Wondering if anyone else has experienced this issue. So I bought a steel frame hard tail recently. The dropper post collar has been slipping into the seat tube slowly from use. As we know overclamping will inhibit the post from extending to the fullest travel. I’ve even tried a collar with a larger bolt, and it still slips down. Slower, but still slips. I’ve tried cleaning the collar/carbon greased… STILL slippling.
What am I missing here? Is this the dropper post issue itself? Should I try a completely different dropper post? The post itself works fine albeit a bit short for my legs, but doable for now.
Any suggestions from techs or anyone that has had a similar issue please help! I can’t afford to buy a new dropper right now either lol

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Friction paste.


Ive tried that stuff, still didnt work.

Measure the frame and post with vernier calipers, to see if one of them is out of spec (ideally measure bellow the seat tube slot).
I believe you typically want the post to be 0.1-0.2mm smaller than the seat tube.

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Yeah, im thinking its coming down to the post itself not being suitable for the frame. It works yes but it obviously isnt spec’d properly for the frame and in result keeps slipping. Ill do this and take action. Thanks

I’d guess the tolerances are out a little too much on each in the wrong direction.
If it is just the frame or just the dropper that has tolerances way off, hopefully the manufacturer can help get you sorted.
There are also dual bolt collars like Engin Dual Bolt Seat Collar (33.1/34.9/36.4/38.6mm) — Engin Cycles to spread the load, but that would be a last ditch effort IMO.


have you tried the classic pop can shim yet?


I haven’t LOL This is a thing? I like where your head’s at. DM me what you’ve done or are thinking to make that work. :thinking:

It’s not pretty; but I’ve cut out pieces of a pop can to use as a shim in the past. I don’t think I’d resort to that on a good bike, though. :stuck_out_tongue_winking_eye:


Problem Solvers also makes a bunch of shims starting at 0.7mm thick.

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This is probably exactly whats needed. Thanks dude.

I have been riding a steel hardtail for years with a 26.8 seatpost in a 27.2 seat tube shimmed with popcan.


So the theory works, good to know. Thanks

Any heavy duty mechanic, or millwright would have shim stock laying around. It’s used extensively in alignment of rotating equipment and machinery. Its usually gold or bronze colors and comes in boxes with multiple thicknesses.

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Seems like this is the answer. I appreciate all the feedback from everyone.

Try orientating the collar 180 degrees and re torque.