I am buying this for my Specialized Aliez...
I am buying this for my Specialized Aliez road bike. I have measured the current seatpost at 1 inch OD. What size should I order?
Not being sure how you measured to OD on your current seatpost I can't say forsure but a 1 inch diameter with be a 25.4mm post. This is sorta a rare size and not likely what you have on your Specialized. From what I can find most to all Specialized Allez frames used the 27.2mm size since 1993. Unless you used a dial caliper to measure the 1 inch OD buy the 27.2mm seatpost.