Originally Posted by
operator
100% wrong and bad advice.
Seatpost sizes cannot be "approximated", you NEED the exact correct size. Shims are only temporary until you can get the proper size, a stopgap, not a solution. Seatposts come in .2mm increments all the way from 24 ~ 32mm.
+1
More like you *want* the correct size so stuff doesn't get more complicated in the future.