I guess from everyone's comments I have been prudent to do only night group riding on roads that I ride all the time and everyone has a substantial light. There are also few hills of any size in this part of central Indiana. I have only done one solo ride and another ride with just my neighbor. I had my Princeton Tec Switchback 3 helmet and L&M Vega on the bars and he had a Minenewt.X2 Dual. So I felt like we had sufficient light even on a route that I was riding for the second time and first time at night. I have never used as powerful a light as some of you and may feel differently if I saw what I was missing or if I had hit something that caused a flat or wrecked a wheel or injury. So far so good in a full season of night riding.