With a Dinnotte 200L on my bars and a Fenix L2D on my helmet, I went over 40mph on a few downhill stretches last night. Felt fine. The long throw of the L2D really helps at speed. However, this was on a loop road in a state park, where I pass about 2 cars on average per 9 mile lap, plus I've ridden it dozens of times and know every turn.