Seatpost Failure - Pics and whyyyyy

[maximus]

Rough ride into work this morning.

I was descending the long hill before the Key Bridge into DC when suddenly CRACK - no more seat. I early lost it and ate pavement. It was wet out and I was on the fixed gear - so there was no nice coast to ride into. I feel very lucky to be OK. Fortunately, I had the Brooks in a plastic bag tied around the post because of the rain - so it just hung there.

Obvious culprits are possibly over tightening the bolt and the setback on the saddle putting strain on the post. I have put over 1k miles on this thing - glad everything was OK, but I am bummed to be out a beautiful seatpost.

What you guys think?

[jpw]

How old is it?

[Ti Designs]

How tight the bolt was may have had something to do with the failure, but the root cause is what's called a stress riser. It could have been a scratch or ding in the aluminum from the back, or one of the serated lines from the clamp surface itself.

I have my own seatpost failure story. At the top of Mt Washington the seatpost on my Vitus broke off. The rest of the climb, including the 22% grade was out of the saddle. It hurt a lot, but I'm pretty sure sitting back down would have been worse.

[AngryScientist]

maximus weight = ?

[avalonracing]

Man, those Brooks saddles really are heavy.

[Peter P.]

Ti Designs has the best analysis of what possibly sourced your seatpost failure.

I am prejudiced because when I read your post, I assumed you had an alloy seatpost with a press-fit head or a carbon post with same, and I dislike both designs because of the failures I've seen.

Your Campy post has a one piece shaft/head so there was no failure of an interface. The failure you experienced was a pretty freak thing.

Now let me give you the parent lecture: If you were riding a single speed or geared bike, you would have had a better chance of not eating the pavement. Fixies belong on the track, or underneath hipsters so Darwinian Law can work its magic ;-)

[RPS]

I can't see the picture clearly enough, but looks like failure may have started at top and fractured down from there. No doubt saddle all the way back doesn't help since it puts the top of failure area in tension, which is the way I'd expect the failure to start.

Another "possible" factor may be if you do lots of fast spinning in training which makes you bounce on the saddle. When I was testing my frame design I found that significant bouncing in saddle places high vertical forces on saddle/seatpost compared to normal pedaling and other movements. And compared to occassional large bumps, bouncing is repetitive which could easily lead to fatigue. Just a thought if you train at high cadences on your fixed.

Pictures looking directly at both sides of failure would help.

[maximus]

maximus weight = ?

About 180 on the dot.

Sorta creeped out by whole thing. I polished the seatpost - so I got pretty familiar with the surface and never saw any deep scratches or cracks.

[Louis]

Have you owned the s/p since new, or did you buy it used?

[maximus]

appreciate all the responses. all seem dead on. I was spinning out down a hill and had just gone up a ramp (its a sidewalk/path). My bounce was definitely the final blow the the post.

I am concerned because I don't want this to happen again. My saddle is pretty set back - but it is in the position that feels right for me. Not sure that is the issue though... Obviously its placing a lot of stress on the seatpost setback.

[maximus]

Have you owned the s/p since new, or did you buy it used?

Bout it used off this very forum. Everything seemed just fine when I got it.

I did de-anodize and wet sand and polish. It's hard for me to imagine how that would affect structure of the post - but seatpost engineering isn't my world.

Thanks again for everyone's insights.

[Louis]

Bout it used off this very forum. Everything seemed just fine when I got it.

Unless it's already cracked, you can't see fatigue damage. It then becomes a question of how quickly the crack propagates to critical length.

Unless you buy it new, you have no idea what happened in a previous life.

Replace it with a new one and forget about it.

[TimmyB]

I'd be lying if I said my inner weightwennie isn't going "see retro grouches, carbon seatposts aren't the only material that can break while riding!"

And campy no less! Should have bought SRAM :D

I kid I kid.

In any case, I attribute it to a glitch in the matrix. Glad to hear you're OK.

[eddief]

just kidding. Glad you were not hurt and still have YOUR vitals intact even if you have a busted post.

[avalonracing]

Bout it used off this very forum. Everything seemed just fine when I got it.

I did de-anodize and wet sand and polish. It's hard for me to imagine how that would affect structure of the post - but seatpost engineering isn't my world.

Thanks again for everyone's insights.

Holy crap, when you said that you bought it here on the forum I thought to myself, "Hey, I sold one like that here on the forum about a year and a half ago in my "This is how parts sitting around my basement should look" sale. Well, I checked my old posts and it seems that you bought a 25.0 Campy post from me (and here I am mocking the weight of your saddle in an early post on this thread).

If this is the post you got from me I can tell you the following: I think that is a post that I bought from Colorado Cyclist (again I think) and that I used it on my Vitus for a few thousand miles. I'm only about 170lbs on only used it on the road.

If it was ever overtightened it was purely by accident as I'm incredibly strong and don't know my own strength.

Sorry and I'm glad that you are okay. On the bright side you only bought it for $15... Shipped. :beer:

[weiwentg]

I'm only about 170lbs on only used it on the road.

If it was ever overtightened it was purely by accident as I'm incredibly strong and don't know my own strength.


It's all your fault, then. "Only about 170lbs" indeed.

[maximus]

Hey Avalon Racing - No worries! It's actually not your post - thought I still have yours (obviously I have an affection for aero Campy posts - though maybe no longer ;)

Still waiting for the right french bike to show up for your post. Sorta bought it on a whim in hopes it would be the seed for my long fantasized about rando build.

[Ti Designs]

Still waiting for the right french bike to show up for your post.

If you're having problems with failures, switching to french stuff may be a step in the wrong direction.

[ultraman6970]

WOW, 1st time i see this ever. I have seen the rails clamps split in half, have see bolts split in a half but never saw one like this one. Well the good news is that u are ok.

