Seat Tube Collar Section

A close look at the inside of the seat tube collar that is pressed into the seat tube with an interference fit ( approximately .005") before the fusion weld. Notice the 7 degree taper , ( approximately .375" long), to reduce any straight line stress concentration on the seat tube. This makes the seat tube go from .035" wall thickness to approximately .078" wall thickness in the seat tube pinch area that is 3.250" long. This is all done to make the seat tube pinch area as strong as it needs to be to clamp the seat post properly, while keeping the rest of the seat tube as light as possible, basically putting the metal where it needs to be.