Solving a seat post problem

... or Not All Posts Are The Same Size

Last update 25th January 2008

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Phil Deaves, Swindon, Wiltshire

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Our son, desperate to ride his new Felt F24, is pleased that he can now do so.  However, first the saddle had to be lowered below the minimum height available using the supplied saddle and seat post (pictured).  By using an older saddle and post from the spares tub (the latter robbed from an old Raleigh three-speeder, I believe), I was able to invert the mounting points (rather like a capital D shape) and fit that.  That is when the next problem manifested itself.  The post was too thin for the tube in which it had to fit.  There was no way that the clamp would be able to tighten enough without causing permanent damage.  I had no idea that different posts were different sizes.  I have since learnt that there are numerous different sizes, many almost but not quite the same.

Much head-scratching ensued.  How does one fit and fasten a narrow post into a wider tube?  I tried wrapping the post with electrician's tape, but that just caused a gooey mess when the bike was ridden, as the saddle still rotated.  Casting my eyes around the house for ideas I came across the perfect shim:

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... a 35mm film pot!  I removed the pot's base and lid, and a lengthwise slice to make C-shaped tube.  This could be coiled up to a smaller diameter than the original pot.  This was placed around the seat post with the small "lip" at the top, and the whole lot pushed into the bike.  This was a perfect fit, and the "lip" prevents the pot from disappearing permanently inside the bike frame.  The clamp tightens nicely and holds the saddle firmly in place, the overall result being that the bike can be, and is, ridden and enjoyed.  Once the time comes for raising the saddle, the original components can be refitted.

In the mean time, this was a quick and easy conversion that cost nothing.  Even if you need to buy a 35mm film especially for the job, it would undoubtedly be cheaper than most alternatives.  If only all jobs were this quick, easy and cheap!