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Minimum seapost insertion

Discussion in 'Bicycle Mechanics and Repairs' started by Smoothhound, 13 Jun 2008.

  1. Smoothhound

    Smoothhound New Member

    Hi All,

    I've just replaced my saddle & seatpost on my hybrid (spesh sirrus). For the seat post I got the same length as my old one, but because of the different bolt size/configuration and the saddle being a bit thinner, the saddle is now slightly too low when the seatpost is at the minimum insertion.

    So what I want to know is how risky is it to have the seatpost out a little bit further - I reckon even 5 - 10 mm might make all the difference. I'm thinking that the minimum mark is calculated for a rider of a certain weight perhaps?

    I could sent it back of course and get the next size up - I'm basically looking for the lazy way out, I can't bear to put my old creaky loose suspension post back on for a few more days while I wait :rolleyes:

    Cheers
     
  2. bobg

    bobg Über Member

    Location:
    Crosby Merseyside
    I've no doubt that you'll here opposing views about this one but I'd have no hesitation about going 5 - 10mm over the recommended line and have done on any occasions over the years... so far the sphincter/prostate remain intact :rolleyes: but having said that, what length is/will be in the frame ?
     
  3. OP
    OP
    Smoothhound

    Smoothhound New Member

  4. kyuss

    kyuss Über Member

    Location:
    Edinburgh
    I would be happy to run it a bit higher than minimum insertion, the post should be strong enough to take it. The thing you really need to watch for is that the very bottom of the post goes down past the bottom of the top tube by quite a bit (10-20mm at least). I ran a post that was a bit too short in this respect. Result, too much leverage on the top of the seat tube and a cracked frame at the point the seat tube meets the top tube.
     
  5. fossyant

    fossyant Ride It Like You Stole It!

    Location:
    South Manchester
    You should be OK - see how much of the post is below the marker - it's normally lots.....
     
  6. OP
    OP
    Smoothhound

    Smoothhound New Member

    Ok, there is exactly 100mm below the minimum mark which I think get's it plenty below the top tube join (I'll have to double check Monday - the bike mainly lives in Marylebone station) so unless I hear any horror stories I reckon I'll go for it.

    Thanks for all the responses :biggrin:
     
  7. fossyant

    fossyant Ride It Like You Stole It!

    Location:
    South Manchester
    100mm fine...........

    The poor thing lives at a station, not at home in the evening..oh the poor bike......

    Thank god I don't live anywhere near London...my bikes live with me, locked up dry and warm.. ONLY KIDDING FELLA.... don't worry too much if it lives away from home - it will or won't be there tomorrow !!!!
     
  8. OP
    OP
    Smoothhound

    Smoothhound New Member

    ;) Yes it doesn't sound good does it! however, they have quite a good scheme in operation there where you can register your bike (free to season ticket holders) and it gets to live behind the ticket barrier, under cover, under CCTV, I take it back home once a fortnight or so for a bit of clean/tune up. It suits me better than a foldie!

    Anyway, seatpost is now 10mm over the limit and the base looks to my eye least 20mm below bottom of top tube, and crucially: it's much comfier. Jobsagoodun, cheers again all.