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  1. #1
    Senior Member swc7916's Avatar
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    Suspension Seatpost Failure

    This was an unexpected failure: Karen and I had just finished our ride on Saturday and as she was dismounting the bike the stoker's seat fell off! It turns out that the head of the seatpost is just pressed onto the post and it had worked itself off. It's a good thing we were at the end of the ride instead of being stranded in the middle. What scares me most is what could have happened if it occurred while we were riding.

    This was a Tamer PivotPlus. We got it with our Rodriguez tandem and it has about 2,500 miles on it. I took the post back to R+E and since they didn't have another Tamer in 25.4mm, Scott gave me a Crane Creek ThudBuster to try. I hope that Karen likes the ThudBuster because it looks more trouble-free to me: The base of the head is a machined part of the post - it is not pressed on - and there are fewer moving parts. I have heard of cases where the elastomer insert ruptured, but I hope that sort of failure would not be catastrophic. The Tamer design is always under spring tension and depends on a friction fit to keep the head on.
    Last edited by swc7916; 03-18-09 at 08:42 AM.

  2. #2
    Senior Member zonatandem's Avatar
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    While we do not use a suspension seatpost for stoker, we have test ridden several. The Thudbuster (in my stoker's opinion) was the best after the Allsop c/f beam.
    Someone can always make something cheaper and the Tamer failure proves that point.

  3. #3
    Senior Member swc7916's Avatar
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    Quote Originally Posted by zonatandem View Post
    Someone can always make something cheaper and the Tamer failure proves that point.
    I don't know that the Tamer is cheaper - it's just a different design. My concern - now that I know about it - is that the spring inside the seatpost pushes up against the suspension mechanism, which is a press-fit on the seatpost.

  4. #4
    Senior Member antiquepedaler's Avatar
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    Quote Originally Posted by zonatandem View Post
    While we do not use a suspension seatpost for stoker, we have test ridden several. The Thudbuster (in my stoker's opinion) was the best after the Allsop c/f beam.
    Someone can always make something cheaper and the Tamer failure proves that point.
    Interesting! My stoker hated the Thudbuster because it moved down and back, effectively moving her away from from the pedals with each depression, rather than the Tamer which just goes down. So the Tamer is on it's 7th year.
    [SIGPIC][/SIGPIC]

    Antique Pedaler

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  5. #5
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    I don't know. The Tamer Pivot plus that we have has a paralelogram shape that moves the seat back once it is depressed as to not to drastically change the distance from the seat to the pedals. Ours failed, collapsed, after 15K miles

  6. #6
    Senior Member
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    Quote Originally Posted by swc7916 View Post
    I hope that Karen likes the ThudBuster because it looks more trouble-free to me: The base of the head is a machined part of the post - it is not pressed on - and there are fewer moving parts. I have heard of cases where the elastomer insert ruptured, but I hope that sort of failure would not be catastrophic. The Tamer design is always under spring tension and depends on a friction fit to keep the head on.
    FWIW: the Thudbuster's head used to be pressed on. Several years back they switched to the machined head because too may Thudbusters lost their head

    Friends of us have had a telescopic Tamer fail some years ago: the 'rod' that actually carries the saddle snapped.
    Regards, Marten / www.tandemclub.nl
    '03 Santos Dual Travel | '13 MSC Zion Tandem

  7. #7
    Senior Member
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    We had continual problems with Tamer seatposts and gave up on them. When we contacted Tamer their response was "you are the only ones that have had that problem."

    Sheldon and Martha

  8. #8
    Bikaholic blamp28's Avatar
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    We have a Thudbuster and my stoker loves it. It sure looks like a solid design.
    Trek Fuel XC MTB, Giant OCR Road Bike, Rans Screamer - Tandem

  9. #9
    Time for a change. stapfam's Avatar
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    Had a thudbuster on since 2004- and it is an offroad tandem. No problems and I wouldn't use anything else.
    How long was I in the army? Five foot seven.


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  10. #10
    Senior Member brewer45's Avatar
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    Stoker Malkin says +1 on the Thudbuster. She also uses a much stiffer insert than suggested for her weight so the thing doesn't bounce at all--it just provides firm damping for the hard hits (which, of course never happen because I'm such a competent captain...)

    Cheers!
    Last edited by brewer45; 01-20-09 at 08:55 PM. Reason: Fix typo
    2008 Red Co-Motion Speedster Co-pilot (Redster)
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  11. #11
    Senior Member swc7916's Avatar
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    Quote Originally Posted by antiquepedaler View Post
    Interesting! My stoker hated the Thudbuster because it moved down and back, effectively moving her away from from the pedals with each depression, rather than the Tamer which just goes down. So the Tamer is on it's 7th year.
    The Tamer PivotPlus is a parallogram design similar to the the ThudBuster; it's just that the spring design is different. The Tamer uses a spring and a piston inside the seatpost whereas the Thudbuster uses an elastomer "puck" inside the parallogram mechanism. According to my stoker, the Thudbuster bounces more and is harder on her sitbones; the Tamer "floats" and the bumps don't hit her as hard. I'm guessing that the force required to compress the Thudbuster is non-linear - that is, it gets stiffer the more it's compressed - whereas the spring in the Tamer exerts a more constant force. It also appears to me that the Tamer has more travel.
    Attached Images Attached Images

  12. #12
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    What we like about the Tamer is the ability to set the force required for actuation. Properly set for the weight of the ridder, the seat does not float. It only actuates when a critical force is reached.

  13. #13
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    Quote Originally Posted by cornucopia72 View Post
    What we like about the Tamer is the ability to set the force required for actuation. Properly set for the weight of the ridder, the seat does not float. It only actuates when a critical force is reached.
    Our Thudbuster LT has an adjustment for pre-loading which sets the activation force. It also came with a selection of inserts that can be mixed or matched for six firmness adjustments. There are even more inserts available for an extra light person.

    I understand the Thudbuster ST is much more limited.
    Last edited by rfutscher; 01-21-09 at 04:30 PM.

  14. #14
    Senior Member
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    Stoker loves her thudbuster ST.

    She used to hate the original suspension post as it kept "bouncing" when we put the power on

  15. #15
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    My stoker has used the PivotPlus for many years and is very happy with it once it is adjusted properly. The pins wear out after a while. I contacted Tamer - they had me ship it back and they replaced the pins for a reasonable charge. It's been working fine ever since (> 1 year).

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