Seat Post Slipping is it my custom frame?- Mtbr.com
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  1. #1
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    Seat Post Slipping is it my custom frame?

    Seat Post Slipping is it my custom frame?-img_1400.jpg

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    Hey guys, sorry I accidentally posted without my text. So my question for you frame builders is this, I got a really expensive titanium frame from a builder and its been great except no matter what i do I cannot get the post to stop slipping. Ive tried many different posts, and seat post collars, Ive found the ones that are double clamps, two different diamters keep it from slipping but then they creak constantly. Im wondering is my seat tube just to small for my post? in other words did the company I bought my frame from mess up on QC and send a frame out thats to large for the 31.6mm seatpost size they claim? it measures with my digital caliper at 31.8, I took many different measurements and I'm pretty confident this is the actual inner diameter. I don't know what they are supposed to be but I figure you all might know if this is right? or do i need to try and get a warranty replacement for my frame since it has a life time warranty? I appreciate your help, the builder is half way across the world unfortunately so i wanna make sure I've tried everything before having to go the replacement route.

  3. #3
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    Good slip fit for your post would be in the ballpark of 31.65 or so, not 31.8. That said, calipers are a terrible way to measure the ID of anything accurately. Does the post jiggle in the frame when the clamp is loose/fall down into the frame? If so, frame is out of spec.

    I might try a coke can shim before shipping it around the world, but that's just me. Assuming you measured it accurately, you certainly have a valid warranty claim, IMO.

    -Walt

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    Quote Originally Posted by Walt View Post
    Good slip fit for your post would be in the ballpark of 31.65 or so, not 31.8. That said, calipers are a terrible way to measure the ID of anything accurately. Does the post jiggle in the frame when the clamp is loose/fall down into the frame? If so, frame is out of spec.

    I might try a coke can shim before shipping it around the world, but that's just me. Assuming you measured it accurately, you certainly have a valid warranty claim, IMO.

    -Walt
    I have tried the coke can shim and it still slipped but I only tried it once, i will try it again to see, just frustrates me spending nearly 4 grand for a frame and having to use a can in my seatpost! It doesn't jingle when i put it in the frame without a clamp, but it certainly slips down when I let it go, and yes the caliper isn't ideal, but I couldn't think of any other way to measure it accurately on the inside diameter.

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    Quote Originally Posted by Fattyrider38 View Post
    I have tried the coke can shim and it still slipped but I only tried it once, i will try it again to see, just frustrates me spending nearly 4 grand for a frame and having to use a can in my seatpost! It doesn't jingle when i put it in the frame without a clamp, but it certainly slips down when I let it go, and yes the caliper isn't ideal, but I couldn't think of any other way to measure it accurately on the inside diameter.
    I have had a similar problem in the past, though it was an undersized ti seat post. it was only 0.1mm diameter out, but it still gave me a headache. in the end I used plastic shim stock, which allows mounting the seat post dry and therefore less likely to slip, but still maintains a barrier to corrosion and it has been silent in my experience.

    this is the stuff I have used (blue, very thin - o.o5mm the other colours are thicker so you need to work out what you need), cut into the right size rectangle and then wrap around post, tape around the top and carefully push into frame so shim stock stays flat. it is tricky to do but works well.

    its not ideal, but it might be worth a try. oh, and a salsa liplock!

  6. #6
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    Thanks for the info, i noticed the currency is foreign, how long did it take for you to get one of these after ordering? I will definitely try it, the difference in my post to tube is about 1.5mm but ya its just enough to be a major PItheA!

    Quote Originally Posted by dRjOn View Post
    I have had a similar problem in the past, though it was an undersized ti seat post. it was only 0.1mm diameter out, but it still gave me a headache. in the end I used plastic shim stock, which allows mounting the seat post dry and therefore less likely to slip, but still maintains a barrier to corrosion and it has been silent in my experience.

    this is the stuff I have used (blue, very thin - o.o5mm the other colours are thicker so you need to work out what you need), cut into the right size rectangle and then wrap around post, tape around the top and carefully push into frame so shim stock stays flat. it is tricky to do but works well.

    its not ideal, but it might be worth a try. oh, and a salsa liplock!

  7. #7
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    where are you? id bet there is a closer to home option to buy?

  8. #8
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    if really 31.8 that is way too big.
    "Put your seatbelt back on or get out and sit in the middle of that circle of death." - Johnny Scoot

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    Utah, and yes there were closer options, however I wanted a frame that had a pinion gearbox which takes a proprietary frame, at the time the american builders didn't have their models out yet ,so thats why I went over seas, learned my lesson though.


    Quote Originally Posted by dRjOn View Post
    where are you? id bet there is a closer to home option to buy?

