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Old 01-19-10, 07:02 PM   #1
lemniaalsa
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Help with seatpost sizing rod

Hello all

I went to my local bike shop to measure my seat post size and I measured it to be where it's indicated in the picture. The owner didn't know if it was corresponding to the line above or below the measurement. So, in the attached picture, is my seat post a 25.8 or a 26?

Thanks a bunchh
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Old 01-19-10, 07:19 PM   #2
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time for the calipers
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Old 01-19-10, 07:25 PM   #3
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Hmm? I just need to know if the numbers correspond to the line above or below.
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Old 01-19-10, 07:29 PM   #4
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Never seen or used one of those but I would guess that the number corresponds to the section next to the number.
An inexpensive caliper would confirm.
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Old 01-19-10, 07:31 PM   #5
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Never seen or used one of those but I would guess that the number corresponds to the section next to the number.
An inexpensive caliper would confirm.
But the numbers are right in the middle haha.
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Old 01-19-10, 07:50 PM   #6
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Take it to a shop that has both seatpost sizes and see which one fits. Then you can tell the owner of the tool how to use it properly.

-j
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Old 01-19-10, 07:56 PM   #7
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Well I would say the 25.8. The seat post sizing rods are not conical, they are stepped. So if it did not drop all the way up to the top of the 26.0 it was the one below it. However it is pretty common for the top of the seat tube to be deformed from being tightened too much and you might not want to assume it's the 25.8. Both are pretty uncommon sizes, what brand of frame is it?
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Old 01-19-10, 08:18 PM   #8
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most definitely 25.8, the lines refer to the number below.
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Old 01-19-10, 10:16 PM   #9
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Well I would say the 25.8. The seat post sizing rods are not conical, they are stepped. So if it did not drop all the way up to the top of the 26.0 it was the one below it. However it is pretty common for the top of the seat tube to be deformed from being tightened too much and you might not want to assume it's the 25.8. Both are pretty uncommon sizes, what brand of frame is it?
It's a nishiki custom 12
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Old 01-19-10, 10:19 PM   #10
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my vote is 25.8. Start at the bottom, the only marking is above it, so if you go up, pairing the number with the mark, it must be 25.8.

Did that make sense to anyone else?
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Old 01-20-10, 12:08 AM   #11
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Originally Posted by lemniaalsa View Post
Hello all

I went to my local bike shop to measure my seat post size and I measured it to be where it's indicated in the picture. The owner didn't know if it was corresponding to the line above or below the measurement. So, in the attached picture, is my seat post a 25.8 or a 26?

Thanks a bunchh
The biggest number that fits into your seatpost is the seat tube size, and thus the seatpost size. It is a very handy tool for quickly ascertaining seatpost size - we have both size ranges of those rods at our shop. Using a caliper is not accurate enough because the top of the seattube is usually deformed to give an unreliable size.
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