Need Help Setting Proper Tag Axle Down Air Pressure

[Czar Of Poop]

How do you determine the proper air pressure setting for the tag axle downward motion? When the coach is at travel mode and air ride at 100-125 psi, what should the tag axle meter be reading? I would like to understand this portion of the air system better. Thank You

[Twomed]

Most here run 42-45 psi on the adjustment gauge. Every coach will be different depending on loading and total weight. Mine runs with almost 6k on the tag, 19k on the drive, and 14k on front axle. Try to have the coach in whatever is a "normal" mode/load fr your use...water, fuel, stuff etc.


The only way to check is to run through the scales several times, or find a weigh service at a rally. You have to be able to spot the tag and drive on separate pads obviously. It's a trial and error thing until you get it right or get lucky. Make small adjustments and cycle the tag up/down and drive with tag down for at least 100 yards to get an accurate weigh after making a correction.

[K7JV]

I would love to hear a "right" answer. We have our tag on our '06 Countess III at 52 psi. That makes the loading on all six rear tires relatively equal, per tire. We carry 80 psi on those six tires, and had excellent wear for over 50,000 miles. We just did replace the tires due to age (9 years), when we replaced the front (Goodyear, due to the rivering that you may read a lot about) tires. Wear was not an issue on the rear tires, at all. There was some rounding on the tag tires due to scuffing in turns, but even that wear was not excessive.

Be careful, though. When you load the tag, you also load the front axle, and it is easy to load it beyond its rating.

We went thru a truck weigh scale in Idaho several times, and adjusted the tag after each weighing to settle on the 52 psi setting. With the coach full of fresh water, both holding tanks empty, the fuel tank full and the storage loaded for normal use, we ended up with 14,320 on the steer axle, 14,840 on the drive axle and 7,660 on the tag. We carry 115 psi on the steer tires and 80 psi (tire recommended minimum) on both rear axles.

If anyone has a definitive "right" answer, I'm all ears!

I will share that last winter, we got "stuck" in snow at Lages Junction in northern Nevada, in 6" of snow on top of a layer of ice. It never occurred to me to lift the tag to try to get back on the highway. I wound up disconnecting, finding a better spot with the car, retrieving the coach, reconnecting and taking a run at it to get back on the highway. Next time I'll try lifting the tag. Live and learn.

[Twomed]

"Right" answer is when you are within specs for axle weights and tire loadings....AND it handles well. I like the 14K or so weight for long day/trip travel...just feels "right" to me.


Trial and error for each coach. The gauges are not real high tech, the tag linkage varies to some extent by either cables or chain links. The important thing is proper weighing and being in specs for safety.


Jim if you lost a dual the remaining single and the tag on that side would be overloaded. Running 100 would be way safer and the ride will still feel the same IMHO.

[Czar Of Poop]

Thank you all for the info. We will find a scale and check our weights on the axles. Right now the meter reads 52psi at travel mode ready to roll down the highway. I keep 110psi in all tires at cold and it has a nice ride. The tires suggest 120psi at cold. Our coach weights 43,500 lbs.

[sknopster]

I'm curious if you were able to get a lighter front axle with a lower pressure setting on the tag axle. Your numbers work out perfectly, but if you could get away with less weight on the steer axle, it seems that a front blow-out is less likely and more controllable if there is more weight on the mains.

I agree with your skepticism about the "right answer". I haven't had to mess with mine because I love the way it handles and the tires show excellent wear at 40k all around.

[Twomed]

Less pressure will lower front axle loading....BUT, it will shift that weight to the drive axle. It doesn't disappear, you just move it around.


A lighter front axle may sound good, but on snow/ice/water and just all around I like my current distribution.


Again...as Monaco suggested in the old days...keep it within specs and comfort. I am sure there are several others running differently, not preachin' here, just trying to answer the OP's question.

[96 Wideglide]

Originally Posted by K7JV

I would love to hear a "right" answer. We have our tag on our '06 Countess III at 52 psi. That makes the loading on all six rear tires relatively equal, per tire. We carry 80 psi on those six tires, and had excellent wear for over 50,000 miles. We just did replace the tires due to age (9 years), when we replaced the front (Goodyear, due to the rivering that you may read a lot about) tires. Wear was not an issue on the rear tires, at all. There was some rounding on the tag tires due to scuffing in turns, but even that wear was not excessive.

Be careful, though. When you load the tag, you also load the front axle, and it is easy to load it beyond its rating.

We went thru a truck weigh scale in Idaho several times, and adjusted the tag after each weighing to settle on the 52 psi setting. With the coach full of fresh water, both holding tanks empty, the fuel tank full and the storage loaded for normal use, we ended up with 14,320 on the steer axle, 14,840 on the drive axle and 7,660 on the tag. We carry 115 psi on the steer tires and 80 psi (tire recommended minimum) on both rear axles.

If anyone has a definitive "right" answer, I'm all ears!

I will share that last winter, we got "stuck" in snow at Lages Junction in northern Nevada, in 6" of snow on top of a layer of ice. It never occurred to me to lift the tag to try to get back on the highway. I wound up disconnecting, finding a better spot with the car, retrieving the coach, reconnecting and taking a run at it to get back on the highway. Next time I'll try lifting the tag. Live and learn.

I would'nt want to be 300lbs from max on the front axle, when your drive axle is over 2.5 tons shy of max.
I realize that having all six of the rear tires carrying equal weight would be ideal, but I dont think it's acheaveable on these chassis.

[Randyman1]

I think mine is in the 42 to 45 range, we have similar coaches. That's what it was when I purchased it and I haven't changed it and the coach rides and drives great. Randy

[D Lindy]

I'd think you'd want all axles at about the same % of load capacity.

[moisheh]

If the FA is within even 500 lbs. of max you could be overloaded if the unit has uneven side to side weight.