Nothing is screwed, but mounted on larger base carrier with three brackets and clamping lever. And since the statement is kept small, it takes a little, but if you have then understood the system, it works, sure to tighten the carrier onto the roof rack. At the rear bracket of the carrier is lockable, and secure it against theft on the base support.
The wheel is secure as well as oval aluminum frame with two large jaws are kept safe. Here is a quick clamping device available that can be completed. This can on right or left side operation by unscrewing the clamping device and pull out the screw be easily repositioned.
The lock on the jaws for the wheel frame I removed a lot of effort, since it is well locked, but then closes again very bad, so I subtract a star.
The wheels are fixed with sturdy rubber straps, which is very simple, and which are also very quickly released again, perfect to use.
Not so perfect because it is very thin, seem to me the plastic parts where the straps are attached. In this the wheel is put, and I'm curious how long the straps keep this thin plastic. Nevertheless, I'm going to buy a second carrier, because so easily I've never prepared bikes on the car roof safe and stable for transport before.
