what bl**dy size is my seatpost

geordiefella
geordiefella Posts: 302
edited November 2010 in Commuting chat
i got an old marin bear valley se. got some new winter tyres etc but for the life of me i can't find the seatpost.

googled the seatpost size 27mm great. ebay>seatpost>doesn't fit.

well, ebay again 26.8mm, arrived, still too big. tenner each and i'm getting a collection of unsellable posts.

where do i get an internal tube measurer?
anyone know the actual post size i need?
does anyone know where my original one is? It's here somewhere.

Happy New Year.

Geordiefella
Cannondale BadBoy Rohloff
Cannondale SuperSix / 11sp Chorus
Ridley Excalibur / 10sp Centaur
Steel Marin Bear Valley SE
Twitter @roadbikedave

Comments

  • cjcp
    cjcp Posts: 13,345
    Measure the internal width of the post, but you'd need a vernier caliper to do it accurately, I think.

    Can you get a shim from your LBS to fit the 26.8 post?
    FCN 2-4.

    "What happens when the hammer goes down, kids?"
    "It stays down, Daddy."
    "Exactly."
  • geordiefella
    geordiefella Posts: 302
    shim... no its still to big. i'll get a caliper... thanks.
    Cannondale BadBoy Rohloff
    Cannondale SuperSix / 11sp Chorus
    Ridley Excalibur / 10sp Centaur
    Steel Marin Bear Valley SE
    Twitter @roadbikedave
  • dodgy
    dodgy Posts: 2,890
    You need vernier callipers to measure, very easy to use, I have a pair (they cost about 3 quid). Maybe someone on here that lives close by can loan you some?

    Edit: Too slow :lol:
  • geordiefella
    geordiefella Posts: 302
    thanks very much cjcp. venier caliper on its way. £9. digital, new. ideal.

    much appreciated.

    happy new year to you.
    Cannondale BadBoy Rohloff
    Cannondale SuperSix / 11sp Chorus
    Ridley Excalibur / 10sp Centaur
    Steel Marin Bear Valley SE
    Twitter @roadbikedave
  • geordiefella
    geordiefella Posts: 302
    thanks dodgy.

    been going backwards and forwards to the shed to measure, order, deliver, wrong, measure, order, deliver, wrong. caliper on it way.

    thanks
    Cannondale BadBoy Rohloff
    Cannondale SuperSix / 11sp Chorus
    Ridley Excalibur / 10sp Centaur
    Steel Marin Bear Valley SE
    Twitter @roadbikedave
  • dodgy
    dodgy Posts: 2,890
    You'll find the callipers will come in handy for lots of things, good investment. I've got the digital ones too, but can't leave them in the garage as the cold gets to the batteries.
  • cjcp
    cjcp Posts: 13,345
    geordiefella wrote:
    thanks very much cjcp. venier caliper on its way. £9. digital, new. ideal.

    much appreciated.

    happy new year to you.

    No probs. :) HNY to you, too.
    FCN 2-4.

    "What happens when the hammer goes down, kids?"
    "It stays down, Daddy."
    "Exactly."
  • redvee
    redvee Posts: 11,922
    The next seatpost sizedown is 26.4mm IIRC, go to LBS and see if they've got an old one you can try for size. Mine obliged with diameter but couldn't help me on the length when I needed one for my GT frame.
    I've added a signature to prove it is still possible.
  • the_hundredth_idiot
    the_hundredth_idiot Posts: 813
    You should try retrobike. I recently bought an old Marin Pine Mountain to do up as a commuter and the guys on the retrobike forums have lots of knowledge about old MTBs. (I didn't even know I'd bought a Pine Mountain until they helped out.)
    Never be tempted to race against a Barclays Cycle Hire bike. If you do, there are only two outcomes. Of these, by far the better is that you now have the scalp of a Boris Bike.
  • supersonic
    supersonic Posts: 82,708
    Late 80s and early 90s models had 26.2mm posts.
    GT ZASKAR CARBON TEAM

    VOODOO CANZO

    Come and see me at https://www.facebook.com/biketyke/
  • desweller
    desweller Posts: 5,175
    [pedant] It's not a vernier calliper if it doesn't have a vernier scale on it [/pedant]
    - - - - - - - - - -
    On Strava.{/url}
  • geordiefella
    geordiefella Posts: 302
    well. i got the gauge. thank you everyone.

    measurements were about 26.38ish. not truely circular across the seat tube opening.

    anyway, it was 26.4" fits perfect. £12 in the end. sent the other 3 i'd previously bought back to the ebay sellers. luckily they agreed to return them.

    thanks all. winter bike up and running, studs an all! (just in time for the thaw, bo**ocks)

    :-)
    Cannondale BadBoy Rohloff
    Cannondale SuperSix / 11sp Chorus
    Ridley Excalibur / 10sp Centaur
    Steel Marin Bear Valley SE
    Twitter @roadbikedave
  • themightyw
    themightyw Posts: 409
    Out of curiosity, as I'm about to have to source a frame for a vintage frame I've just bought which doesn't have an 'existing' seatpost, I assume you measure from one side to opposite side of the tube interior?
  • SimonAH
    SimonAH Posts: 3,730
    Yes Sir.
    FCN 5 belt driven fixie for city bits
    CAADX 105 beastie for bumpy bits
    Litespeed L3 for Strava bits

    Smoke me a kipper, I'll be back for breakfast.
  • nicklouse
    nicklouse Posts: 50,675
    this is also good to know.

    http://www.bikeradar.com/forum/viewtopic.php?t=12726337
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Alphabet
    Alphabet Posts: 436
    edited November 2010
    top tip to measure it super accurately on a budget - using a cigarette paper or something equally thin, wrap at around the sdeatpost and mark the exact circumference.

    as the circumference is 2piR, reverse it back to find the radius and double this for a very accurate measurement of the diameter without and fancy tools.

    think i might have read this on here (or lfgss) but am too lazy to search for the credit - sorry:)
    Benotto SS/Fixie FCN:5
    Kona Kula FCN:9

    Looking for a cycling buddy?
  • nicklouse
    nicklouse Posts: 50,675
    Alphabet
    it is linked above. :wink:
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Alphabet
    Alphabet Posts: 436
    d'oh
    Benotto SS/Fixie FCN:5
    Kona Kula FCN:9

    Looking for a cycling buddy?
  • deptfordmarmoset
    deptfordmarmoset Posts: 3,118
    Alphabet wrote:
    top tip to measure it super accurately on a budget - using a cigarette paper or something equally thin, wrap at around the sdeatpost and mark the exact circumference.

    as the circumference is 2piR, reverse it back to find the radius and double this for a very accurate measurement of the diameter without and fancy tools.

    think i might have read this on here (or lfgss) but am too lazy to search for the credit - sorry:)

    I think you might need those king size papers to get it round a seat post. How nice of Rizla to specially design bigger papers for cyclists... :wink:
    Looking for a cycling buddy?

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