BMW i4
Why Integrate?
Roof racks are popular for a reason.
It saves time in a busy life
It may also save life; no more worrying if you forgot to secure the rack.
Why rear?
Lifting bikes, especially Mountain or Electric ones onto a roof is hard; There are no bike carriers rated above 20Kg.
With electric cars, aerodynamics is paramount.
Somewhere around half the energy of your battery is used moving air.
Roof carrying kills range for EVs, Chat GPT says 20-35%.
Put your stuff out back and the impact is 8-18%.
No Towball
The towball joint limits the load.
German DIN standard restricts towball racks to 81Kg inclusive, which normally means 3 bikes.
Towballs can catch your shin, which hurts
Removing towball, can damage your knuckles, also painful
Parking in tight spaces is more difficult.
If you do have a little knock the damage is often more substantial
Finally they can look a bit clunky, and possibly are illegal if the numberplate is obscured.
Launching on BMW i4 Sports