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    Have you tried carbon paste?(Park is just one example, there are plenty of other manufacturers)

    You could try that by itself or in addition to the beer can shim. Either of which could work on its own, but probably better together.

    You could also get a custom shim made to go down to a 30.9mm post.

    Agree that this is frustrating, but just trying to offer solutions if the builder proves to be tough to work with.

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    My buddy uses one of these and has been very happy with it. (His 27.2 thomson was undersized, measured 27.10)

    https://www.ebay.com/sch/i.html?_fro...LH_TitleDesc=0

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    Quote Originally Posted by Feldybikes View Post
    Have you tried carbon paste?(Park is just one example, there are plenty of other manufacturers)

    You could try that by itself or in addition to the beer can shim. Either of which could work on its own, but probably better together.

    You could also get a custom shim made to go down to a 30.9mm post.

    Agree that this is frustrating, but just trying to offer solutions if the builder proves to be tough to work with.
    the other option is to do some sums and work out if say a cane creek or USE shim of a different size wouldf work to resize: i had an alu road bike that i wasnt pleased with the bore of the seat tube for 31.6 so used a shim to resize to 30.9, but used a 31.6 ID shim and trimmed off some of the circumference - id have to go back and work it out again, but it worked a treat too...

    oh and IME carbon paste in ti frames is a recipe for creaks...i use morgan blue aquaproof paste

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    I'd tend to agree with Walt, I'd tried a soda can shim, but when you install it, do so with some carbon paste, this will help stop any slipping. Make sure that you cut the shim at least 4" in length and to stop it slipping down into the frame you can roll the lip out over the top of the ST. The other alternative is to buy a 30.9 post and use a "proper" shim from a legit manufacturer, being thicker it might work better - again use carbon paste to assemble.

    Really sucks for what you say you paid for the frame, so definitely let them know about your issue, but if this simple fix will work, it's the way I'd go instead of being without the frame for a good while.
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    For those of you out there that have tries using a shim, and a smaller size post, does it seem to cause more creaking issues than not? I have avoided this option simply because I didn't want to trade a seatpost slipping problem with a creaking problem, both of which are frustrating and annoying! I tried one of those seatpost clamps that clamp around the tube and the post with two bolts, but no matter how much grease or carbon paste i use the damn thing creaks constantly with every pedal stroke. it definitely stops the post from slipping though! lol
    Quote Originally Posted by LyNx View Post
    I'd tend to agree with Walt, I'd tried a soda can shim, but when you install it, do so with some carbon paste, this will help stop any slipping. Make sure that you cut the shim at least 4" in length and to stop it slipping down into the frame you can roll the lip out over the top of the ST. The other alternative is to buy a 30.9 post and use a "proper" shim from a legit manufacturer, being thicker it might work better - again use carbon paste to assemble.

    Really sucks for what you say you paid for the frame, so definitely let them know about your issue, but if this simple fix will work, it's the way I'd go instead of being without the frame for a good while.

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    yeah I've tried carbon paste as well as grease etc, i originally had a thompson post, which slipped the worst, then switched to a fox transfer and it is a better fit but still slips, but yes thompson posts are the worst as far as the ribs like texture and they usually are a half to quarter mm off on actual size.
    Quote Originally Posted by Feldybikes View Post
    Have you tried carbon paste?(Park is just one example, there are plenty of other manufacturers)

    You could try that by itself or in addition to the beer can shim. Either of which could work on its own, but probably better together.

    You could also get a custom shim made to go down to a 30.9mm post.

    Agree that this is frustrating, but just trying to offer solutions if the builder proves to be tough to work with.

  17. #17
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    This is what happens when builders use adjustable reamers. Not a well made frame.

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    Well, actually, this is how Kona sets up the Unit stock to fit a 31.6mm post, they use a 35mm steel tube that's quite thin and then use an alu shim between the frame and post. I used my 30.9 9point8 dropper in the Unit earlier this year for a good few months and it worked great, might have had the very occasional creak which was solved by a careful clean/grease, but never anything that drove me nuts and I'm a person that hates to hear any noise coming from a bike.

    Quote Originally Posted by Fattyrider38 View Post
    For those of you out there that have tries using a shim, and a smaller size post, does it seem to cause more creaking issues than not? I have avoided this option simply because I didn't want to trade a seatpost slipping problem with a creaking problem, both of which are frustrating and annoying! I tried one of those seatpost clamps that clamp around the tube and the post with two bolts, but no matter how much grease or carbon paste i use the damn thing creaks constantly with every pedal stroke. it definitely stops the post from slipping though! lol
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  19. #19
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    Quote Originally Posted by pvd View Post
    This is what happens when builders use adjustable reamers. Not a well made frame.
    Nah, you can use adjustable reamers just fine. I've done like 750 frames that way.

