I am working on building my bike tool collection. There have been a few situations where I could have used a cone wrench. I looked up sets and most come with the following sizes, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm and 19mm, so I assume these much be pretty common. I notice the also sell them 20mm+ as well. I am not mechanically inclined enough to just look at the part to determine what size I need so I cant just purchase an individual wrench. Thanks in advance for any replies.