My rear disc brake is always locking up when ever it gets hot. The axle is on straight and it spins fine on a stand and while riding it for a few minutes and then it will just lock up. What can I do. I just got this bike a few days ago and I am having alot of problems like having the triple clamps not drilled out enough so the handle bars dont fit and the graphics just peeling off. Customer service is great since they are mailing me brand new sets of graphics and triple clamps but I just want to ride it instead of fixing it. What can I do to fix the rear disc brake?