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I recently acquired up a secondhand Kinesis Pro6 and swapped the seat post for a carbon one I already had. The carbon post slips on every ride, especially on rougher surfaces, I've tried Tacx carbon assembly paste but that did not help. After the last ride, I noticed that the surface of the post was coming away in strips! I think it's the lacquer but can't be 100% sure.
[url= https://farm2.staticflickr.com/1733/27556474407_e69da8ac04_k.jp g" target="_blank">https://farm2.staticflickr.com/1733/27556474407_e69da8ac04_k.jp g"/> [/img][/url][url= https://flic.kr/p/HZ58MH ]2018-05-29_08-49-50[/url] by [url= https://www.flickr.com/photos/rjohnson76/ ]Rob Johnson[/url], on Flickr
Is the post still safe to use (the damage is above the seat tube level)?
Are all assembly pastes (the Tacx one is the consistency of gel but doesn't have much grit in it)? Is it worth buying a double bolt seatpost clamp instead?
Cheers
Looks like top carbon layer is damaged to me. Don't know about safety. If weakened enough it could snap at the clamp I guess. More a case that this damage will get worse if it keeps slipping.
Is there a manufacturer spec of paste for the post? Not sure what I've got as lost the label, but it's purple stuff that's a little bit gritty, and seems to do the job (of reducing torque required and eliminating bonding issues with carbon + alloy mix, where relevant).
How tight are you going on the clamp? Carbon frames and posts can take more than you might think. Again, any manufacturer specs on torques? They should be based on using carbon paste though.
Other thing is to check the frame tube for potential damage. Though wouldn't explain slipping but might explain the damage to the post as it slips. I wouldn't expect a slipping post to do much than just slip.
And, obvious I'm sure, but check the post size, or do you have a shim? Wondering if something is a fraction too big/small. Though again I'd not expect the damage on slipping.
Personally I'd not be using that and going back to the original post/
I'd also be measuring the diameter of the original post and comparing it to the carbon post. I suspect the carbon post will be undersize.
Are you using a QR seatclamp? Perhaps a different one might help?
It's the original Kenisis bolt up clamp. The carbon post had worked fine on my (also Kinesis) road bike.
FWIW I found the seattube sizing on my pro6 a little on the slack size so used some grip paste to keep things snug and it's been ok
That's with an alloy post though and your post looks a bit knackered. Is it possible it's been moving inside the tube a bit, causing the damage you've shown?
Yes I'm sure the damage was caused when the post slipped down as its all above the position the clamp is at before the post slips. I've ordered 2 bolt clamp to replace the current one which I found had a damaged barrel nut. I guess I better junk the carbon post too, don't want to risk a nasty impalement!
Yes I'd not trust that to be honest. My pro6 has been great but the finishing was a little poor in places. Work taking a file and some fine emery paper to the seat tube slot and collar to take off any sharp edges.
The paste I use is finish line, it's got a gritty feel and seems to do a good job.