GuyD wrote:It is fantastic around town and on smoother tar. But it is still too throbby for my liking on rough tar so it is definitely the tyres (as supplied in 2017 by BMW as it is virtually new).
Your 20" tires have 1" less sidewall height compared with the i3's 19" tires which could explain the tire noise. There's less sidewall to absorb pavement irregularities. Many i3 owners familiar with both the 19" and 20" tires have stated that the 19" tires provide a more comfortable ride.
GuyD wrote:I think I should look into alternative low noise tyres at some point. Anybody got a good recommendation? - although they may not be available in Africa...
There's only one 20" tire option regardless of where you live, so until a tire manufacturer decides to produce a competing 20" tire, no choices exist.
GuyD wrote:According to the read-out I am getting 5.8km per kW but that would indicate 34 kW battery use - huh?! I thought only 27kW was useable?
Brave new world for most of us: kW is a power unit, kWh is an energy unit. So your efficiency was 5.8 km per kWh.
The actual and usable capacities depend on temperature, how rapidly charge and discharge occur (i.e., charge and discharge current levels), and how well-balanced the 96 battery cells are in terms of capacity, charge level, and internal resistance. BMW states the nominal actual capacity as 33.2 kWh with 27.2 kWh usable. Some feel that the usable capacity is greater than 27.2 kWh under many conditions. You might have a battery pack with exceptional battery cells.