toby wrote:May I add yet another question?
Do I have to fit dynamo rear light + IQ Fly + Schmidt 28 dynohub; or can I just fit IQ Fly + Schmidt 28 dynohub, and use my existing battery LED rear light, or will this damage the light or hub?
It's probably risky not to, unless Busch & Muller specifically state that it's OK. The Peter White website in America reports overheating failures of the Inoled LED headlamps caused by owners failing to connect to rear lamps, so the same may apply to the IQ Fly. To be fair to the designers, dynamo headlamps are built to operate on 2.4 watts, not 3 watts. Not fitting a rear lamp means that constant high speed running (long descents) can damage the lamp. The old argument for omitting the rear lamp - trying to maximise headlamp output - has become almost irrelevant with the spectacular performance of these LED lights.