Tire width. For fire roads you’ll want 28mm minimum and gravel bikes will go as wide as 50mm. Good for comfort and performance. Geometry- don’t get a race bike, use the stem at a positive angle. Get a saddle you like. Serfas and Selle Royal offer 3-4 month trial period or your money back.

Solid lights at night, especially headlights. Strobe functions distract the eye for everyone you share the road with, and they’re banned in Europe for precisely this reason. A steady light is much easier for the eye to track w/r/t distance and speed.