If you thought you had finally found a short, straight valve stem that fits into the recess on your BMW motorcycle, you were wrong. Where the description states that the seat is 1/2" in diameter, this is not the case. It's 1.6 cm and who says "1.3 cm"? The diameter of these rods is 16mm. The length measurement they show, 41mm, is pretty close - with the cap in place I measured 40.8mm and 38.3mm with the cap removed. Well, on the other hand, if the 16mm size is right for you, then this is a good