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  1. #1
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    Madone 5 Series Seatmast issues. The clamp won't stay put!!! Suggestions?

    I've been through 2 replacement seatmasts and several clamp assemblies. The clamp assembly has been updated what looks like 3 times since it launched. Each change in the clamp assembly seems to be an improvement. However, no matter how hard (within reason) I clam the assembly it still slips backwards after a while, usually after I hit a good bump. Causing the nose to tip way up and being very unsettling in general.

    I have tried several methods of getting the clamp assembly to stay put but nothing seems to work. Originally the assembly came greased. After my first saddle change it started being a problem soon after. I tried completely cleaning the grease off and that worked better but not good enough. I had to clamp and reclamp the thing so many times the bolt stripped and it was a TOTAL PAIN to get the clamp loosened.

    The latest test was using carbon friction past and the latest version of the clamp assembly which now comes in a 'wide' model for seats with wide rails ala Selle Italia Carbon. I've clamped the thing so tight it has put small dents in the carbon rails which really sucks but it still won't stay put. Argh!!!

    Maybe I'm just to heavy at 200lbs. I don't have the seat set too far back as to cause to much leverage on the clamp either. At this point I don't know what to do. I am fed up with this clamp and it really the only weak link the bike.

    Any suggestions??? Does anyone know of an after market mast cap like the ones made by Ritchey or others that may fit? I'll try anything at this point.

  2. #2
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    Torque Wrench

    On my older carbon Trek, the bolts on the upper frame (stem and seat post clamp) should be tightened to 50 to 55 inch pounds but the seat clamp can be tightened to 150. Don't take my word for it; get the torque specifications from Trek and tighten the bolt to spec. The threads of the bolt in your seat clamp should be greased. Never tighten any bolt on any carbon frame or part without a torque wrench. A torque wrench is also needed for the pinch bolts on your crank and other components. If there is more than one bolt, tighten them slowly and evenly to the required torque. I have three torque wrenches: an automotive one for bottom bracket installation (40 foot pounds?), a lever type and a Park Tools click type. I recommend the Park Tools one. I tighten every bolt to spec with a torque wrench and I use either grease, locktite or anti-seize lubricant on the threads.

    You could also take it to your dealer.

  3. #3
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    I am having similiar problems with my trek 5 series madone. Except mine is a little more severe. I have had the bolt on the seat mast clamp break 3 times over the last year. Each time I take it back to my dealer and they fix it. Trek has denied their are any design flaws in the bike and has sent new seat mast as a fix. Needlesss to say like you, I have become increasingly frustrated and somewhat fearful of my bike. It is a severe jolt when the bolt breaks and the seat mast drops to the bottom.
    I like my bike a lot and am a frustrated that a .50 cent part keeps breaking and is taking all the fun out of riding this great bike!

  4. #4
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    Quote Originally Posted by Mhoyle329
    ...I have had the bolt on the seat mast clamp break 3 times over the last year...
    50 inch pounds is not very tight. Do you use a torque wrench? The bolt can probably take 200 inch pounds before it breaks.

  5. #5
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    I am only talking about the single 5mm bolt that clamps the seat on the to the seat mast assembly. This assembly is used to adjust the position of the seat as well.

    One thing I just read on Trek's website is saying you need to 'GREASE" the cups that make up the clamp assembly. They say it allows the cups to fully 'SEAT' and as a result stay clamped.

    I'm going to try and use grease ONE more time. I have not used grease for awhile thinking it was counter intuitive but that exactly what Trek is saying you should do and they specifically say do NOT use carbon grip paste either. Problem is my bolt stripped out while trying to torque it back in place on my ride yesterday after it slipped again. Now I have to go get another bolt.

  6. #6
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    Quote Originally Posted by wirelessness
    ...Problem is my bolt stripped out while trying to torque it back in place on my ride yesterday after it slipped again. Now I have to go get another bolt.
    If it stripped, you over-torqued it and it's possible that the threads in the clamp are stripped as well. Do I need to say "torque wrench" again?

  7. #7
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    Quote Originally Posted by Tlaloc
    If it stripped, you over-torqued it and it's possible that the threads in the clamp are stripped as well. Do I need to say "torque wrench" again?
    If the freaking clamp would hold the saddle in place at the specified torque setting then I would have never started this thread!!!

    Like I said, an updated FAQ on the Trek Website says to use grease and NOT carbon friction paste. So I got one more clamp assembly kit with a new bolt and am going to try it with grease this time and see if it holds. If not, I don't know what to do.

  8. #8
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    The clamp seems to be holding better using grease rather than carbon grip paste for now. I am still having to torque the bolt down pretty hard but not as hard as before and it did not slip at on my last hard ride.

  9. #9
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    The clamp held OK for several rides after converting from carbon grip paste to high quality grease to lubricate the cups. It did finally pop loose sending the nose higher when I hit a hard bump on my last drive. As is what always happens, after trying to tighten it enough to get home the bolt started to strip out. This is getting very old.

    Does anyone know if there is an after market mast cap that could fit the oval style 2008 Madone seatmast riser?

  10. #10
    zac
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    Quote Originally Posted by wirelessness
    I've been through 2 replacement seatmasts and several clamp assemblies. The clamp assembly has been updated what looks like 3 times since it launched. Each change in the clamp assembly seems to be an improvement. However, no matter how hard (within reason) I clam the assembly it still slips backwards after a while, usually after I hit a good bump. Causing the nose to tip way up and being very unsettling in general.

