What is it? The modern setup for Mainstreet Pedicabs is using a 27.2 mm seatpost with a shim that spans 31.4 mm to 27.2 mm and a 34.9 mm seatpost clamp. Even though the seatpost tube on a Mainstreet is 31.4 mm, the combination of a 27.2 mm seatpost and a shim are used to prevent the seatpost from seizing to the seatpost tube. For cyclists, this seatpost will fit a 31.4 mm seatpost tube. This seatpost is 350 mm long.
Why we love it? Using this combination of seatpost and shim prevents the nightmarish scenario of having the seatpost seize to the seat tube. This has happened within our fleet, because we purchased an older pedicab that used just a 31.4 mm seatpost. The result was having to re-weld the tube.
Pro Tip! If you are having trouble firmly securing the seatpost with the stock Mainstreet setup, it could be that the seatpost tube has stretched out. This could be due to improper seatpost installation, and is common on Pedicabs that are over a decade old. If this is the case, don't use the old soda can hack. Size up the shim to this.
What are the options? This seatpost comes in silver.