Is exhaust tube measured inside or outside?

[Mark (smokey mow)]

Dumb newbie question to which I should really know the answer.

I need to order a short length of exhaust tube, but are the measurements taken for the bore diameter or the outside diameter?

My exhaust has a bore of 1.75" and an outside diameter of 2" so which size do I need to be ordering? I don't really want to get the wrong one.

[AidanPlace]

Tell them you want 2" outside diameter 1/8" wall thickness.

I think  

[Blatman]

Yup, give them both.

IME measurements are usually bore diameter for the tube, but outer diameter for the body of the silencer. It's confusing...

[Mark (smokey mow)]

Thanks chaps, I found the answer in the end after a brief search.

From the Jetex website

QUOTE

Jetex parts are designed to fit together using slip joints. For example, one end of a 30 degree 2” bend will have a 2” inside diameter, while the other end will have an outside diameter of 2”.

So it looks like they measure the outside diameter for the parallel tube end and the inside diameter for the swaged end.

[s2rrr]

That's a pretty thick exhaust wall thickness approx 3mm. I would check the 1.75" and 2" sizes. Must be pretty heavy as well compared to mine which is closer to a millimetre wall thickness in stainless system.

Bob