I used to go downhill on a crappy Magna mountain bike in my neighborhood, which is all hills. Was doing 35 mph on a crap 35 lb bike. A month later, after taking the bike to school, the brake cables snapped. I still wonder what I could have done if that happened a month earlier. As noobs, we like to do stupid things. The best idea is to keep the leash on and check the bike over and over to look for clues