    I have tried several methods of getting the clamp assembly to stay put but nothing seems to work. Originally the assembly came greased. After my first saddle change it started being a problem soon after. I tried completely cleaning the grease off and that worked better but not good enough. I had to clamp and reclamp the thing so many times the bolt stripped and it was a TOTAL PAIN to get the clamp loosened.

    The latest test was using carbon friction past and the latest version of the clamp assembly which now comes in a 'wide' model for seats with wide rails ala Selle Italia Carbon. I've clamped the thing so tight it has put small dents in the carbon rails which really sucks but it still won't stay put. Argh!!!

    Maybe I'm just to heavy at 200lbs. I don't have the seat set too far back as to cause to much leverage on the clamp either. At this point I don't know what to do. I am fed up with this clamp and it really the only weak link the bike.

    Any suggestions??? Does anyone know of an after market mast cap like the ones made by Ritchey or others that may fit? I'll try anything at this point.

    Any suggestions? Certainly, get up off your saddle when you are approaching bumps.

    Your saddle IS NOT a seat! Even though it can support your full weight, this is really not its intended purpose. If you are hitting bumps and keeping your full weight on the saddle, things like this are going to happen.

    This is particularly evidenced by the fact that you have gone through a couple of seat mast caps without the problem being resolved.

    HTH
    zac

  11. #11
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    @Zac,

    The fact that Trek felt compelled to add a section about this in their FAQ recently is pretty clear I am NOT The only person having trouble with this clamp assembly. Hopefully, I can get it sorted somehow. In the meantime I will strive to be as skilled a rider as yourself who can ride any road whilst never getting caught off guard by a single bump.

  12. #12
    zac
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    You know you are the one who asked for suggestions. These forums are a great place to learn how to ride and ride better, and maintain your bike.

    You clearly have no idea what you are doing with respect to tightening the saddle clamp, as you admittedly have crushed the saddle rails. You most likely have bent the clamp fingers too and not just on one assembly, but apparently on multiple ones.

    Generally multiple failures of the same part point to either a defective run, or user error.

    To me your explanation fits within the user error category on at least two levels.

    If you don't want the advice don't ask for it.

    I strongly suggest that you have your next adjustment done by your LTD, as you demonstrate a failure to comprehend simple advise.

    Good luck to you wirelessness. I truly hope you solve this issue, but you have to be open to the possibility that you are doing it wrong

    zac

  13. #13
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    @zac,

    I am looking for advice and some of yours is useful. Some of it is speculative based on facts not in evidence. This is not my first bike, but it is the first bike I've ever had this sort of problem with. You are probably right that poor technique could be exacerbating the issue but it's hard agree with that 100%.

    It's not rocket science to tighten the bolt to spec using a torque wrench. I am positive I have done that correctly many times. There would be no problem with over tightening if the clamp would stay put at the specified amount of torque. The clamp ears are NOT bent and have never been bent. I'm fairly mechanical and have had no problem taking many other parts of my bike on and off.

    That said, I will try very hard put less weight on the seat after replacing the bolt one more time. I just find it hard to believe that can be the sole cause of this problem. There are tons of people buying this bike who weigh more than me and have less experience as well.

  14. #14
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    wirelessness is totally in the right - My new Giant Defy 2015 SL1 uses the same crappy design - a single bolt that via friction is supposed to maintain the angle of the seat. If you sit on anywhere other than dead centre - like on the nose....the seat will angle down!

    I've taken apart the seat mast and I was severly dissappointed that it doesn't have any notches or serrations to help hold the seat angle - it truly just rely on pure friction between the tightening bolt. What a truly truly dumb design for something from the 21st Century.

    This single bolt design is used by Giant and Trek - not because it's a great design but only because Trek is made by Giant. So maybe someone's relative in Giant managment - a recent graduate from some technical school came up with the idea and got it implemented across the 2 brands. If i ever met the fellow i'll give him a kick in the in-between.
    Last edited by machoman; 2 Weeks Ago at 03:05 AM. Reason: addit

  15. #15
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    Quote Originally Posted by wirelessness View Post
    @zac,

    I am looking for advice and some of yours is useful. Some of it is speculative based on facts not in evidence. This is not my first bike, but it is the first bike I've ever had this sort of problem with. You are probably right that poor technique could be exacerbating the issue but it's hard agree with that 100%.

    It's not rocket science to tighten the bolt to spec using a torque wrench. I am positive I have done that correctly many times. There would be no problem with over tightening if the clamp would stay put at the specified amount of torque. The clamp ears are NOT bent and have never been bent. I'm fairly mechanical and have had no problem taking many other parts of my bike on and off.

    That said, I will try very hard put less weight on the seat after replacing the bolt one more time. I just find it hard to believe that can be the sole cause of this problem. There are tons of people buying this bike who weigh more than me and have less experience as well.
    according to zac a rider never has their vision obscured and never hits a bump hard? C'mon, there's a reason that simple components like Thomson seat posts are celebrated while similar components are reviled. Because they work.

    The seatpost has a straightforward function. Apparently Trek's and Giant's aren't up to the task.

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