Hi, I just joined, while searching for, "How to make a high powered head light." I have cycled to work, off and on for 35 years. My new ride is a short 35 minute sprint-twice a day, to/from work. I was 6' 3" & 205 in the 70s, so in June, I went back to riding to work, to add aerobics into my week. I would rather lift weights everyday, but then, its too easy to stay at 248 lbs (not good at 55 and a bad left knee). Since 6/1/09, I have dropped 20 pounds. I had two knee surgeries last year, so cycling has been the perfect PT. I want to drop another 30 pounds, to get 50 off these knees. The wife and I ride Hybrids, with 125psi Road tires on them. We may buy road bikes next. The other bonus to riding to work? We leave the cars at home!