Creaking seatpost advice - options

Binaural

Eats Squid
I've just bought a brand new seatpost for my roadie. Now, I am heavy (110kg) and ride a lot so I represent a limit load case for these sorts of parts. It passed the carpark test with everything knotted up to spec with a torque wrench, so I was surprised to hear it creaking like a galleon under full sail up the hills. Given I thought I had done everything right I would like to ask the hive mnd:

1. I put fibre grip paste on the seatpost (titanium frame) and then refitted the seatpost collar with anti-seize paste. The tightening bolts are loctited. I didn't grease or loctite the seatpost bolt. Would this significantly change the measured tightening torque?
2. I did not put any grease, antiseize or loctite on the rail - should I do so? The seat has titanium rails.
3. Given the design of the seatpost has a leaf arrangement, could it be possible that this kind of design is just prone to squeaking under heavy loads? I bought it because it has a good reputation for NOT squeaking on the reviews I read.
4. If it turns out that I need to overtorque the seat collar to kill the squeaking, what might be a safe margin? Currently it is set to 5 N.m as recommended on the collar. The seatpost doesn't appear to be slipping after one ride and the seat hasn't move in the rails either.

All suggestions welcome!
 

schred

Likes Bikes and Dirt
Looks like that post is designed to flex a reasonable amount around the saddle area so I'd be looking there first on balance of probabilities, esp as it looks like there's a quite a few places for small movements given all the touching surfaces - washer under bolt head, post to clamp, clamp surfaces, and underside of that retaining lug on top. I'd give them all a clean and light coating of whatever grease you think is most appropriate and see where that takes you.

Mixed views on whether loctite affects torque ratings, I've seen it mentioned they say used dry ratings (all torque values are dry btw unless mentioned otherwise), and other sources where it's considered a lubricant. In either case, don't go over.
 

Binaural

Eats Squid
Check your frame very carefully for cracks.
By coincidence, I did this last week. I got the frame custom made for me about 5 years ago, and I though it was about time for a clean and inspection to make sure that nothing was going wrong. All in good order, as you'd expect given the visual quality of the welds.
test.jpg
 

Binaural

Eats Squid
Looks like that post is designed to flex a reasonable amount around the saddle area so I'd be looking there first on balance of probabilities, esp as it looks like there's a quite a few places for small movements given all the touching surfaces - washer under bolt head, post to clamp, clamp surfaces, and underside of that retaining lug on top. I'd give them all a clean and light coating of whatever grease you think is most appropriate and see where that takes you.

Mixed views on whether loctite affects torque ratings, I've seen it mentioned they say used dry ratings (all torque values are dry btw unless mentioned otherwise), and other sources where it's considered a lubricant. In either case, don't go over.
Good advice on the fittings. I am wondering if the flex is causing some rub on the bolts as well as the fit through the slot was reasonably tight.

Yeah, I agree on the mixed views about the torque settings. Most seem to suggest using the dry rating, but a few people have checked the tightened position against dry tightening and found it quite different. I guess you are recommending that I don't overtighten at all on the seat clamp?
 

Spike-X

Grumpy Old Sarah
By coincidence, I did this last week. I got the frame custom made for me about 5 years ago, and I though it was about time for a clean and inspection to make sure that nothing was going wrong. All in good order, as you'd expect given the visual quality of the welds.
That's some exquisite workmanship right there.

How about the bit where the seat goes in?
 

stirk

Burner
It's probably that strange seat position mechanism not the post in the frame. Good luck finding the squeak.

The welds on the frame are amazing and the best I've ever seen!
 

Travis22

Likes Dirt
I put a little bit of grease on the seat rails where they contact the seat post clamp.

That said the few times ive noticed a creak its actually been resolved with a couple drops of oil into the mould on the saddle where the rails attach. I just put a couple little drops of oil onto the rail near the ends and tip the bike so the oil runs into the ends.

Travis.
 

pharmaboy

Eats Squid
If you can change the saddle out, I'd try that to eliminate the saddle as a cause. Personally, I bought a torque wrench and started using it, then found most components were less than tight, so I stopped using it and tighten things till they do not move.

