Confused about Air line

Hey guys i just got a set of nathan k5la horns from hornblasters and i’m confused about the air line to run! Everybody says 1/2" or 5/8"s well does that mean inner or outer diameter? because if you’re running 1/2" OD then it truly isnt getting 1/2" worth of air seeing how the actual inner diameter isnt 1/2" right? I went to lowes to check out what they had and there was so many different types to choose from also there’s like a rubbery clear kind that was more expensive and a more thicker one with a plastic feel to it?

thanks for the help in advance guys

that’s what i had in my hand at lowes but i kept double guessing myself because doesn’t that mean everyone whos running that (1/2" OD) isn’t really giving there horns a true 1/2" of air. So should i go with the 5/8" OD and be safe for sure?

well hopefully someone with a k5 will chime in, (no pun intended, lol) but my way of thinking is the port on the manifold is 1/2" ( i believe) so if you got 5/8 of 1" etc its just gonna create a bottle neck… From what i read on the forum there are a decent amount of ppl that run 1/2" for the k5

dont use 1/2 OD…use the 5/8OD…its the real deal same as train…the size of line makes allll the difference…it cost me 2 dollars a foot at the local big rig shop…its worth it!!!dont get 1/2OD especially not hornblasters its super expensive

use this one…other was wrong link
once u get there use this product number

how is hornblasters expensive at $1.00 a foot?

thanks guys i think i’m gonna go back to lowes and get the 5/8 OD with 1/2" ID stuff! and figure out all the fittings also. Ya the hornblasters stuff was really cheap compared to the stuff at Lowes which is like $30 for 25 feet i should’ve just ordered it when i ordered my horns but i thought i could use my old stuff i already had but it was only 3/8" and i don’t want to wait another week for it to get here!

get the quick connection fittings…all u do to connect is push in…then pull a little big… it will be very easy to install and u wont mess with those crappy compression fittings.

k sweet do they make the push in fittings for 5/8" OD? will they have them at LOwes?

they make them…but maybe not Lowe’s…try 18wheeler shops…they use those for air brake lines…that how i get them

i get semi brake hose from a local shop called mako hose and rubber

Thanks, good post nick… So 5/8 is the OD and 1/2 is the ID. Good info. I’ll be getting the 5/8 OD line too.

sweeeeet! ya no problem what kind of horn are you runnin?

The horn pictured in my avatar… It’s got some quirks right now tho… dunno wtf. Its a air guzzling Leslie RS-5t but its not under my truck yet… Still gathering all necessities.

right on Leslie’s are the bomb. what Psi are you running it at

When installed under truck im gonna run it at 145 max because more than that will damage it. But that big ugly tank under it in my pic is a temporary rig I used to blow it at a Georgia Southern football game while tailgating in the parking lot. (lot of trouble that day lol). I blew it at 100 psi that day. But that tank has alot of rust chips in the bottom of it and I think some got into my horn somewhere. Dunno whats up with it for now.