I ride a 53 kilo and have about inch or more space from the TT to the family jewels. With the stock cranks (165mm) I had a good 6-7 or so inches of seatpost exposed from the clamp. Ever since I switched to newer cranks with 175mm crank arm length I had to compensate with lowering my seatpost and now only show about a fist full.

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wow i didnt even read the 2nd page or previous post dates before I quickreplied *facepalm*