Fly Proton Cassette BMX Bike 2019The Proton has beenrefined for 2019 just like the rest of the Fly mid range bike line, The fork has been upgraded to a hydroformed 1 piece steerer tube. This bike now comes with a Trebol headset, a stronger 510 chain, bigger bars and a taller standover height, improving the overall look and feel, The cranks have been upgraded to the clean Trebol Bueno cranks. The 2019 Proton now comes equipped with four pegs, a shorter 13" rear end and shorter 28mm