Hello! Would appreciate any advice on the following situation:
-My 12-year-old son needs a bike to commute about 1 mile to and from school.
-We live in Southern California, so there are lots of hills on the way route.
-Thinking about a used Trek Mountain bike from CL.
Any ideas about good models for this type of commute? Does he need 21 speeds or is 10 enough? I saw a nice new one Trek 3500 13" at the bike store, but it was $400 out the door. Would like to spend $150 to $200. Are the stock tires (kinda knobby) ok, or do I need to put on "street" tires.
Any idea if the hills will be bad for his knees? He's an athlete and his body already gets a lot of abuse!