Recently I have had a lot of trouble with my tires on Onyx… The presta valves are different, but once you learn about them it is simple. I was looking for presta valve stem covers and found the link about presta valve adapters, here is a nice video.
Steve Sussman send a picture of this.
These are great when you have a pump that only uses the Schrader valve stems. At a dollar a piece that is a great buy.