Ok so iv been searching and I have a feeling this has been covered time and time again. Nevertheless pardon my poor search skills.
I scored some 300zx brakes off Kijiji for a very good price. Only problem is I don't know what size I have 26mm or 30mm. I know just a couple days ago I see something I can measure and make sure what I have.

Didn't save it and don't remember what the measurements were.
Any help?
Thanks folks sorry if my old repeated post is an annoyance.

Quick way to check, use a magnet. if it sticks they're 30mm irons, if not it's gonna be aluminum which can be 26 or 30.

Google search turned these up as the first 2 hits;

https://www.carthrottle.com/post/alzy4kz/
https://importnut.net/the-definitive-30 ... e-upgrade/

The difference is in the thickness of the rotor. Second link has pics measuring with a simple tape measure so you can tell which you have.

Car guys should have a set of inside and outside calipers.

Measure the opening in the caliper - easy peasy. In a pinch, you can use a ruler.

AND welcome aboard!