>>? Any input with specific models would be a help !
One of the chores I had before leaving Austin after purchase of my '96 Winny Adventurer was putting valve extenders on. I'm one that has had good luck with them. I have had "bad" luck with pop on hub caps that tear extenders. Anyway, not a single tire dealer in North Austin would touch an extender. I hit some of the largest truck dealers in the area to no avail. Even the big RV dealership in Georgetown acted as tho they had never heard of an extender. One dealer said it was because of recent TX legislation that made a dealer liable if an extender failed.
So, I called my friend Ron Ruward who I knew disliked extenders to ask how he aired his rear tires. Seems he can get his hand between the dully's if I recall. But we also chatted about air compressors and what might work for me. He said that Sears, Walmart, and Harbor Freight might be a good place to start.
After checking out Sears and Walmart, I finally thought that Harbor freight seemed to have the best prices and I wound up buying a 2 gallon 115psi model for $79.99. Unfortunately, this unit would not do the job so I returned it and got a 5 gallon twin tank unit -- that was on sale for $89.99 -- plus I got a 10% discount as it was the only one left. So I got it for only about a buck more.
I will never know if the 5 gallon unit would do the job because when I got it home and it wouldn't work. BTW, the smaller units do not require adding oil whereas the larger units do. For whatever reason, this one was then returned. The sales person I purchased from was not there that day but they said I could exchange it or get a refund. They had no replacements and no other stores in the area had the same model -- and it was too late for me to have another shipped prior to my leaving.
The person helping me called the manager and he said, give him one of the 8 gallon units as an even trade if he is agreeable. As I quickly glanced at the price tag of $179.99 on that unit I said, "Why, yes -- that would work fine". So I now have the HF (40400 item#) compressor -- and it does a great job of airing my rig tires. It gives me 6.0 scfm @40psi, 5.0 @ 90psi, and 4.2 @ 115psi. Was concerned about space in a compartment, but it just fits and that was nice.
I also got a tire chuck with gage ($4.99 on sale at HF) that I was able to bend a bit so that it fits nicely through the front tire (after removing the hub cap) to the rear extender, plus 50 feet of hose. Have now driven from Austin to Gila Bend, AZ and have checked the tires each AM and they are doing well. I won't do it that often in the future, but now know that I "can" check all tires rather quickly -- and can add air if needed w/o looking for a service station to do the job. Am also looking forward to adding some air tools such as impact wrench, grinder, and blow handle.
I DO believe the 5 gallon unit at HF would have done the job and would fit into a compartment easier, but having paid only $81.00 plus for the 8 gallon, I couldn't pass that up. DO watch for sales at HF as they come up often and you can save a bundle. You will need at least a 5 gallon unit. BTW, Lowe's has some very nice units, but they were much higher than the other stores I visited.