So I snapped my seat post clamp...

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McGilli
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by McGilli

I'm still high on caffeine after getting in from my ride so this might be wordy.
I was on a 300km solo ride today, and about 110km away from home I wanted to make a tiny adjustment with my saddle height. Anyways - when tightening the seat post clamp bolt i guess I torqued too hard and the clamp snapped in half. So...

Now - just some info - when I put my seat post into my frame (Ti post and Ti frame - but looks like ridged steel insert inside) - it literally took me 35 minutes, and about 2 litres of sweat. This was using grease, and after having cut down the seat post.

It's a HUGE effort to raise or lower the seat post even a couple of millimetres. I have a marker on my post where it enters the frame. I rode home the 110km - checking every 10km for the first while - and it never budged even 1mm the entire ride home. I really do not want to have to remove the seat post. Is there a clamp that can - stretch open and then be bolt shut? Maybe carbon? I have a spare alloy clamp here - but it won't stretch open at all...

My clamps have that lip on them - and i notice carbon ones don't.

Does that lip even matter? Options?

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kulivontot
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by kulivontot

Side-question, is the slot on the clamp supposed to align with the slot on the frame or go opposite it? I had an s-works clamp that clearly indicated they shouldn't be aligned, but snapped off a scott clamp tightening it that way last week.

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Calnago
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by Calnago

Is this a custom ti frame/seatpost? That is just too tight a fit first of all. You were able to ride 110km home with essentially no seatpost clamp and it didn't budge? I think you need to get that sorted out first. Are you sure the two are designed for each other?
In any case, I'd say the clamp is the least of your worries at this point. Do what you can now to completely remove the seatpost, clean it all up as well as the inside of the seat tube, and make sure the two are compatible size wise (determine why the fit is so tight). If you don't do this now you may find yourself with a seized or permanently galled seatpost/frame in the future at some point.
As for the clamp, no the lip doesn't really matter but man, what kind or torque were you applying to that thing, especially when it appears that 0 torque was needed. Only use enough torque to get the job done.
So, get that seatpost outta there now and sort out the frame/seatpost interface.
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xena
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by xena

I'm not familiar with Ti , but carbon you get galvanic corrosion and it can spread so if there is some kind of corrosion possible then definitely get your seatpost out . I'm sure the Ti experts will chip in.
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AJS914
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by AJS914

Maybe the seatpost was clear-coated thick creating the tight fit. I'd at least try some other seatpost to check the fit. Better yet, if you have a micrometer you could measure the seatpost and tube (ID).

McGilli
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by McGilli

It's all pretty standard. It's a Lynskey Helix Ti frame. The seat clamp is the one supplied by Lynskey. So the seat tube is 31.6, the seat post I bought is 31.6, and the clamp is a 34.9.

Here's where I post about putting the post in the bike:

viewtopic.php?f=10&t=140326&start=45#p1254247

So the frame's only a month old

PS. I was on the side of a mountain highway with huge tricks whizzing by - and lots of caffeine so I just didn't pay attention to how much torque I used when tightening the clamp - plus I was only 190km into a 440km ride at the time (which I cut short)

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Calnago
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by Calnago

Nothing standard about that inner seat tube surfacing. I've never seen an inner seat tube that was done like that. But it's clear to me that the post you have and the seat tube it's going in are a mismatch. Call Lynskey for advice. That seat tube almost looks like it's threaded from the picture, it can't be, but that's what it looks like. It's almost as if they forgot to do the final reaming. Ouch.
But nice setup overall.

I like that you were only 190k into a 440km ride. Just a short ride before lunch was it? :beerchug:
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mattr
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by mattr

Looks like they've only done a rough cut or more likely, used a broken tool, to do that seat tube.

McGilli
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by McGilli

UPDATE - seat post out. Took a couple minutes to get past the first 5mm then the rest actually came out pretty smoothly :) I do have another seat post from a MTB and tried that - and it slides in more easily.

I'll go and grab a clamp. Good to know that having the lip isn't important.

McGilli
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by McGilli

AJS914 wrote:Maybe the seatpost was clear-coated thick creating the tight fit. I'd at least try some other seatpost to check the fit. Better yet, if you have a micrometer you could measure the seatpost and tube (ID).


:thumbup:

Just tried putting the seat post back in and it just slipped right down practically. I guess it had some kind of coating on it or something that came off after the first insert....


Thanks everyone!

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Calnago
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by Calnago

I'd still call Lynskey. Regardless of whether it's carbon or metal, I've only seen smooth surfaces on the inside of the seat tube. And it's very puzzling how it just slides in and out easily now, yet you were able to ride over 100K on it with a broken seat clamp and no slippage whatsoever. And I know I said nice setup overall, but after going back and having a closer look at your thread, well... it certainly is a mismatch of looks... but you also said that's what you like about it, so good on you... you achieved it.

But that MadFiber up front? How can you descend with that thing in the wind? These are probably questions for your build thread.
In the meantime, if you do call Lynskey about those serrations on the inside of the seat tube, please report back with what they say. Just doesn't look right at all to me.
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CampagnoloRules
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by CampagnoloRules

I recommend Thomson seatpost clamps- super strong yet light. Only requires 3 N-m torque. No issues or slippage with my two Niner RDO carbon posts, and I weigh 190 lbs. Can't imagine how you snapped a seatpost clamp.

mattr
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by mattr

Won't be clearcoat. Op says it's a ti post.

Might be a tight seal. Creating an airlock. Had that on a couple of carbon bikes in the past. Taking the bottle cage bolts out "fixed" the issue.

McGilli
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by McGilli

Calnago wrote:I'd still call Lynskey. Regardless of whether it's carbon or metal, I've only seen smooth surfaces on the inside of the seat tube.


No it's supposed to be like that. The photo doesn't show it - but about 1cm farther down - the ridged insert ends - and then it's wider below that and u just see the Ti frame.

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froze
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by froze

CampagnoloRules wrote:I recommend Thomson seatpost clamps- super strong yet light. Only requires 3 N-m torque. No issues or slippage with my two Niner RDO carbon posts, and I weigh 190 lbs. Can't imagine how you snapped a seatpost clamp.


I kind of agree with the Thomson but I think you can spend less and get just as good of one, the Thompson weighs 18 grams, not the lightest on the market but they're not using alloy bolt and insert (sleeve), but rather steel from what I can tell in the photo which is better. Aluminum bolt and insert if tightened just a tad too much will break. I own a Lynskey TI bike myself and the supplied Lynskey collar sucked, I broke 2 of them at the bolt because it wouldn't hold my seat very well, so I tighten it a tad and snap the sleeve would break. On my Lynskey I bought a cheaper collar made by XLC it cost me $8 at my LBS and it works far better than the Lynskey ones did, so you can get one that works for less than the Thompson just depends on how anal you are about brand names. Be warned, the XLC weighs 4 grams more than the Thompson...oh no!

This is the model of XLC collar that I got: http://www.niagaracycle.com/categories/ ... An7-8P8HAQ

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