I've never heard anything about the fork mounts not being good for Carbon. My husband and I both have carbon bikes and considered those before we decided that if we were going to do all the work to put our bikes on top of our car, we didn't also want to have to take the front wheel off. So, we got a regular, two-wheeled, roof mount. What is NOT good for carbon bikes is having the arm that grabs the frame of your bike, instead you are supposed to get the ones that go over your front wheel against your brake. Otherwise you could damage the frame by putting too much stress on it.

-Jessica