The racelight 4s disc frameset for 2015 the ultimate winter bike gets the ultimate upgrade with the addition of disc brake mounts internal cable routing and a brand new carbon fork to match disc brakes really come into their own on the grimy wet roads that this winter bike has to endure and coupled with up to a 32mm tyre and full mudguards it makes life a little easier for the rider too the inboard disc caliper mount is the new shimano flat mount standard and is very minimal this frame ha