Originally Posted by
CrimsonEclipse
I actually have a folder with a telescoping seat post. (although I am not tall)
Folders are inherently more flexy, and longer seatpost and handlebar stems will also increase the flexy.
Generally not a problem unless you mashing out of the seat, but keep it in mind.
Try it out with the stock equipment and you might find out that extensions aren't necessary.
To gauge the seat height you might need, your inseam will be a useful measurement.
Note: weight is a common limitation on folders so check ahead of purchase.
Your ideas are fine and have been successfully completed on multiple folders before.
Best of luck!
edit:
and bike pics if you purchase!
(OP) All good points above; Crimson is a longtime folder contributor.
I would also add:
- Telescoping handlepost/riser (the long verticle part between the head tube and handlbars, not a horizontal "stem"), are less rigid in general than fixed height handleposts, due to slight movement at the telescoping joint, but acceptable for many. My handlepost is fixed and tapered steel and very rigid, even when climbing out of the saddle, with heavy shopping loads. Its height is equal to a telescoping post at max height, and I like high, so perfect for me. Brompton ($$$$) uses all fixed posts, but available in short, medium, and high lengths, plus flat bars or deep bent bars that can swing fore and aft for more fitting.
My seatpost is the largest diameter I have seen, 33.9mm, so very rigid, even in aluminum. Bike Friday uses skinny telescoping steel tubes for both seatpost and handlepost (in order to use standard parts like typical stems and seatposts), which are inherently more flexy (fore/aft and lateral), but may offer a small bit of suspension on both due to the flex.