The seat post size is 27.2 x 350 mm. I also have a 2016 Townie 7d converted to electric except I used a rear hub.
After a few years of lurking around here and endless-sphere, I finally took the plunge and converted my Electra Townie to an e-bike. I’m now over 530 634 1386 2000 2530 miles in and couldn’t be happier. I had ridden this Townie and prior Trek Pure thousands of miles and along the way tuned...
electricbikereview.com
I bought a Suntour NCX for my Townie but would not recommend. The seatpost itself is nice but you are unable to level the seat in the post mount without it hitting the seat post rails.
Later, I replaced the NCX with a Satori Animaris post which is also quite nice and doesn't rub the rails. These posts used to be a bargin. I paid $55 on Amazon. You can still find one on eBay, but the ask has more than doubled.
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