Originally Posted by
mrblue
Why do some frame manufacturers make their frames for 27.2 seatposts, while others seem to favor 31.6? What are the advantages and disadvantages of each?
Thanks.
Traditionally 27.2 would be for road bikes which have skinnier tubing, 31.8 for mountain bikes which had fatter (stronger, stiffer) tubing. Of course these days that's blurred but I think it's still more common to find the skinny seat posts on road bikes (both my road bikes take 27.2).