Look at discoloration, im not that sure but looks like in the top the color is darker?? that could be indication that the seatpost was already cracked since who knows when.

If you want to play safe, nitto or shimano.= seatposts last forever.

[bfd]

If you want to play safe, nitto or shimano.= seatposts last forever.

Nitto, may be, but Shimano, not necessarily. I have a Dura Ace 7410 seatpost. Bought it used. Nice and light. It worked well for a while, but now it "turns" on the head of the post. Is there a fix? I've tried putting a little superglue on the head part, but am not sure it got down far enough. Let me know if anyone knows of a way to fix it!

[Dekonick]

Man, those Brooks saddles really are heavy.

HAHAHA! Awesome! Post of the day!

[Dekonick]

I agree with the Nitto advice... Velo Orange also makes some robust posts. I do like the look of the vintage Campy posts... I recently sold 3 of them... WHEW!

[Dekonick]

appreciate all the responses. all seem dead on. I was spinning out down a hill and had just gone up a ramp (its a sidewalk/path). My bounce was definitely the final blow the the post.

I am concerned because I don't want this to happen again. My saddle is pretty set back - but it is in the position that feels right for me. Not sure that is the issue though... Obviously its placing a lot of stress on the seatpost setback.

I had my Bedford designed around my Brooks... to avoid the stress of a lot of setback.

I feel much safer... especially now!

[Marcusaurelius]

I think any seatpost can fail but a used seatpost with unknown history suddenly makes me very nervous.

[rugbysecondrow]

I broke a seat post 3 miles I to a 15 miles mtb leg of an xterra triathlon. It didn't brake clean off, but the bolt would secure ao the saddle freely rolled forward and back. If was either out of the saddle or centered. It was a crappy race. Luckily I am going for a redo this summer.

[ultraman6970]

Epoxy should work like a charm.

Nitto, may be, but Shimano, not necessarily. I have a Dura Ace 7410 seatpost. Bought it used. Nice and light. It worked well for a while, but now it "turns" on the head of the post. Is there a fix? I've tried putting a little superglue on the head part, but am not sure it got down far enough. Let me know if anyone knows of a way to fix it!

[Kontact]

You seat is pretty far back on it's rails, and Brooks have pretty long rails. So I would wonder what role (if any) leverage played in weakening or finally breaking the post.

[mister]

Hey Avalon Racing - No worries! It's actually not your post - thought I still have yours (obviously I have an affection for aero Campy posts - though maybe no longer ;)

Still waiting for the right french bike to show up for your post. Sorta bought it on a whim in hopes it would be the seed for my long fantasized about rando build.

yeah i was gonna say whats even weirder than that post breaking is a mercin with a 25.0 post...

i'd just lose the brooks or get one of those VO posts with extra setback. maybe that would allow you to clamp a little closer to center on the rails.

[PaulE]

NJS means approved for use in Keirin gambling - component failure is unacceptable when money is on the line, or something to that effect, in Japanese! :beer:

[MattTuck]

Brooks... paying for the privilege of riding with a plastic bag over your seat when it rains.

:rolleyes: :rolleyes: :rolleyes:

[martinrjensen]

Look at the crack. If part of the crack is dark, and some of it bright, the bright is the most recent crack, the catastrophic failure one. The dark part was present for a while. It would be good to see a pic of the cracks facing on.

[maximus]

I had my Bedford designed around my Brooks... to avoid the stress of a lot of setback.

Amazing. I thought I was crazy - but not only does the saddle feel right set back so far - it also "looks" right.

I will snap a better pick of the fracture tomorrow. Its a pretty clean break.

Fortunately (in line with some advice here), I have a Nitto Crystal seatpost as backup that will go on tomorrow.

Very glad to be ok - we all know the direction that seatpost was aiming and happy not to have had it surgically removed. I did get some funny looks as I did my last three miles through downtown DC sans seat. The post was bound for my Merckx build this weekend. Oh well...

[maximus]

Brooks... paying for the privilege of riding with a plastic bag over your seat when it rains.

:rolleyes: :rolleyes: :rolleyes:

Truth. :rolleyes:

[Dekonick]

Brooks haters - just go play at the weight weenies arena...

I know that my important parts will be hard when they need to be... will yours???

The plastic bag is a crappy solution... I agree. I still do it myself... :o

[rugbysecondrow]

Brooks haters - just go play at the weight weenies arena...

I know that my important parts will be hard when they need to be... will yours???

The plastic bag is a crappy solution... I agree. I still do it myself... :o
Brooks + fenders = Good

[pdmtong]

Unless it's already cracked, you can't see fatigue damage. It then becomes a question of how quickly the crack propagates to critical length.

Unless you buy it new, you have no idea what happened in a previous life.

Replace it with a new one and forget about it.


I'm with louis...&(*& happens. glad you are ok. I have a WTB SST98 mounted similalry far fwd on the rails on my mtb. no issues with a EC70...it may stress the post more..but i would think th e saddle rails would bend before the post head snaps...

[Chousen One]

Brooks haters - just go play at the weight weenies arena...

I know that my important parts will be hard when they need to be... will yours???


Uh... what?

[Louis]

Uh... what?

Apparently Brooks saddles protect against CIED

(Cycling induced erectile dysfunction, a term I just invented)

I don't know if that's true or not.

[Dekonick]

Apparently Brooks saddles protect against CIED

(Cycling induced erectile dysfunction, a term I just invented)

I don't know if that's true or not.

I don't know if they do or not... but I never find myself with any typical complaints you hear from regular users of ass hatchets.

[snah]

Apparently Brooks saddles protect against CIED

(Cycling induced erectile dysfunction, a term I just invented)

I don't know if that's true or not.

CIED, that just became a forum classic!!! :beer: :beer: :beer: