WTB Nanos are good tires, and the 700x40 size is great for a lot of hybrids. I'll bet they just barely fit in an FX frame! I ride a similar tire (Vittoria Mezcal) in a 27.5x2.1 size and run about 25 psi front and 35 psi rear. Gravel and dirt riding is sublime at these pressures -- welcome to the wide tire club!