The invention refers to endovascular catheters and methods useful to endovascular surgery. In particular, it refers to support catheters with balloons that are used for the placement or the forwarding of the guidewire through demanding tortuosity and important vascular stenoses in cases where the guidewire needs the best possible backup support of the catheter. This is achieved with the development of an endovascular support catheter with a mobile balloon, which has the ability to move along the body of the catheter, at its distal part. The movement of the balloon is achieved with the use of two mobile external rings, one inner wire circuit, and one control handle which is found at the proximal end of the device. The mobile balloon allows the catheter to move inside the vessel even when it is inflated and basically anchored within the vessel.