Strange I have had this problem before, but it was the clamp being slightly loose. the reason why you can't find the issue when you pull over is because the clamps are still "tight" enough not to show any movement when you press on it. But once you sit on it, the weight of your full body can create some movement. I would reccomend removing the saddle, cleaning the saddle and clamps of any grit that may have snuck in there and fully tightening the clamps once more. If that doesn't work you could have damaged the clamps/bolts if you hit a pothole hard. Because of the test you said you did, it doesn't seem like it could be anything other than your seat/seatpost.

 

Lube?

If you are sure it is your post, mark its position, remove, clean both post and inside the frame, lube with antisieze and re insert. You can use grease too i suppose but you just have to do this exercise periodically to keep the post/seatube from cold fusing. And do this BEFORE you go any further, test for the squeak and if you still have it then you need to move onto the seat rails.

 

If you are sure it is your post, mark its position, remove, clean both post and inside the frame, lube with antisieze and re insert. You can use grease too i suppose but you just have to do this exercise periodically to keep the post/seatube from cold fusing. And do this BEFORE you go any further, test for the squeak and if you still have it then you need to move onto the seat rails.

This is good advice. You can use some spray lube on the rails/clamp section. Worked for me. A previous squeak on my Merckx was on the post/seat tube intersection. Lubing with grease fixed the problem for a few months. Started squeaking again, so I just redistributed (mid ride) the lube that was already on the post. Prior to that, I had torn down almost the whole bike: Stem, headset, cranks, pedals, the works. I couldn't get the BB out because I didn't have a Phil Wood BB tool. Luckily it wasn't the BB.
The last similar squeak that popped up on my most recent bike, was a bad BB. Replacing it fixed the problem.
The problem is, there are so many places a squeak can come from, and identifying it can be very tricky.

 

Combining recommendations

The problem is, there are so many places a squeak can come from, and identifying it can be very tricky.

As a general guideline, all metal to metal contact surfaces should be greased or otherwise lubed. This means the seat post, the seat post clamp and bolt, all the parts within the seat post head, and the saddle rails. Also, saddles often squeak where the rails enter the saddle, so oil dribbled into each of those contact points will sometimes solve the problem when other things don't work.

 

Grease is Good!
However, a little spritz of the 'W' word can work wonders for squeaks.:thumbsup:

 

Thanks everyone. I was thinking it might be the area where the rails enter the saddle shell. I'll check the post first and re-apply anti-seize. If that doesn't do it, I'll start looking more closely at the rails in the clamp and where they enter the shell.

 

Persistance

I'll start looking more closely at the rails in the clamp and where they enter the shell.

Just be aware that it may take a bit of time for the oil to work its way into the "squeak point" of the saddle rails. I had a click problem on a new Selle Italia SLR, and oiled the rails where they entered the shells by hanging the bike on the wall so that the oil would run down into the saddle (hung the bike both ways on separate days, letting the oil soak). This solved the probelm for a few weeks, but then it came back. I repeated the process (maybe twice; it was a while ago) and that finally nailed down the noise.

 

I went down this long and frustrating road last season and finally got resolution. Twas a creak/tick I isolated to the post/saddle. (A noisy bike really detracts from a ride). Here goes.

Starting point:
Ti compact frame (much exposed seatpost), Salsa Shaft post, Campy collar, WTB Shadow Stealth saddle (Ti rails).

Standard assembly: clean contact surfaces, generously greased post, lightly greased rails, lightly greased collar - creak
Disassemble, repeat - creak
Disassemble Salsa Shaft head (neat design, BTW), clean and lightly grease, reassemble all (anecdotes on MTBR regarding this post and noise) - creak
Replaced collar with Salsa Lip Lock - creak
Replaced post with Reynolds carbon - creak (and now I’m pissed and despondent)
Lightly filed/emoried all inside edges of the frame’s seat tube which contact the post (top inside edge, cutout, seatstay penetrations), cleaned, grease again - Hallelujah, no creak.

Good luck and let us know what you find.

 

My personal creaking nightmare

The bike is an Airborne Manhatten Project ti/cf stay semi compact frame mix of DA/105 parts had an FSA crank/bb at the time too, Mike Garcia built DT Swiss/Speedcific wheels.

The noise started in the spring riding season, an intermitten tick. No rhyme or reason to the noise. I searched................for 2.5 years to isolate. It would come and go as it pleased and had gotten to the point that I chose to ride one of my other bikes than ride the super bike because of the tick. I replaced the bars/stem/post/bb/crank/tried various saddles/cassette/chain. Disassembled, cleaned and lubed about 3 times. Still ticking when I was JRA softpedaling, nothing heavy. I finally decided to send the rear wheel back to Garcia for inspection as I felt I had nothing to lose by having it overhauled or inspected. It turns out that the freehub internals were shot after 3000 miles or so due to riding in extremely wet weather for 4 days in a row (I suspect)(, hurricane remnant the previous fall before the noise began) I thought sealed bearings meant that these types of conditions would really not effect sealed bearings. I still get an occasional ping/tick with the bike and suspect the saddle rails, but I may be replacing the saddle with something else if I sell my (SHAMELESS PLUG) SI Signa that is in the RBR ads!

 

I went down this long and frustrating road last season and finally got resolution. Twas a creak/tick I isolated to the post/saddle. (A noisy bike really detracts from a ride). Here goes.

Starting point:
Ti compact frame (much exposed seatpost), Salsa Shaft post, Campy collar, WTB Shadow Stealth saddle (Ti rails).

Standard assembly: clean contact surfaces, generously greased post, lightly greased rails, lightly greased collar - creak
Disassemble, repeat - creak
Disassemble Salsa Shaft head (neat design, BTW), clean and lightly grease, reassemble all (anecdotes on MTBR regarding this post and noise) - creak
Replaced collar with Salsa Lip Lock - creak
Replaced post with Reynolds carbon - creak (and now I’m pissed and despondent)
Lightly filed/emoried all inside edges of the frame’s seat tube which contact the post (top inside edge, cutout, seatstay penetrations), cleaned, grease again - Hallelujah, no creak.

Good luck and let us know what you find.

Oh boy. Thanks. I hope I don't need to go to such lengths.

 

I had a similar deal...

Thanks everyone. I was thinking it might be the area where the rails enter the saddle shell. I'll check the post first and re-apply anti-seize. If that doesn't do it, I'll start looking more closely at the rails in the clamp and where they enter the shell.

...with a Douglas Race Evo saddle on one of the two Titus Oseos I got from Colorado Cyclist last year. Great bike, crummy saddle, because I didn't realize that the rails were in the process of detaching from the saddle...which finally happened in the middle of a sponsored ride. Fortunately, one of the ride workers had some duct tape, otherwise I'd have had a ten mile standing ride back to the start/finish...

 

When I've had squeaky seats I've been able to produce noise by grabbing the nose of the saddle in one hand, the back of the saddle in the other, and alternately pushing one down while pulling the other up.