Tag axle pressure

[Ivylog]

X2 on full fuel and water tank plus I go 5 psi over the tables as when the horse is headed to the barn, it makes no difference how strong the crosswinds are… big difference in tire temps on each side.

[Frank McElroy]

For 30+ years, my standard practice has been full fuel, full propane, full fresh water, empty holding tanks, full cargo as ready for travel, both passengers (we travel wife and I) and then tire pressure chart based on axle scale weight +5 psi.  I track tire pressures and see almost no difference side to side.  Lower left is my graph of tire pressures for the trip.  Real time tire pressures are on the lower right.

[KevinG]

Frank, What is that setup you are using to monitor everything? Do you have pressure sensors in on the air bags so you can monitor axle loads in real time?

[Frank McElroy]

8 minutes ago, KevinG said:

Frank, What is that setup you are using to monitor everything? Do you have pressure sensors in on the air bags so you can monitor axle loads in real time?

Those are tire pressures all displayed on one screen in real time.  I thought about a project to add pressure monitors on the lines of the ride height valve outputs to monitor changes in axle weights but it hasn't yet got up to the top of my to-do list.

The upper part of the screen is a SilverLeaf display that a lot of folks use. The reason why transmission data isn't shown is because in 2008 the Allison only transmitted data on J1939 and SilverLeaf doesn't read that format.  Another to-do list item to fix.  If anyone is interested in my display format send me an offline message and I'll send a copy of SilverLeaf scr file. 

The bottom portion uses a pressure pro tire monitoring system that SilverLeaf would use to display tire pressures.  However, the display is a custom program written by Bill Groves (RIP) and myself.  Tire pressures are color coded - green within range, grey signal lost, red out of range.  Numbers are the actual pressures numbers also shown inside the color coded boxes.

The display is on a dedicated tablet.  The usb port is used to keep the battery charged.  Because there is only one USB port, I converted both the old SilverLeaf RS-232 module and the USB pressure pro interface module to Bluetooth.  Pairing both to the tablet got around the limitation of only one USB port.

I like the setup with all the info I need in one location right next to my GPS display.  As I climb grades I like monitoring the load and power graphics along with boost pressure.  With this setup, I rarely look at my dash gauges.

[Melvin]

I most always have a Tahoe as a toad behind me. We had just finished with major repairs in the engine compartment one of the regulators we updated was for the tag axle. We thought we had set the pressure at 35 psi. With the generator, fuel tank and propane tank all riding on the front axle she felt really heavy that day. We blew the front drives steer tire off the rim at 70 mph, they were new tires with less than 5,000 miles. the only thing we could determine for the failure was my tag axle pressure changed to over 65 psi overloading the front axle. The tag axle is there to help stabilize your ride and carry some of the weight of the engine and to help when you may have a heavy trailer tonge weight. 

If you don't have accuses to a scale, you can pull measurements on level ground from the frame to the ground to check if your ride height is level. If the tail of your coach is too high, it will cause your toad to ride nose high wearing out the suspension and tires. 

I saw another comment about running different air pressures in your tires for a better ride or softer ride. I run 110 psi year-round the air ride system will manage your comfort and stability of the coach. if you run loaded tires to low on-air pressure, they will build heat and fail. In the old days we would adjust air pressures because of the steel coil suspension like in our old Gas Class A's that had the P-30 cassis. 

Buy the way it was the Monaco air ride suspension that keep the coach upright after losing the steer tire that day it automatically tries to balance the coach while in turns to prevent the coach from swaying and leaning into turns. We just held her straight down the road until she slowed down enough to pull off the road.

 

Edited February 25, 2023 by Melvin

[96 EVO]

Yeah, that air pressure regulator is pretty sensitive.

After an adjustment I raise and lower the tag a few times and re-check. Also have another look at the first opportunity after running down the road.

[96 EVO]

On 2/23/2023 at 8:57 PM, Frank McElroy said:

For 30+ years, my standard practice has been full fuel, full propane, full fresh water, empty holding tanks, full cargo as ready for travel, both passengers (we travel wife and I) and then tire pressure chart based on axle scale weight +5 psi.  I track tire pressures and see almost no difference side to side.  Lower left is my graph of tire pressures for the trip.  Real time tire pressures are on the lower right.

How did you manage to get your engine coolant to 185F, and your tranny at 0F 🤔?

Forget it. Just read your post regarding trans communication!

Edited February 25, 2023 by 96 EVO

[Frank McElroy]

9 minutes ago, 96 EVO said:

How did you manage to get your engine coolant to 185F, and your tranny at 0F 🤔?

Forget it. Just read your post regarding trans communication!

In the post above I explained it.  For a few years starting around early 2007 production, Monaco programmed the Allison transmission to only send data on the J1939 databus and not on the J1708 databus.  The engine communicates on both the faster J1939 and the slower J1708.  My older SilverLeaf module only communicated on the J1708 databus.  I think they now offer an interface module for the J1939 databus so I guess after 14 years maybe it's time for an upgrade.

[Ivylog]

Fortunately my tag’s regulator went to over 100 psi on a rainy day. Noticed that the compressor was cycling more often and that the psi in the tag tires had increased more than normal… didn’t have  temps. Stopped and could hear the regulator leaking and the gauge about maxed out. Cycled the knob back and forth and finally got it back to the 45 psi I use. Have no idea why and that was 10+ years ago… never messed up again.

[96 EVO]

3 minutes ago, Frank McElroy said:

In the post above I explained it.  For a few years starting around early 2007 production, Monaco programmed the Allison transmission to only send data on the J1939 databus and not on the J1708 databus.  The engine communicates on both the faster J1939 and the slower J1708.  My older SilverLeaf module only communicated on the J1708 databus.  I think they now offer an interface module for the J1939 databus so I guess after 14 years maybe it's time for an upgrade.

Is your speedo the same as mine...... can get digital trans temp to display where odo normally is?

[Frank McElroy]

32 minutes ago, 96 EVO said:

Is your speedo the same as mine...... can get digital trans temp to display where odo normally is?

Here is a wider shot climbing a grade showing my gauge cluster.  Below the speedometer is an lcd screen that can read out engine, transmission and digital air pressures in the primary and secondary air tanks.  I also have an Aladdin system that has all that data but I typically leave that screen on the rear view camera to watch the toad.  I like having the SilverLeaf, tire pressures, GPS, and rear view camera all clustered together.

 

[96 EVO]

Nice!

I don't have that, but can change my odometer to trans temp.

[Frank McElroy]

2 minutes ago, 96 EVO said:

Nice!

I don't have that, but can change my odometer to trans temp.

Just to the left of the speedometer I have the fuel, trans, engine, and coolant temp gauges clustered together.  I also have alert alarms set on my Aladdin to chime if any one of those temps get above limits I preset in the Aladdin alarm settings.