I am looking to buy a used Trek Navigator 2.0 or 3.0. I currently ride a Trek 6700 and have two herniated dics that can't handle my bike anymore. I rode the Navigator 2.0 last weekend on a 35 mile ride and my back didn't bother me once. When I ride tht same trip on my bike now, I start to feel pain in my lower back about 10 minutes into the ride. My question is does anyone know where I can look to buy a decent used Navigator and even trade in my bike for one? Thanks everyone.