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Discussion Starter · #1 · (Edited)
2016 specialized rumor in size small and no one locally can seem to help other then we cant find a dropper post that will work. So hopefully someone here can make a suggestion. The frame is funky and the insert lenght can no go longer then 5.25 inches from the fram up she rides at 5.5ish inches. What dropper post do I need? I know its a 30.9 post size other then that im at a loss.

Thanks in advanced
 

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Your post is a bit confusing. Are you saying the frame can fit 5.25" and there's about 0.25" of seat post sticking out, so a total of ~5.5"? In that case, she would need a 125mm dropper.
 

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I just had to source a small dropper for an older frame. I had 95mm insertion length, and the seat tube is interrupted below by a shock. Here's the table I created. I got the KS ETEN external 325 length, 75mm drop, 100mm insertion. These are all 30.9s except for the 27.2 (which could be shimmed)
1939734
 

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Discussion Starter · #6 · (Edited)
Your post is a bit confusing. Are you saying the frame can fit 5.25" and there's about 0.25" of seat post sticking out, so a total of ~5.5"? In that case, she would need a 125mm dropper.
Yes the seat post can fix a max of 5.25 into the frame. She tides a other 5.5inch a I've that
 

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yes the frame can fit 5.25 but she's using another

Yes the seat post can fix a max of 5.25 into the frame. She tides a other 5.5inch a I've that
What?

First of all, read about the important dimensions of dropper posts. That PNW article covers them. Now use the terms described in the article, and state your measurements in metric terms (that's how dropper posts are measured).
 

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Discussion Starter · #8 ·
What?

First of all, read about the important dimensions of dropper posts. That PNW article covers them. Now use the terms described in the article, and state your measurements in metric terms (that's how dropper posts are measured).
Read above
 

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Discussion Starter · #9 ·
I just had to source a small dropper for an older frame. I had 95mm insertion length, and the seat tube is interrupted below by a shock. Here's the table I created. I got the KS ETEN external 325 length, 75mm drop, 100mm insertion. These are all 30.9s except for the 27.2 (which could be shimmed)
View attachment 1939734
I was looking at the eten as well. Just seemed a bit long for what I was needing ?
 

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Discussion Starter · #11 ·
I read it. can't figure out what you're trying to say. Use the industry accepted language to describe the measurements you've taken.
Sorry your having trouble. I am not going to rewrite the original question. Everyone else seems to be doing ok. Thanks for you help take care.
 

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Everyone else seems to be doing ok.
doesn't read that way to me.

you have to measure absolutely everything when choosing a dropper post. measure in metric. it's a helluva lot easier than converting every measurement you take so you can compare to various droppers on the market (which all have dimensions stated in metric).
 

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Discussion Starter · #14 ·
doesn't read that way to me.

you have to measure absolutely everything when choosing a dropper post. measure in metric. it's a helluva lot easier than converting every measurement you take so you can compare to various droppers on the market (which all have dimensions stated in metric).
Have a good day thanks for your time
 

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Yes the seat post can fix a max of 5.25 into the frame. She tides a other 5.5inch a I've that
Do I understand it right in the way that she can insert the post maximal 5.5” and the post is sticking out another 5.5”?
 

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I should clarify that 'insertion' on the table is the minimum insertion for that post. 5.5" (140mmish) insertion should allow fitting of most droppers. The part that will stick up beyond the seat collar is the length - drop - insertion value. So a 325 with 75 drop is 250mm long at it's compressed setting. If 140mm is in the seat tube, that leaves 110mm above the seat collar (roughly 4.25 inches). Uncompressed it will be 185mm (7 1/2") above the seat collar.

Measure the current seat height above the seat collar. Then you can write some formulas to see how much 'effective drop' you get with various posts (their min length is calculated and the seat height needs to be at or below the uncompressed/max length.)
 

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Where are you measuring to on the seat post/saddle? The accepted reference point is the seat rails, so is that 5.5" (140mm) from the top edge of the seat clamp to the saddle rail?

You also don't mention if the frame has cable routing for an internal dropper or not? If you need an externally routed dropper this will eat into what you have to play with.
 
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