Specialized Crux seatpost size

[shankldu]

Hello my brother, and idea what size seatpost this takes , I'm half blind w a sae tape looks like a like a little under 1 1/16 across the seat tube . 2012 model . Any help is much apriciated .

[KonaSS]

27.2

I believe every Crux that has ever been sold has been this.

[shankldu]

based on the coversion 1 1/ 16 comes out to roughly 26.8 but want to be sure

[shankldu]

and I have tried a 27.2 that I had laying around.

[rowebr]

and I have tried a 27.2 that I had laying around.

Yes the Crux should take a 27.2 seatpost.

But the 27.2 post that you tried did not fit?

You could try measuring the seat tube opening front-to-back, then side-to-side, see if the measurements are noticeably different. Best to do that with a caliper. Perhaps the top of the seat tube is ovalized from a previous owner overtightening the clamp on a post that was too small.

[shankldu]

correct 27.2 does not fit I ordered a 26.8 well see what happens

[wildboar]

I have a 2012 crux, yellow & blue, rim brakes & its post is 27.2mm.

[jtbadge]

Try a different 27.2 post, the one you are trying might be out of spec. I've had Nitto and other brand posts measure too large, and a Thomson come in under sized.

If that doesn't fit, the seat tube has been pinched or otherwise misshapen from using an incorrect seatpost size. A 26.8 post will be too small and slip, causing over tightening of the seatpost clamp like we are likely seeing here.