600 miles on it. It is my first mountain bike. It has shimano components on it. The chain is out of spec so its not shifting. Most of the miles were on pavement. Maybe 80 miles were off road. But it still seems quick to me. I thought I kept the chain oiled well enough but maybe not? I also think my shifting technique was not good and since it was my first bike it was a learning experience so lots of shifting and riding around in the wrong gear but having said that I still think its early. Any advice on how to improve the life of these new components? TIA! Getting ready to go to NC next week for some real mountain biking!