Anyone riding 650B & 700C?

Obviously not at the same time, that would be weird.

Just interested to hear some real-world experiences beyond the marketing hype.

Currently running tubed 40mm 700c knobblies for my offroad excursions (WTB Nanos)

Thinking of going tubeless, which means new rims, and wondering if I should go 650B at the same time.

For the tracks I ride the Nanos seem adequate in terms of comfort but they're not exactly fun on the tarmac sections. So I was thinking of something like a WTB Byway in 650B for the dry, hardpacked gravel I usually encounter. Faster rolling for tarmac, with enough tread to handle the gravel sections. I'm not about to go lobbing my tourer down singletrack so I don't need anything too extreme. I ride the Nanos at around 60psi (with tubes) and I guess I could get away with the Byways way lower than that if running tubeless?

Am I really going to notice a world of difference between 650B & 700C? And if so, is that going to be more down to running lower pressures because I've gone tubeless?

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.