I got this 1986 Miyata 610, and it had a 26mm seatpost made by a Japanese company called Strong. When I install the seatpost, the bike clamps down all the way, and the seatpost still moves. I put this seatpost in a different Miyata with a 25.8 mm seatpost size, and it was just too big. That leaves me to believe that the seatpost that was in this bike is a 26mm, and the right size is around 26.2mm. But, I am not sure and I need the help of anyone who owns or knows about this bike. What was the original seatpost size?
Here is the bike.
Here is the bike.
