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saddle sliding backwards

Old 09-21-23, 03:21 PM
  #1  
Aero-X
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saddle sliding backwards

Guys,

I noticed my Specialized Toupe Ti rail saddle tends to slide back. I previously roughened the Ti rail with sand paper and as well as the clamp surface to increase friction. The seat post is a Canyon carbon. I previously torqued to 9NM max. I put a piece of red tape on the rail to spot the correct position. Now the red tape got pushed to the front which means the saddle slipped backward about 5mm. Is there anyway I can make the saddle stop sliding backward? I did notice the riding position changed and the lower back felt sore during the last ride.

Thanks

AX





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Old 09-21-23, 04:17 PM
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FBinNY 
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There's absolutely no way a properly clamped post could slide.

Not calling you an idiot or liar, just saying the clamp is not properly tightened.

Odds are the clamp is bottoming out on something else rather than the rails.

Check the center to see if it's touching. If you can't spot the issue, note the gap on the outside, remove the saddle, then confirm that you can close the clamp past that.

While it's apart thread the nit onto the bolt and not how far beyond the top the bolt extends. It needs to be more than what you see now.

Also, if you're using a torque wrench and tightening to a spec. try the b old fashioned way of tightening until it holds. (after confirming that nothing is preventing that)

Last edited by FBinNY; 09-21-23 at 04:27 PM.
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Old 09-21-23, 05:23 PM
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maddog34
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Want to see if some part is bottoming out on another part? Place Play doe in between the suspects and clamp normally... then remove the parts and see if the doe has squished away completely.. i've also used plain old white bread to do this test... we used this technique to look at Squish Band height or Valve head/piston interference in high performance Engine combustion chambers, etc... simple, and it works.

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Old 09-21-23, 05:25 PM
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Crankycrank
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I have never setup a Canyon seat post but I have had several different two bolt posts that are a real PITA to setup needing to fiddle around with getting the right setback and angle while keeping the clamp in the right orientation. Just guessing but the top of your clamp might need to be more equally centered over the bottom half of the clamp. Yours has the top slightly rearward and may not allow the full clamping force from both bolts. Just a guess though.
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Old 09-21-23, 05:26 PM
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Grease the bolts. Your 9nM might be getting used up with friction rather than tension.

But I agree that this could be a seatpost designed for oval saddle rails and bottoms out with round rails.

What does Canyon say?
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