Here in one of our local trails, a guy riding his even lighter than 20lbs time trial bike ran into a lady jogging who thought it would be wise to just do a U-turn without checking behind her, guess what happened when that lighter than 20lbs bike and rider crashed into her? Yeah she died from injuries sustained from that crash, and our trails are limited to a 20mph limit. So you ask what kind of danger can you be on a 20lb bike? How about ending someone's life, is that good enough for you to run a brake? Hell if you can't afford it send me a PM I'll ship one dammit!