Gotta echo what is said ^^ here.
I teach scuba as a side hobby. The stuff I teach isn't your basic "let's learn to dive" stuff, but more along the lines of "let's do our own stupid tricks in caves and with fancy equipment that is hell bent on killing you". I see a lot of people that are fantastic divers but absolutely crappy instructors.
When I cared about racing, I knew a lot of really fast guys that got into coaching. Some of them I think were probably pretty decent, but some were definitely not. Being fast on a bike doesn't necessarily mean you are good at helping others.