Originally Posted by
soyabean
Absolutely not.
This is downright dangerious, damages the integrity of the (aluminum) frame, and will 100% void the manufacturer's warranty.
You can easily cut a seat post, but never a tube stay,
Shop for another bike. Pay more if you must. There are loads of step-thru bikes out there with very low frames.
Perhaps a photo of the actual bike being modified.
I think the OP was wanting to cut down some kind of a mast which may well not be structural, although, as @
guy153 pointed out, the tubing thickness may not be uniform, and the design may be for a few inches of 27.2 inside diameter tubing, and larger inside diameter tubing the rest of the length. I.E. Support for the seatpost may not be uniform, and one may cut off a critical section.
But, one also needs to carefully consider the whole goal for the E-Bike as people above have mentioned. On a motorcycle, one can just put the foot down. But, on a "road" bike, one generally hops off of the seat when one stops.