In an insustrial context I suspect torque ratings have some empirical and engineering reasoning, in cycling, they just make shit up, and print it. Witness the torque specs on both my bikes changing between models (upwards of course) - on the Niner, the torque spec increased 2 1/2 fold!
 

The Duckmeister

Has a juicy midrange
Grease all contact points of the post head assembly. Also spray/inject some form of lubricant around the attachment points of the rails to the saddle shell.
 

Binaural

Eats Squid
All I'm seeing is pressfit bottom bracket...
That's all I hear too. That's the dumbest decision I ever made while specifying the frame. Might be nice if I had included disc brake tabs but those were pretty early stage when I planning it.

Pharmaboy - I see a lot of semi-random specification of bolt torques (I manage a design team which includes a lot of mechanical engineers). A lot of the time bolt torque is not chosen in a scientific fashion at all, but by setting a torque that is enough, but minimises the risk of stripping when being done up with power tools.
 
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Flow-Rider

Burner
That's all I hear too. That's the dumbest decision I ever made while specifying the frame. Might be nice if I had included disc brake tabs but those were pretty early stage when I planning it.

Pharmaboy - I see a lot of semi-random specification of bolt torques (I manage a design team which includes a lot of mechanical engineers). A lot of the time bolt torque is not chosen in a scientific fashion at all, but by setting a torque that is enough, but minimises the risk of stripping when being done up with power tools.
How can you set a desired torque limit on power tools, the only thing you can do is guess what the max figure is going to be which is open to a lot of variations.
 

Binaural

Eats Squid
How can you set a desired torque limit on power tools, the only thing you can do is guess what the max figure is going to be which is open to a lot of variations.
We use calibrated torque assembly wrenches, which are a lot more precise than construction tools but also more costly and have to be tethered to a bench. For simplicity's sake we try and limit the number of torque settings the operators have to use to a handful of pre-set values so the operators don't have to dick around setting dials etc. when assembling parts.
 

Flow-Rider

Burner
We use calibrated torque assembly wrenches, which are a lot more precise than construction tools but also more costly and have to be tethered to a bench. For simplicity's sake we try and limit the number of torque settings the operators have to use to a handful of pre-set values so the operators don't have to dick around setting dials etc. when assembling parts.
I've snapped a lot of tools from trying to undo automotive bolts on brand new cars and trucks over the years. Most things are done to a price these days with automated machine and dry threads, I see on some of the shows they do a final check by hand on the important parts. A lot of memo's used to go out to check for loose bolts on brakes and suspension parts.
 

Binaural

Eats Squid
So, a little update. Last night I

1. Reassembled the head of the seatpost with grease on the washers and spacers, carbon assembly paste on the seatpost head and the threaded retention bar that holds the seat rails clamp together, with loctite on the inside thread of the retention bar. I didn't put any assembly paste between the seat rails and the clamps for now.
2. Slightly rotated the seat in the collar to keep it straight.

All of these changes have affected the creak not at all (initially yes, but came back 5min after leaving the house). For good measure I also gently overtightened the seatpost collar and the seat fixing bolts 25 mins into my ride to work to see if that helped at all. Again, no audible difference.

Does anyone have any other ideas about the cause? When I look closely at where the seat post clamps onto the collar, there does seem to be a tiny bit of flaring around the clamp. I measured the old seatpost with vernier calipers before buying, and I am confident it's the right size, but IIRC the new seatpost was slightly thinner by 0.05mm. Could this be enough to cause a creak?
 

Binaural

Eats Squid
One thing I have seen mentioned elsewhere - apparently it is possible for a seatpost to reach too far down into the frame into an area with looser internal tolerances. Has anyone else encountered this? I have also read of people wrapping a turn of electrical tape around the post to try and damp down the noise; this sounds like rather less than a good idea to me.
 

Flow-Rider

Burner
What brand and model of seat post and saddle are you using ? I've got a Bontrager carbon post with the one through bolt in the saddle clamp and it squawks all the time if I don't lube the rails in the clamping area. If you can, try swapping the parts out one by one to see if you can eliminate it.
 
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