WTB Bee Line TCS Light 27.5 Mountain Tire. The WTB Bee Line TCS Light 27.5 mountain bike tire blurs the lines between cross country haste and trail versatility. Its ramped knobs and even tread dispersal create consistent working edges that hang on for lateral traction yet spin up to speed effortlessly, making for a tire that is unquestionably quick. In addition to the stellar tread design, there's also WTB's TCS and Light technology on board. TCS stands for Tubeless Compatible System so you can get all the performance advantages of a tubeless set up. Additionally, WTB's Light casing reduces rotating mass and contributes to a supple ride. It's most definitely time to make a bee line to the trails.