Thanks for the info :-)

I was looking at the new Marathon Supreme thats rated at 42mm but early reports say they come up small at about 39mm so it would be fractional bigger but I thought its so small thats its not worth bring up. I would have the option to tire up to 50mm too so thats an option too.

Reason for 650B is I like the wheels size and the midsize wheels see to put to bed the age old 26" vs 700 debate (to some extent) but I like the slightly smaller wheels size with slightly fatter tires with out going all the way down to 26". Also smaller wheels are stronger too :-)