    This is builder error, not the fault of the tool.

    The problem is just that someone either started with a tube that had too big of an ID or else someone reamed it WAY past where it should have been.

    -Walt

  20. #20
    pvd
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    Adjustable reamers cut tapered holes. They're garbage.

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    I should know better than to argue about this so I'll just say this:

    For the beginners reading - if you understand how the tool works, an adjustable reamer is perfectly fine for reaming seat tubes.

    -Walt

  22. #22
    SMR
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    On a Ti or steel frame how high can you go on the seat post clamp torque? Usually itís around 5nm how much higher can you go?

  23. #23
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    Quote Originally Posted by SMR View Post
    On a Ti or steel frame how high can you go on the seat post clamp torque? Usually itís around 5nm how much higher can you go?
    usually the limit is with dropper posts. the mechanisms are sensitive to pressure from the clamp. if i think about that, and why the lower portion of droppers must therefore deform so easily, it sort of worries me...

    with 9point8 that is 6nM - the highest i found when i was researchng. Thomson is 5nM iirc. as for how high *the frame* will take, id wager its more to do with when the post gets damaged - esp as usually the collars are removable...

    look up the pvd/Engin seatpost collar - i wish more collars like that were available aftermarket - spreading the clamping force over a bigger surface area makes a lot of sense.

    Ties that bind | Peter Verdone Designs

    and again - morgan blue aqua paste is the shizzle for seat posts!

  24. #24
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    Thanks dRjOn Iím referring more to a steel/ti frame with a regular post. Iíve heard you can go higher than 5nm but not really how much higher.

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    i use 6.5nm in ti or steel (or alu!) frames with alu or ti posts... if that helps!

  26. #26
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    I don't generally have to clamp the crap out of any of my frames, but I definitely think I do mine down more than 5Nm on my Monkey, depending on which post I'm using. As dRj0rn said, it's when/if the post will fail, not really the frame, not unless you tried something really silly like running a 28.6 post in a frame designed for a 31.6 with just a single layer, soda can shim.

    Quote Originally Posted by SMR View Post
    Thanks dRjOn Iím referring more to a steel/ti frame with a regular post. Iíve heard you can go higher than 5nm but not really how much higher.
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  27. #27
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    Quote Originally Posted by LyNx View Post
    I don't generally have to clamp the crap out of any of my frames, but I definitely think I do mine down more than 5Nm on my Monkey, depending on which post I'm using. As dRj0rn said, it's when/if the post will fail, not really the frame, not unless you tried something really silly like running a 28.6 post in a frame designed for a 31.6 with just a single layer, soda can shim.
    .
    My Thomson post fits snug but I canít get it to stop slipping. Like the OP Iíve tried different posts and clamps. Carbon paste instead of grease etc. Would flipping the clamp around so the gap is opposite of the seat tube slot help? I donít think I could get any sort of a shim in there.

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    I really think thompson posts, due to the weird texture they have on them, and i measured mine which was a little smaller that 31.6 makes them a prime candidate for slippage issues, almost every complaint i found while researching solutions online the poster was using a thompson post. I actually tried to get a warranty replacement for mine, but because of the slippage issue, the serial number had rubbed off (they are very light anyways originally) and I couldn't give the guy the number so they refused to warranty my post. But my issue is the frame too, because i tried other posts and still had the same issue ( i think my post measured like 31.2 on my digital caliper
    Quote Originally Posted by SMR View Post
    .
    My Thomson post fits snug but I canít get it to stop slipping. Like the OP Iíve tried different posts and clamps. Carbon paste instead of grease etc. Would flipping the clamp around so the gap is opposite of the seat tube slot help? I donít think I could get any sort of a shim in there.

  29. #29
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    I run a Thomson post on my rigid UNIT and have had no issues with it slipping, but, as said, Kona does it different and run an alu shim in the frame, so not sure if that's why I don't have trouble. Always ran Thomson before droppers became "the thing" and never had slipping issues, all again in alu frames.

    On the Unit the clamp is opposite to the frame cut, but on all other frames it's been clamp and cut on the same side without issues. Maybe just try some tin foil if the fits is too tight for a soda can shim, see if maybe that little bit of interference will do the trick. If that doiesn't work, maybe copper paste.

    Quote Originally Posted by SMR View Post
    .
    My Thomson post fits snug but I canít get it to stop slipping. Like the OP Iíve tried different posts and clamps. Carbon paste instead of grease etc. Would flipping the clamp around so the gap is opposite of the seat tube slot help? I donít think I could get any sort of a shim in there.
    One day your life will flash before your eyes, will it be worth watching??

