Can I put a 31.6mm seat post where usually a 30.9mm post is?

anytear691
anytear691 Posts: 84
edited December 1969 in MTB workshop & tech
I must be thick, but I dont want to buy this 31.6 one ive seena nd it not fit. cheers for ur help
"Convoy?!, Micheal your spending you time with someone who uses a collective term for a single vehicle!"