Difference between 1/2" OD line and 1/2" ID hose?

When I built my horn, I decided to use 1/2" ID Goodyear hose to connect my solenoid to my horn. My horn is so close to my tank, so I mounted the solenoid on the tank and used a 3’ piece of Goodyear hose to connect it. What are the benefits of using air line instead of air hose?

Also, I have another question. What is my limiting factor or “weakest link”? My tank has 1/2" ports. I have a 1/2"male-to-3/8"female adaper in that port, connected to a 3/8"male-to-3/8"male 45 degree elbow connected to a 3/8" solenoid then my 1/2" ID hose connecting it to the horn.

One end of the hose (the end connected to the solenoid) has a 3/8" male barbed hose connector, and the other end of the hose (the end connected to the horn) has a 1/2" male barbed hose connector. The barbed part of both of these connectors (the 1/2" and the 3/8") are the same size, so my assumption is that these barbed hose connectors are the limiting factor of my air system but that the size of fitting (1/2" or 3/8") makes no difference at all. Is this correct?

bottom line is you need volume your pressure comes from the tank… and if you have 1/2 ports down to 3/8 then your pussing 3/8 into the horns even if u go to 1/2 at the horns… it seems like your running 3/8 that short… buy the dot approved line from hornblasters and go with 1/2… you will be more happy…

best thing is… go with 1/2 if u start at 1/2 and go to 3/8 at any time your slowing air flow down and wont really speeed it up if you go back to 1.2

You missed my point, but that’s ok. Try to picture this…you have a piece of Goodyear 1/2" inside diameter hose. That hose has a 1/2" npt fitting at one end and a 3/8" npt fitting at the other end. On each of those fittings is a barbed hose fitting that fits inside the 1/2" inside diameter hose. The inside diameter of both the 1/2" npt-to-1/2" barbed fitting and the 3/8" npt-to-1/2" barbed fitting are EXACTLY THE SAME. Both are limited by the inside diameter of the 1/2" barbed hose fitting.

Is the inside diameter of a 1/2" barbed hose fitting (which fits into an air hose with an INSIDE DIAMETER of 1/2") really that much smaller than the inside diameter of a compression fitting that fits an air line whose outside diameter is 1/2"?

It is…because simply think about it, if the 1/2OD line fits IN there, the line is 3/8" ID. 1/2" npt can hold a 5/8" barb, and a 3/8" can hold a 1/2" barb. 1/2" ID line, is 1/2" like…the npt sizes don’t have anything really to do with it…
I think that’s what your asking? If its a 1/2" compression fitting then the line is going to be smaller inside it, unlike the barbs, which a 1/2" barb is 1/2 ID

The weak point would be your 3/8" selenoid…1/2 at least, if not a 5/8" one to flow more air:)

I understand that, but the 3/8" npt fittings on the solenoid are much larger than the 1/2" barbed hose connections. Just looking at everything, the smallest point in the system seems to be the 1/2" barbed hose fittings. I am just wondering if the fittings that connect to the 1/2" OD air line are as small as the 1/2" barbed hose fittings. I could always up the hose size to 3/4" if I need to as well.

The 1/2" barbs are made for 1/2" inside diameter line, 1/2 compression fittings are for 1/2"outside diameter line…trust me, I tried fitting 1/2" OD line over a 1/2" barb and it did NOT work. The line is much smaller, about 3/8" ID. Your 3/8" selenoid is the bottleneck…the in and out might be larger then the barbs, but not the selenoid chamber itself.

Ok, thanks. Is there any way to measure airflow after the solenoid?

As far as I know, only with a flow meter.