A medical device delivery system can include a dilator including a tip having a taper in a distal direction, a coupler, and a flap that radially protrudes from the tip. The flap can be configured to bend against a body lumen to cover at least a portion of the delivery system when the dilator is tracked through the body lumen. A medical device delivery system can include a dilator including a tip having a lumen and a coupler having a lumen. The coupler can be configured to securely connect to the tip such that the lumen of the tip is aligned with the lumen of the coupler to allow a guide wire to pass therethrough. Methods for loading a medical device into a delivery catheter are also disclosed.