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Sleeved titanium seat tube slippage w/ seatpost

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Sleeved titanium seat tube slippage w/ seatpost

Old 09-24-18, 02:31 PM
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masi61
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Sleeved titanium seat tube slippage w/ seatpost

So I have a used “Veritas” titanium road bike that originally had a 30.0 seatpost. The previous owner said that the seatpost had become frozen in the frame but the LBS was able the retrieve it. Apparently the seat tube bore was a little ragged after that so they chose to use a 30.0/27.2 shim to permit the use of the more standard 27.2 size post and have fewer worries about the internal titanium seat tube bore.

I painted on a healthy amount of Permatex copper anti seize compound between the shim and the frame. Then, I used Finish Line grip paste on the Ritchey Superlogic seat post that I’m using. The seat collar is a Hope brand aluminum 34.9 one. I was having a lot of creaking so I tightened the collar until the creaking stopped. Unfortunately even though I got the creaking to stop, the saddle itself has been rotating slightly to the right on my rides and I will notice the mis-alignment when I get home. So I tightened the Hope seat collar bolt even tighter to try to stop the sideways rotation and I snapped the aluminum bolt. I bought a replacement bolt (8mm fine thread x20mm BTW). And used a torque wrench and currently have it up to about 9.5 Nm and after my ride the other day it did the exact same thing - rotated to the right slightly. On no occasion has the post dropped down at all. This makes me think that the grip paste is holding but something is going on in the frame bore between the ti tube and the aluminum shim.

I could remove some of the copper antiseize - that was one of my ideas. Another idea is to place a strip of shim stock in the frame between the tube and the 27.2 sizing shim.

So far I am sticking with the Hope collar and was Hoping (pardon the pun) to make it work. I thought of more options such as stronger, double bolt seat collars which I can deploy if needed.

Just wondering if any of our BF in-house mechanics have encountered this type of sideways seatpost slippage where the post doesn’t actually drop down. How did you deal with it?


Last edited by masi61; 09-24-18 at 03:07 PM.
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Old 09-24-18, 02:46 PM
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Well I was checking eBay and see where they make a 30.1/27.2 seatpost reducer shim for under $3 (from HongKong). I went ahead and ordered one - it might just be that little bit more snug to ameliorate the sideways post rotation issue.
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Old 09-24-18, 02:57 PM
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I have 3 bikes that use a seatpost sizing shim
1 aluminum frame oversize, with a Thudbuster ST in it
another, steel bike friday, with a Thudbuster LT...

3rd, another Bike Friday, the Tikit*, came shimmed to 27.2,
I added a 27.2 to 25.0 shim to use the Campag post, I originally, had on my AlAn..
[I had that sleeve to use before I got another post on my steel CX bike,]
*Kalloy Uno had angle slip issues, when I hit a bump no bigger than a sidewalk curb cut ,
I gave it away..

So, a shim sleeve USE, UK, within another QBP/'Problem Solver',
or Wheels of Boulder..... it works OK..






....

Last edited by fietsbob; 09-24-18 at 03:00 PM.
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