A question about seat post sizes

holman210
holman210 Posts: 108
edited February 2009 in MTB general
Hi just a quick one!

Im trying to buy a thomson seat post for my bike, but im a little confused with the amount of sizes. I asked Halfruads about the seat post size and was told its 31.6mm. I found a post on ebay thats 31.8mm, is the 0.2mm really going to make any difference??

Why is there so many different sizes, 31.8, 31.6, 27.2, 30.9, 26.8 and more!

Thanks!
Felt Virtue 4 - Fox RP23 PD - FSA Carbon Pro handle bars - SLX Brakes 180/160mm rotors - DT Swiss XMC130 - SLX rear mech and shifters - Titanium bolts - Mavic Crossrides 09 - Thomson stem - Hope SS Bottom bracket - SLX crankset

Comments

  • nicklouse
    nicklouse Posts: 50,675
    yes it will "if" you need a 31,6 then you buy a 31,6 not a 31,8

    But you could buy a 27,2 and use a shim to take it out to 31,6mm
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • are the shims a reliable way of doing it or am i just better off waiting till I find a 31.6 its not urgent and cant afford a new one, so theres some "as new" ones on ebay going for about half the price.

    Cheers!
    Felt Virtue 4 - Fox RP23 PD - FSA Carbon Pro handle bars - SLX Brakes 180/160mm rotors - DT Swiss XMC130 - SLX rear mech and shifters - Titanium bolts - Mavic Crossrides 09 - Thomson stem - Hope SS Bottom bracket - SLX crankset
  • Shims do work, but if you can buy the right size post, get it. Yes there are many many different sizes and you do need the right one. I have a Thompson post on one of my road bikes and it is brilliant.

    Easton make 31.6 posts and are very well made. A lot of them are available in 400mm lengths as well :wink:
  • Does make a diffo, as said. I have a Marin with a 27.0 pillar and can't really get a 27.2, the most popular size, in there without muscling it! :(
    AT MY AGE, I SHOULD KNOW BETTER !!!
  • shame there isnt just a large and small lol suppose with so many different frame makers its a bit hard to have a IS standard
    Felt Virtue 4 - Fox RP23 PD - FSA Carbon Pro handle bars - SLX Brakes 180/160mm rotors - DT Swiss XMC130 - SLX rear mech and shifters - Titanium bolts - Mavic Crossrides 09 - Thomson stem - Hope SS Bottom bracket - SLX crankset
  • Just ordered my Thomson stem! :-) should look good with the post
    Felt Virtue 4 - Fox RP23 PD - FSA Carbon Pro handle bars - SLX Brakes 180/160mm rotors - DT Swiss XMC130 - SLX rear mech and shifters - Titanium bolts - Mavic Crossrides 09 - Thomson stem - Hope SS Bottom bracket - SLX crankset