We have an air hose with a "duster" handle on our coach. A search of the forum showed several posts about supplemental supplies for use when the coach is not running, but not much otherwise. Will this hose, with an inflator attachment, be adequate for topping-off tire pressure?
Matt B
1994 U-240
My experience with a 1997 U295 has been that I can easily air up the tires to about 95 psi with a hose connected to the air supply in the fuel/propane bay. I can get to 110 psi if I fill immediately after I hear the "whoosh" sound that occurs when the air system reaches maximum pressure. On our coach, the engine must be running in order to have enough pressure to properly inflate the tires.
I just fixed a fitting on my small electric air compressor and plan to carry it in the coach in order to generate compressed air when the primary engine is not running. The small electric compressor generates in excess of 120 psi of pressure at a volume sufficient to top off big tires. Other folk carry compressed air or CO2 in a portable tank.
Thanks JD. My inflator handle is headed for the bay!
Matt B
In a word, YES, this on-board hose will be fine to inflate the tires with the engine running.
Suspect your front tire pressure should be around 95 and rear around 85. This to be confirmed by actually weighing the coach as loaded and then referring to your tire manufacturer's inflation tables.
Brett
1994 U-240
On my coach I removed the air chuck from the hose and replaced it with a female air line connector, so that I can use air tools and also air up the coach without starting the engine by connecting to an external compressor. Requires the proper adapters of course, and the air chuck has one so that I can still use it. When using air tools, the coach air tank and engine compressor are rather small volume wise, so I idle the engine at 1000 rpm and wait for the pressure to build back up after a short period of use.
I use mine but still look for a small unit to carry in the bay.
One thing the onboard compressor has that an external compressor probably does not have is an air dryer. Dry air or nitrogen is supposed to help the tires by causing less pressure change when the tires get hot and having no water in the tires cuts down on corrosion of the wheels.
See the article, www.getnitrogen.org/pdf/print_articles/Bridgestone_FirestoneCommercialTruckTires.pdf (http://www.getnitrogen.org/pdf/print_articles/Bridgestone_FirestoneCommercialTruckTires.pdf)
The trick to airing up tires from the coach air supply is to run the engine at fast idle. I use a chuck with a built-in air gauge (Tractor Supply) so I can watch the building pressure and achieve the setting I want for the front tires-110psi in my case.
I made nearly the identical chuck with gauge, made from Harbor Freight parts a couple of years ago. I used it again today, with the engine running at fast idle. Works great.
I learned a technique to running the engine at fast idle while at my recent service trip to MOT.
- Ensure transmission in Neutral and Emergency brake is ON
- Accelerate engine to desired RPM
- Cruise Control will hold engine RPMs at desired level
At least on the 1993 Caterpillar 3116 (and I expect will function the same on the 1994 model), to engage fast idle, merely turn cruise control on (yes, in neutral) and roll the switch to "set". Then roll to "accelerate" until the desired RPM is reached.
This worked with the OE Bendix CC and with the replacement electronic cruise from King Control I went to years ago (same steering column-mounted stalk).
Brett
Using the accelerate button seems to be a better controlled way Brett!
Ron,
I suspect our cruise control systems are VERY different, but will give it a try.
Thanks.
Brett