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Thread: Long Seat Post

  1. #1
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    Long Seat Post

    Does anyone know a source for a 29.2mm seatpost longer than 400mm?

    It's for a KHS Westwood folding bike that I just bought at an auction. I am 6'-2" with long legs and the standard 400mm post is really too short for me.

    I have asked at the local bike shops and at KHS without success.

    Either a standard or telescoping post would be of interest.

    I would also be interested in a smaller diameter post if anyone knows of a good shim system. The only shims I have seen are about 2" long which seems to me to be a bit short for a long seat post.

    David

  2. #2
    Senior Member wahoonc's Avatar
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    David,
    Being tall and folding bikes doesn't work too well does it BTW I am 6'-3" I feel your pain. I would check on the Harris Cyclery website under special order parts and see if one is available thru Quality parts. You also might consider putting longer crank arms on too. I just got my new Kalloy 400mm post for my Raleigh R.S.W. Compact. Makes a huge difference in the ride, now that I can extend my legs. I was so anxious that I went to Target and bought a cheap saddle just so I could ride it. I have a Brooks on order but it hasn't gotten here yet. I have just gotten into the folders (don't tell my bride ) so now I am looking at other models. The Raleigh was one I have always wanted since the early 70's. Now I need one that is a bit more practical. I am looking at the Dahon Picolo D3 and a Brompton. My requirements are kind of screwy. I want a very compact package, internal gears, fenders, rack(s) and generator hub lighting How do you like the KHS other than the size?

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  3. #3
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    I know a couple of people who have 'home-converted' a too short oversize diameter seatpost to take a second stage standard diameter seatpost. Not recommending it but something to keep in mind...

  4. #4
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    Quote Originally Posted by wahoonc
    David,
    Being tall and folding bikes doesn't work too well does it BTW I am 6'-3" I feel your pain. I would check on the Harris Cyclery website under special order parts and see if one is available thru Quality parts. You also might consider putting longer crank arms on too. I just got my new Kalloy 400mm post for my Raleigh R.S.W. Compact. Makes a huge difference in the ride, now that I can extend my legs. I was so anxious that I went to Target and bought a cheap saddle just so I could ride it. I have a Brooks on order but it hasn't gotten here yet. I have just gotten into the folders (don't tell my bride ) so now I am looking at other models. The Raleigh was one I have always wanted since the early 70's. Now I need one that is a bit more practical. I am looking at the Dahon Picolo D3 and a Brompton. My requirements are kind of screwy. I want a very compact package, internal gears, fenders, rack(s) and generator hub lighting How do you like the KHS other than the size?

    Aaron
    Can't find it on the Harris website.

    I like the KHS a lot. It rides very well, is easy to fold, will take racks and guards and I like the derailler gears. Its great for putting in the trunk of a car. There are other bikes that fold into a smaller tidier package but I gather you usually lose something in ride quality.

    David

  5. #5
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    Quote Originally Posted by LWaB
    I know a couple of people who have 'home-converted' a too short oversize diameter seatpost to take a second stage standard diameter seatpost. Not recommending it but something to keep in mind...
    Sounds a bit scary but I'll think about how I might do it.

    David

  6. #6
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    The only reference to a 500mm post that I could find was the 27.2mm Kalin one used by Downtube. I don't know where you can buy it unless Downtube will sell one. It would have to be used with a shim and I found long (almost 4") 29.2-27.2 shims are made by Cane Creek and others.

    For now I have built one 510mm long by cutting off the top of an old 29.2mm post (leaving 205mm), taking a new 25.4mm x 400mm Kalloy post which was in interference fit inside the larger post, sanding the mating serfaces, applying Hysol epoxy, driving the two together and cutting off the end of the larger post that deformed when I was persuading it wiuth a large hammer. ( I guess I could have done more sanding or preheated the large tube.

    The joint has about a 3" (75mm) overlap and feels very solid. The upper tube flexes just a little with heavy load.

    The new post weighs 410g compared to the 340g original.

    The new 25.4mm post cost $C20. The old 29.2mm sacrificial post had no mating top parts and cost $2.50.

    This gets me going with a decent seat height but I'd still like to find a full 500mm 29.2 post (telescoping would be better) or make one from a 350mm 29.2 post and a shorter small dia. inner post. Either option should be a bit stiffer and give me more adjustment so that I can reset seat height to suit my wife without changing the post.

    David

  7. #7
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    I have a Downtube VIII and my seatpost broke. Downtube ageed to replace it under warranty but in the meantime I made a makeshift long seatpost with galvainzed schedule 40 pipe (threaded end). Used 3/4 inch pipe, a 3/4 to 1/2 reducer and a short 1/2 inch threaded nipple. I added a clamp-on type seat clamp to the end of the 1/2 inch pipe and then mounted my seat. The original seatpost was 27.2 mm so I needed to shim the pipe one a bit to get it to clamp firmly. It's heavy, but hey it works until my replacement from arrives from Downtube.

  8. #8
    Seņor Mambo
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    Can you give more details as to how your seatpost broke?

  9. #9
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    One option, implemented by several members of the forum, is to create a telescopic seatpost.

    Announcing: the DT FS TB

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