Hi Forum, I've had an Audi garage fit an Audi detachable tow-bar (to my A3 Sportback 2.0 TDi (8P3)), and the part numbers on the fitting manuals they gave to me afterwards are: 8P4 092 155 Mounting instructions 8P0 055 204 H Electrical wiring guide ...but the manuals don't seem to indicate whether the detachable ball-head is made from steel or aluminum. I'm looking to get the Audi compact bike carrier, which is listed in the A3 accessories guide as: part num: 8R2071105 ...but it says it's for a steel tow-bar and not aluminum. So, my questions are: 1) Can anyone tell from the part numbers above whether the tow-bar ball-head that I have is steel or aluminum? 2) Does anyone have the Audi compact bike rack ? If so, is it any good ? Thanks peeps. Dave.