  30. #30
    SMR
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    LyNx
    This is my only frame to ever have this issue. Any sort of shim wouldnít fit. I did a mix of carbon paste and grease today and it only slipped a mm or so. Carbon paste only or dry and it creaks. The seat tube slot doesnít go that far down compared to other frames Iíve had Iím wondering if this contributes to this problem.

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    Quote Originally Posted by SMR View Post
    LyNx
    This is my only frame to ever have this issue. Any sort of shim wouldnít fit. I did a mix of carbon paste and grease today and it only slipped a mm or so. Carbon paste only or dry and it creaks. The seat tube slot doesnít go that far down compared to other frames Iíve had Iím wondering if this contributes to this problem.
    I'm destruction incarnate, but my experience is that if there's slip without ridiculous torque i'll crack the seat tube eventually. I'll happily shim one side of a post if i can jam a slice of aluminum can down there.


    I do sleeved seat tubes or double clamps on my own frames, fwiw. (integrated clamps)

    Pvd's seat collar is awesome. https://www.peterverdone.com/ties-th...n-seat-collar/

    The soma vice is another option.
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  32. #32
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    This is more what I was talking about, a sliver of a shim might be all it takes to stop the slipping, would go this route over a grease/carbon paste route. Another thing you could try is to apply a very thin layer of something like nail polish or such inside the tube and see if that works, just make sure that you clean the inside of the tube properly with something like acetone and then you can use sand paper to bring the thickness down if it's too thick initially. The other option, depending on the STs wall thickness might be to get it reamed out so you can use a full/proper shim.

    Quote Originally Posted by scottzg View Post
    I'm destruction incarnate, but my experience is that if there's slip without ridiculous torque i'll crack the seat tube eventually. I'll happily shim one side of a post if i can jam a slice of aluminum can down there.
    One day your life will flash before your eyes, will it be worth watching??

  33. #33
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    KCNC make a device to stop seatposts slipping. They come in lots of colours/sizes and are cheap-

    http://m.ebay.co.uk/itm/130955317708
    Last edited by fxrextreme; 10-01-2018 at 10:01 PM. Reason: Missed something

  34. #34
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    Quote Originally Posted by fxrextreme View Post
    KCNC make a device to stop seatposts slipping. They come in lots of colours/sizes and are cheap-

    http://m.ebay.co.uk/itm/130955317708
    .
    Interesting, what stops the slippage the two o-rings?

  35. #35
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    it integrates with a frame collar. one clamp around post, which is tightened by the one around frame. they also make a one part collar with 2 diameter clamps. i did the same, but with separate clamps - basically a shimmed smaller id round the post - when i rode fixed off - you tend to sit and bounce quite a lot - or at least i did! worked pretty well. i still think 2 bolt clamps around frame are the way of the future w droppers as the surface area of clamping is so much greater.

    Seat Post Slipping is it my custom frame?-7.jpg

  36. #36
    SMR
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    I was actually able to get a small beer can shim in between the post and seat tube. Two days riding and no slip, no creaks. Pretty happy. Nice to ride a bike with no issues and is totally quiet. Thanks for the tips everyone. Cheapest and easiest fix ever,
    and I am torquing the seatpost collar to spec instead of a few nm's over.

  37. #37
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    Quote Originally Posted by SMR View Post
    I was actually able to get a small beer can shim in between the post and seat tube. Two days riding and no slip, no creaks. Pretty happy. Nice to ride a bike with no issues and is totally quiet. Thanks for the tips everyone. Cheapest and easiest fix ever,
    and I am torquing the seatpost collar to spec instead of a few nm's over.
    Good to here you found a solution. Iím having the same slippage issue and will try this solution. How long and wide did you make the shim?
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    I also ended up going with a small red bull can shin and I havenít had any more issues it barely fit in there but seems the fix the creaking and slipping problem.

  39. #39
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    Quote Originally Posted by MI-XC View Post
    Good to here you found a solution. Iím having the same slippage issue and will try this solution. How long and wide did you make the shim?
    .
    I found this Leonard Zinn article and tried to follow his instructions. Roughly 1Ē x3Ē perhaps a little smaller.

    https://www.velonews.com/2002/12/bik...your-bike_3288

  40. #40
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    Quote Originally Posted by Fattyrider38 View Post
    I also ended up going with a small red bull can shin and I havenít had any more issues it barely fit in there but seems the fix the creaking and slipping problem.
    I think the red bull shims are only compatible with DH bikes

    That Leonard Zinn article is confidence inspiring enough that I am headed to the fridge to get some shim material as I type.....my seat most only slips a few mm every other ride but carbon past makes it creaky and I hate constantly messing with it

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