Bikers and their teams are known for removing as much weight as possible from their bikes. Would love to see the math for weight/power/time ratio for a motor like this. Would it be worth it considering you'd have to expend additional watts lugging it around all stage? My guess is probably not. Especially on a mountain stage which is where the tour is really won or lost.
There is a minimum weight requirement for bikes. I remember reading somewhere that they actually add ballast to some of them because they can be made so light.
Not any more - nowadays being aero is more important and that adds quite a bit of weight. And disc brake sets are also heavier than brake pads used to be.
The UCI weight limit still seems to be in place. Disc brakes have been allowed since 2018 it seems.
It is, but the minimum weight is harder to achieve with the extra weight of the disc brakes...
The Specialized Aethos shows it's not hard to achieve at all. These are regularly built up to less than UCI minimums.
Agreed.
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.
The difference between the top 0.0000001% of humanity and second place is very, very small. Fractions of a watt. Adding just 10W would be game changing, and modern lipos and brushless motors add far, far more power than their weight penalty subtracts.
10W for a sustained time perhaps but these are looong climbs. Col de la Loze is 26.4km with an average gradient of 6.5%.
A 60Wh battery weighs about 300g. That stage is about 5 hours. 300g seems a pretty small price to pay for a 10W boost, especially if you achieve it by making the bike be under the limit and then adding motor+battery (switchable with a dummy weight, of course) to bring it to spec.
(The motor, of course, would probably weigh more - but it remains the case that you can build a bike that weighs under the minimum.)