It's certainly not right for everyone, but it is a valid technique.
- Some people don't feel that they can drive safely without having instant acceleration available (I recommend those people drive automatics or use the lowest gear possible at all times).
- Some people drive in places where it is illegal.
- Some vehicles do not accept neutral coasting (my wife's Isuzu's transmission overheats with extended neutral coasting).
- As I said, having no experience on motorcycles I can't say if it's valid for motorcycles.
For me it feels safe and comfortable I can always count on the Newton physics Anyway, I don't literally shift to neutral: that's too far (would have to shift through all the gears down to N then back) and shifting out of N while rolling too fast makes the gearing grind which is scary enough... I just hold the clutch instead, so it's very quick to get into gear again (matchin the revs is recommended though ).
Coasting in FAS is a bit trickier and I don't do that as often as in 'neutral'. I know a few places where it's very beneficial, though FASing a MC too often is not good anyway, I think, because they have much smaller batteries than cars have.
On the validity of coasting or P&G on bikes:
- I think they're worse at it than cars because of the much less momentum (they're much lighter) vs their worse aerodynamics. But I have no experience with cars, so it's just a guess that they lose speed much quicker. Once I saw a bus (I sat on one of the first seats to see the instruments, I was studying pros' techniques ) coast through half of our village (from 70 down to 40km/h, and yes, that 70 was illegal) before using the engine, though, so I may be right I can coast to the next street there, at most
- But I also think that most of them need it badly because they cruise at legal speeds with so low load that they must be inefficient. i-DSi, if your CBF is tuned to higher speeds (OK, I'm not an expert here ) it may can take advantage of it
- I also think we need more reasonably tuned MCs. At least we who don't use them as toys. I would never take advantage of a setting that makes my bike the more efficient at 160km/h
I'm gonna try some P&G with my car !
But it will be hard to see any result, as my fuel consumption decreases anyhow now. No more freezing days, and already some 'spring-look-a-like days'. Went from a very steady 5,4~5,5 (last months) to 5,2 l/100 km in the dashreading the first 100 km of this tank fill (real consumption is higher and reflected in my gaslog). It will be the first spring and summer time for me in this Civic. But in summer I will use my MC again.