Compass 650b 42mm vs 48mm Comparison
I fitted a 48mm Switchback Hill tyre to the front of my Soma. Rear is a 42mm Babyshoe tyre. Visual comparison below. Click to enlarge image.
For reference, they are mounted on Pacenti Brevet Rims, with innertubes at 40psi. Front tyre is brand new and will stretch out little (currently 45mm) and rear is used (measures 39mm).