Tell me what I need to know about seatpin offset......please

fearby
fearby Posts: 245
edited April 2009 in Workshop
Some are zero degrees and some have quite an offset. Why is this? Are they zero offset ones just for time trial frames to get further forward?
The one I got with my latest purchase seems to have quite a large offset so the saddle seems to be slid quite far forward to get my correct position. Am I correct in thinking a zero offset would allow me to slide the saddle further back (and look like I know how to size a bike properly!)

:)

Comments

  • maddog 2
    maddog 2 Posts: 8,114
    you've answered your own question I suspect.

    whether you need layback depends on where you want the seat to be. For TTing this will be further forward than regular riding. Things like flexibility, thigh bone length and gorilla-ness also play a magical mystical role.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • redddraggon
    redddraggon Posts: 10,862
    I like to use a inline seatpost on 73deg seattube frames, but 74+deg frames I normally use a post with setback. It's all to with being positioned correctly in relation to the BB.
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  • Monty Dog
    Monty Dog Posts: 20,614
    It also depends on your style of riding, your flexibility and strength as well as the frame in relation to you own anatomy. On my cross bike I have a 32mm offset post and the Arione saddle right back on the rails - it means I can get my weight over the back wheel for grip on sand, gravel and mud. Many TT bikes have steep seatube angles - 75 degree plus and zero offset posts to allow a bigger angle between the pelvis and the femur, to enage a range of leg muscles in cycling. it really depends on your flexibility, strength and physiology. Generally, more set back allows you to enage the quads and glutes more effectively in the saddle - but does rely on a strong 'core' - such a position can cause lumbar problems if not accustomed to it.
    Make mine an Italian, with Campagnolo on the side..
  • fearby
    fearby Posts: 245
    Monty Dog wrote:
    It also depends on your style of riding, your flexibility and strength as well as the frame in relation to you own anatomy. On my cross bike I have a 32mm offset post and the Arione saddle right back on the rails - it means I can get my weight over the back wheel for grip on sand, gravel and mud. Many TT bikes have steep seatube angles - 75 degree plus and zero offset posts to allow a bigger angle between the pelvis and the femur, to enage a range of leg muscles in cycling. it really depends on your flexibility, strength and physiology. Generally, more set back allows you to enage the quads and glutes more effectively in the saddle - but does rely on a strong 'core' - such a position can cause lumbar problems if not accustomed to it.

    That's a very comprehensive reply thanks. Is that your own experience and opinion or is it common knowledge? Couldn't find much about seatpin offset on the internet. I cannot see how seatpin offset is going to affect position if you ultimately position the saddle exactly the same height above the bottom bracket and exactly the same distance from the bars!

    :?
  • maddog 2
    maddog 2 Posts: 8,114
    fearby wrote:
    I cannot see how seatpin offset is going to affect position if you ultimately position the saddle exactly the same height above the bottom bracket and exactly the same distance from the bars!

    it won't

    but a offset seatpost will allow you to set the seat further back than a straight one, but you're right, al posts have a fore and aft adjustability so there is some overlap between offset and zero posts.

    As a throwaway comment, I now run more offset than I used to, as I'm fitter, older, and cleverer than I was when I was a young pup.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer