Posting for future reference for X owners who may find this helpful.
I’ve been wanting to put larger tires on my X for a while now, but was never sure if I should push the listed max size of 700x40c. I had heard scattered claims that 45c would work, and after running 650bx47c for a while with no issue I thought I’d try out these Schwalbe 700x45c Allround tires. They seem fit perfectly fine, and I don’t see any potential issues that would cause it to be a problem aside from serious soupy mud. 2x users may not be able to get away with 45s in the rear however. The fork could probably fit 50c or larger.
Hoping this helps someone else using the Poseidon X, as I felt like I had trouble finding info about it. Cheers!
by morbidrhythms