The bicycle chain is (in my opinion - and I go much wheel) the weakest point of every bicycle! Although it is (at top components in super good condition), an efficiency of about 98% to awarded her, but which wheel offers! Top components are as shifting the Rohloff (costs without wheel already> 800) or good, clean derailleurs - and this it is little! So hardly comes a wheel to the "promised" efficiency.
This bike here offers the best solution !! - Namely shaft drive (Kardan). This is fully enclosed, can not get dirty, therefore, requires no maintenance and retains its theoretical efficiency always! As a circuit is a good 7 - speed hub.
To notice is that the wheel is very light (!) - And not as "enemies" of this technique attach hard.
