make sure the brackets for your luggage rack have been properly welded - We had a Swiss Visitor with a broken bracket recently and as a result I have had mine re-welded -one was cracked and ready to come apart!!! Cheers!
@ CLPlusFour, thank you. Suitcases are from Peli, ref iM2600 Storm Case.(https://www.peli.com/fr/fr/product/cases/storm/im2600/) . Waterprof, two can be fixed behind the car, and can be taken directly on easy jet company plane.