K Shred Ketoboth the rear and the sides. Check for brightness before you buy one. Install the light where it makes the most sense. We held off on buying a speedometer and odometer unit for our bikes, but once we got serious about losing weight and getting in shape, this feature became a "must have." You simply cannot track your progress without knowing how far and how fast you're riding. If you already have a bicycle, take it to the bike shop for a safety inspection each season. They should check the gears, tires and brakes