the p2k has a metal ‘stay’ that goes around the post before it enters the frame. this prevents the post from going down into the frame.
question: can i take this piece out so i can get my saddle lower or do i have to have the post cut down? I have a regular post (not carbon).
The shim must stay in place - cutting the post is what you need to do - or order a shorter one from Cervelo
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Maybe I’m missing something here, but something doesn’t sound right.
First, the seatpost shim goes down inside the seat tube, so it shouldn’t have any effect on how low you can get your saddle.
Second, I’m no fit expert, but if you need to get your saddle that low you’ve probably got a frame that’s way too big for you.
Something really isn’t right here. Exactly how long is your post? What size frame? I have a Dual and recently changed from the aluminum to the carbon post (both fit the P2k). With either post, I can get them pretty flush with the seat clamp (58 frame, longest post available) without removing the shim. If you do have a frame that is very small they (lbs orother source) may have given you a post that is too long for it. Before cutting that thing. Carefully pull out the shim (so it doesn’t fall in and you have to shake the frame upside down to get it out), take a look at it and see if there is enough grease on it. Makes a difference. And just an FYI, all that extra seat post adds a little weight.
for clarification. it’s not the shim that’s stopping the post. i think it’s stopping where the frame heads back toward the wheel. just below the shim
i have a 55 frame. the post is 9.5 inches long, but only drops 4 inches before it stops. does this sound right?
thanks,dave.
No that doesn’t sound right. I have the 11.5" and I can insert it all they (no pun intended) :-). A 4 inch drop sounds like something may be in there blocking it because your seat tube should be longer than 9.5 in. The bolts that afix your bottle cage. If the top bolt is 4 inces from the seat clamp (probably not) then that may be what’s causing the 4 inch in. If it’s not going in easily don’t force it or you may be faced with more problems than a long seatpost. 
Something doesn’t sound right. Before you go cutting down your seatpost, go back to the shop where you bought your P2K. I had to cut my carbon post on my P3 but that’s because of the aero rear wheel cut-out that eliminates much of the seat tube. Looking at the pics of the P2K, the rear wheel cut-out is quite a ways down on the seat tube so it shouldn’t factor into your problem. Good luck. Let us know what the problem was.
okay, i took a flashlight to it. the problem is some material on the inside of the tube where the rear wheel supports meet the frame. i assume this is uncommon. maybe it could be shaved down?
Somtimes little burs like that happen when fabricating metal. A slight defect that would normally go un-noticed. Sounds like it just needs to be smoothed out a little. Depending on how large of a bur it is you could probably gently sand it down (I have no idea what weight you would use) but I would take it back to the LBS and let them handle it. Good luck!
Don’t touch it, what people are suggesting you do its to turn a good weld into a bad weld. You need 2 1/2 inches of seatpost in the frame, the rest is ballast. So figure out the seat height you need, cut the seatpost so 3 or 3 1/2 inches are inside to leave yourself some wiggle room, and off you go. It is really not that much different on a P3 or a P2K, it is a bit different on a Dual because the seatstays go up higher.
I can relate to this. I had a hell of a time getting my seat post down to where it belonged. Check the end of the post and the inside of the frame for burrs. I filed off a little burr on the post but it was still damn tight. I greased it up good and a few taps with a rubber hammer got it to wear I wanted.
Most people I talked to didn’t have this problem but a few other Cervelo owners found the seat post to be very tight.
can anywhere cut it if they are careful? my lbs is closed today…home depot?
All you need is a hack saw. But rush into it too quick. Wait the extra day and confer with the LBS.