The rubber straps used to attach the SPEEDROCKER mudguard to the rear wheel are not suitable for the front wheel. For the safety system to work properly, a rigid connection is required at the front. This can only be ensured by the hook-and-loop strap.
When you tighten the hook-and-loop strap firmly, its non-slip coating makes it hold just as reliably as the rubber strap.
You can find out more about installation in the tutorial: