Theoretically, the motor would be most useful on the climbs of the mountain stages. On the flats a couple of hundred grams don't matter, especially when most of the leaders are hanging back in the group anyway.
That said, bikes can already be made under UCI weight minimums of 6.8kg. Yet from what I've seen, most tour bikes are in the 7-7.5kg range.
That said, bikes can already be made under UCI weight minimums of 6.8kg. Yet from what I've seen, most tour bikes are in the 7-7.5kg range.