag adjustment	medium	$
4.	Alignment	medium-large	$$$
5.	Swaybar bushings	medium	$$
6.	Shock absorbers	medium-large	$$
7.	Super Steer Driver Bellcrank	large	$$$
7.	Super Steer passenger Bellcrank	low	$$$
8.	SumoSprings Rear	high	$$
9.	Airbags Rear	medium	$$$
10.	Trackbar Rear	high	$$$

Let me know what you think and throw in all the Drivability tips you have for the P30 P32s and how we can rank them for newcomers. This is my initial shot at this - I'm happy to change columns cost - effectiveness etc.

[udidwht]

As for the air bag pressure/s on the front the GM manual from motorhome states minimum should be maintained between 10psi and max 50psi for 4,300lb front, 40psi min and 50psi max for 5,000lb front and 60psi min and 100psi max for 5,500lb front.

However the manual from the Airlift bags (81560) states...

Motorhomes/Commercial chassis:

40psi min and 90psi max

ALTHOUGH THE AIR SPRINGS ARE RATED AT A MAXIMUM INFLATION PRESSURE OF
90 PSI (6.2BAR) FOR MOTORHOMES AND COMMERCIAL CHASSIS, 50 PSI (3.5BAR)
FOR TRUCKS AND PASSENGER VANS, THE AIR PRESSURE ACTUALLY NEEDED IS
DEPENDENT ON LOAD AND GROSS VEHICLE WEIGHT RATING.

FAILURE TO MAINTAIN CORRECT MINIMUM PRESSURE (OR PRESSURE
PROPORTIONAL TO LOAD), BOTTOMING OUT, OVER-EXTENSION OR RUBBING
AGAINST ANOTHER COMPONENT WILL VOID THE WARRANTY.

The min/max recommended via Airlift manual differs compared to the GM manual. Any of you still just using the min/max GM recommendation vs Airlfit min/max? Can't see why continuing to follow those GM amount/s (especially min) would cause any issue.

[eXodus]

My 4300 lbs front end rides super hard at 40psi and sits very tall.
I like it at 35psi there it is level and firm, at 30 psi it gets really comfortable. Below 25 it starts getting wonky. 

When you read the airlift manual exactly,
It states either minimum pressure or pressure proportional to weight. So on a lighter rig you don't need to run their pressure recommendations

there is also the other method of adjusting air bag pressure, via distance from the lower control arm bump stop to the upper frame.
Not sure which to trust.

[jspringator]

I've done all of those things that apply to my coach, and more (replaced front airbags with weight appropriate springs) but one thing that really helped was lowering the air pressure to 5 psi below placard pressures based on the actual weight of the coach.  I also made an effort to lighten the coach behind the rear axle.  I removed the spare (controversial, I know), got a lighter mattress, and moved everything I could forward. I've resigned myself to the fact that this coach was designed to operate at 60 mph +-, so I set the cruise at 62 and go.

[eXodus]

Mine likes 63mph 

At 65 it starts shift down a lot at the slightest incline and I don't like the noise.

[udidwht]

My 4300 lbs front end rides super hard at 40psi and sits very tall.
I like it at 35psi there it is level and firm, at 30 psi it gets really comfortable. Below 25 it starts getting wonky. 

When you read the airlift manual exactly,
It states either minimum pressure or pressure proportional to weight. So on a lighter rig you don't need to run their pressure recommendations

there is also the other method of adjusting air bag pressure, via distance from the lower control arm bump stop to the upper frame.
Not sure which to trust.

There is no specific measurement ones front should be. The measurement is used to set front end alignment degree setting and nothing else.


FRONT:


Coil springs sometimes break near the end and wedge in place without obvious indication of the
failure. Look hard. If you think this might have happened, the only way to prove it is to remove
the spring.
In the front, the measurement is checked on each side between the lower control arm rubber
bumper bracket and cross member flange. This measurement must be perpendicular to the cross
member flange. It is from "iron to iron". The rubber bumper is ignored. Look at the illustration
below.


Key here is that both sides of the front axle should be the same, and this measurement is used in
the CASTER determination. The front air bags should be inflated to the recommended pressure
for your chassis. Don't attempt to raise or lower the chassis measurements using the air bags. (If
your motorhome has air bags that have been added to the rear to compensate for sagging
springs, make sure they are set to the pressure you plan on maintaining in them.)
Now, take that front measurement and find it in the top row of the chart below, then go down
to the "MOTOR HOME" row to get the degree setting. This is the initial point for the
CASTER setting. This chart is from the 1995 "Chevrolet Motor Home Chassis Service Guide"
for the P Chassis.


Note the various vehicles in the first column that use the P Chassis. Also note that there is a
separate line for the MOTOR HOME version. It is different from the "P-20, 30" line. There is a
distinct possibility that an alignment shop will use the incorrect numbers if you tell them to align
"my P30 chassis". But of course, we intend to TELL them the CASTER angle we want – once
we go through this entire process


http://truckroadservice.com/barth_attachments/P-Chassis-AlignmentProcess.pdf