Creaking Seatpost - Out of Round?

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SgtRock
Posts: 63
Joined: Sat Mar 14, 2015 9:22 pm

by SgtRock

Just taken delivery of a new titanium frame which I built up at the weekend. First ride out on Sunday I was getting lots of creaking / pinging from seat / seat post when shifting my weight or going over bumpy road surfaces. At the time I wasn't sure if it was the clamp on the rails or the post itself. At the end of the ride I tried moving the seat post forward and back (Not using the seat) which isolated the problem as being the post in the seat tube.

I removed the post and added more carbon paste and retorqued to 6Nm (max allowable - it had been installed at 5Nm before) and it seemed to cure things - at least with my manual push pull test in the garage. I also added copperslip to the clamp area. Riding next day it was better but the creak was still there and seemed to get marginally worse during the ride. The seat clamp I was using is reasonably svelte (10mm depth) so I tried the one supplied with the frame which is 14mm deep and reinstalled. Only had a quick test over the biggest lumps I could find, which living where I do is not difficult, and I could still induce the ping!

I spoke to the frame builder who suggested, as you might expect, that the seatpost might be out of round - so I went and got myself some Vernier callipers and the results are, measured just above the clamp: Front to back 31.46mm and left to right 31.78mm i.e. it is out of round by approximately 0.3mm. This would figure with the front to back movement I can induce by grabbing the seatpost. I measured the stock post supplied with the frame, but not used, and this was only around 0.08mm out of round. I don't want to use this post as it is a 3K weave and wont match with my other kit and this post is destined for Ebay so I don't want to mark it.

So I think the post tolerance is the problem, which in this case is a Cinelli Neos post that is constructed as an aluminium tube with a unidirectional carbon outer (I previously had a 27.2mm version of this post on a stainless steel frame with no issues). I think I am going to try a different, full carbon, post and if this works the Cinelli will be sent back for a refund but before I do spend more money has anyone ever experienced a similar problem?

I would be very grateful for any advise or tips. Thanks in advance.

by Weenie


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xena
Banned
Posts: 1149
Joined: Tue Apr 15, 2014 9:49 pm

by xena

If you put some clear coat on the post you want to use and build the clear coat up slowly so you post go's into the frame quite tight [ wiggle it] you will have no issues with creaking and you will find you don't have to clamp your seat post collar down tight either.
You only need to put the clear on the contact point and it will not be visible .
problem solved :thumbup:
Xena a demi god among the digital demimonde that is WW community

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SgtRock
Posts: 63
Joined: Sat Mar 14, 2015 9:22 pm

by SgtRock

Clear coat - is that the same as lacquer?

Tenlegs
Posts: 289
Joined: Wed Jul 16, 2008 10:37 am

by Tenlegs

I'd send it back for a refund 0.32mm out of round is far too much, Deda superzero I have is 0.03-0.05 max.

xena
Banned
Posts: 1149
Joined: Tue Apr 15, 2014 9:49 pm

by xena

SgtRock wrote:Clear coat - is that the same as lacquer?


Yeah. What you use to protect your paint work.
There are a lot of choices you could even use clear nail polish. Just build it up around the contact point ,you wont need much just a layer or 2 and that will sort you out. Just make sure its dry and kind of ramp the layer so there is less of a obvious edge so when you wiggle you seat post in you don't scrape off the clear. I use it on my Weight weenie trek so I don't have to clamp down the seat post collar tight. Works perfect. :thumbup:
Xena a demi god among the digital demimonde that is WW community

http://i.imgur.com/hL5v3ai.jpg

https://www.flickr.com/photos/131970499@N02/

SgtRock
Posts: 63
Joined: Sat Mar 14, 2015 9:22 pm

by SgtRock

Creaking resolved. Cinelli post returned and refunded and a Zipp SL Speed 2012 post is now fitted and seems to have addressed the problem.

Thanks for the help.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
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