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How do I make a seatpost opening larger?

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How do I make a seatpost opening larger?

Old 03-01-24, 12:46 PM
  #26  
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A slight hijack of this thread.

Thank you to cyccommute.

For anyone seeking a seat tube gauge, the one he posted is on the Wheelsmith site for $19.92 with free shipping. Last fall I balked at a set of Stein gauges that were on for private sale $40 and still kick myself.
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Old 03-01-24, 12:49 PM
  #27  
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Originally Posted by J_Climacus
Hi all, thanks for the responses so far......
Why are you making something so simple into a complicated problem.

Unless you have reason to believe someone put thr frame in a vise and pressed the lug into an oval, it's a simple process to restore the area to the original condition.

If, as I suspect, and you can easily confirm, the slot is pinched closed a bit, the answer is to spread it back open.

Unless you're using a thin CF post, the lug will flex and conform to the post when clamped, so no need to get it round.

Obviously, you need to know the right size post, either based on the decal, measuring 2 axis and averaging once the slot is spread to match top to bottom, or using an inside caliper to measure the tube below the lug.

As for spreading the slot, nothing special needed, shy of care and patience. If you own a large screwdriver, you can tap it in, working from the top inside downward and alternating a prying/levering action with tapping it deeper. Stop when the top of the slot matches the bottom then check the dimensions.

Seriously, this is a 2 minute job. if you're not comfortable doing it, bring it to someone who is.
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Old 03-01-24, 12:58 PM
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Originally Posted by SurferRosa
Do you mean "seat tube"? ...What??
Ha... Ya got it Surfer. The Seat Tube... Yep... Thanks
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Old 03-01-24, 01:04 PM
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Originally Posted by FBinNY
If you can easily confirm the slot is pinched, the answer is to spread it back open.
But it looks quite uniform and perfect.



Use what works!
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Old 03-01-24, 02:21 PM
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Originally Posted by SurferRosa
But it looks quite uniform and perfect.



Use what works!
It's entirely possible that the only problem is the OP assuming the post he has is wrong.

That's easy enough to confirm by seeing how much the slot closes when the post is tightened. Normal is less than 1mm.

If, the post size is confirmed, and won't fit, the lug can be spread by putting a pipe in a vise, fitting the frame over it to less than lug depth, and gently levering it back and forth.

But, if you scroll back, this will be the third time I mention confirming the post size and the true nature of the problem before "fixing" it.
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Old 03-01-24, 03:59 PM
  #31  
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Originally Posted by FBinNY
But, if you scroll back, this will be the third time I mention confirming the post size and the true nature of the problem before "fixing" it.
The post is the right size.

Thanks for the advice, all -- I used the reverse-thread-with-a-penny trick and it worked. I did not re-stretch the opening past what I needed to get the 27.2 post in, so I assume it will still be too small once I take this post out. But it will work for now, and I don't intend to change saddle height often/ever on my stationary bike.
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Old 03-01-24, 05:12 PM
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Originally Posted by J_Climacus
..... I assume it will still be too small once I take this post out. But it will work for now, and I don't intend to change saddle height often/ever on my stationary bike.
If you change your mind, your very safe to "stretch" it slightly more so it naturally springs back to the right size to slide the post in easily.
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