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Discussion Starter · #1 ·
It's a 2010 Speciallized Allez Sport. I'm just under 6' and riding a 56cm. I don't believe the frame is too small (i've ridden down to a 52cm comfortably, though not a compact frame), but I'm getting worried about the seat post. I took it out for some reason and noticed that there are only about 3-4" of seatpost left in the seat tube.

It hasn't broken yet, so the seat post is strong enough (it's aluminum and cheap). But, I'm starting to wonder if there's a chance of damaging my frame. It's not like the frame can be butted there if the seatpost slides cleanly (it also just isn't…as far as I can see).

The 'solution' is obviously to buy a longer seat post, but…do I actually have to spend that money? Any way to tell if it's worth caring about?

Yeah…so…compact frames…how do they work?
 

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They're (compact frames) meant to take a longer seatpost setting at least.

I don't know of anyone's that had an issue with overly-extended seatposts. My trainer bike had to run on a short seatpost with the min. mark well-exposed. I got away with that most likely because of my weight, and the fact it was on the trainer to never face bumps, etc.

If you need the mental reassurance, get a ~410mm post.
 

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As long as your post extends at least an inch, preferably 2 inches, past the seat tube/top tube junction, you'll be fine. As a side note, I've always felt it wise to avoid super-light seatposts with compact frames, the extra length needed just gives a longer fulcrum and more chance for them to snap.
 

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huvia ja hyötyä
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Seat posts have a line marked for minimum insertion. Usually close to 4" from the end. And yeah, the post needs to go below the top tube junction. Being a bit heavy myself, I prefer to have "enough" post in the frame.

Those who really care about grams can have the short posts.
 

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Larry Lackapants
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indication on frame

There's a small note on my L giant (approx size 58) that says something about having the seat post inserted 10 cm in the frame measured from seat tube edge. 4 inches should be around that value.

Frame integrity depends a lot on the size of the post that is above the frame and also on your weight, but if the post is not insanely long, the frame should be safe.

btw: the min insertion mark on the post guarantees seat post integrity while the min insertion depth marked on the frame or specified by the frame manufacturer guarantees frame integrity.
If you know both , respect the most restrictive one..

good luck
brblue
 

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Discussion Starter · #6 ·
@blue, where would I find the min. insertion for my frame? I'm not sure it came with a book or anything, and I don't see anything on the Spec. website.

Thanks…I guess I'll just wait and see what happens…and buy a longer one if I ever buy a new one.
 

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Rub it............
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Just make sure that the seat post extends below the top tube/seat post junction. As long as your seat post does this, then the warranty on the frame stays intact if a weld decides to give way. And Specialized will ask the shop doing the warranty frame swap how much seat post was inserted.
 

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Larry Lackapants
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As the other posters said, just don't override the min insertion limit for the seatpost and you will be ok.
Was just saying what I'd do in case both the seatpost and the frame manufacturer specify some min insertion limit...
 
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