I ordered a couple of caps for use with my gravel, road and mtn bike however, the flat caps don't work for a carbon steerer tube with an expansion type nut. These caps are only compatible with star type nuts because they are to tall. So the caps for my gravel and road bike cannot be installed. Also the flat caps don't have a lip around them on the bottom inside to keep them nice and aligned in the steerer tube. Every other steerer tube cap I own has this lip. I ended up putting the caps on my other mtn and older steel bike but those bikes are not used very often and were not the intended reason for the purchase. It would be nice if KUSTOMCAPS would provide this information regarding compatibility with their caps.