Hospitals are boring

[jules21]

I have the contacts though if you purchased overseas, you can forget contacting the Aussie FSA importer SCV Imports as they have no warranty obligations.

i might question that Christopher - they would still have an obligation to supply goods fit for purpose. i don't imagine they can delegate that responsibility. while they may not handle the warranty claim, they must decide whether to continue supplying the component to market.

[gabrielle260]

I had installed one of those seat posts on my Lynskey rigid 29er and the post cracked at the point it entered the seat tube. This was despite using the carbon assembly paste that FSA provide and a torque wrench to tighten the binder bolt to the much reduced torque. Fortunately I heard the crack of the post as it went and was able to avoid injury.... unlike Skull!
I sent the post back with photos to Chain Reaction and they sent it onto FSA who eventually instructed CRC to send me a warranty replacement.
I had offered it for sale on the forum but had no takers. As I type this, it is sitting on the table, still in it's box. I think I will just put it away and forget it - wouldn't want to sell it onwards and then have something like this happen to the forum member who bought it!
Andrew

[Nobody]

In the other thread [url]Snapped the saddle rail bolt on my seatpost[/url] TLL says he'd snapped 5 seat post
bolts, but had not snapped any since turning to Thomson seatposts. Most of the Thomson ones have 2 bolt
designs.

Nobody can break things like TLL, so if he says the Thomson ones are the good oil, that's good enough for me.

Thanks for the reply.

Ah yes, TLL the unofficial BNA stress tester.

No doubt Thomson have a good reputation for quality.

There are probably some others out there too. I've got a Nitto S-84 CrMo seatpost with a two (large) bolt clamp. I doubt I'd ever break it.

For those who are thinking it's a good idea to tighten up their seat clamp bolts frequently, the Snapped the Saddle
rail thread has a post and link to an example where too much torqueing of the bolt has caused necking (thinning)
of the bolt and ultimately a fracture. Don't expect to get a warning sign like a creaking saddle.

This is assuming that clamp bolt(s) aren't strong enough. Unfortunately likely in many cases from the results we are seeing. Another option would be to get a higher strength bolt. But then the top clamp could just as easily let go, especially if made of Al without steel nut inserts and in theory, you'd have to upgrade the nuts as well. Probably not that easy to do. Probably easier to just get a better seatpost.

Might be a job best done with a torque wrench and manufacturers spec, and a regular inspection of the bolt. Just a guess here, but I'm going for 6 monthly or 5000 km, say.

If you can get a manufacturer's spec. I just tighten until I can feel a bit of bolt stretch and I'm done. That way the only likely thing that can happen is the saddle slipping in the clamp.

This is why I'm not into weight weenie-ism. When a single bolt failing can do so much injury, it's not worth downgrading strength to save a few grams IMO.

[cycles gitane]

No jokes from me, but best wishes for a speedy recovery.
Last year I visited a friend in hospital who fell face first onto the road and broke both front teeth.
Your injury is a similar nightmare scenario.
Get well soon.

cycles gitane

[Howzat]

Skuill, at least you can take consolation in the thought that your rear end is now famous on the internets.

[MichaelB]

i too had a FSA K Force seatpost crack, but the failure was a crushing of the walls.

To be fair, I think the fact that I had to give the seat clamp a bit of willie to stop it slipping contributed.

Fortunately, I noticed before ultimate failure

[sogood]

... What I am really scared about is going to do my business, as that will hurt. I am also on laxatives to try and loosen things up hopefully.

As I earlier suggested, you should have a big tube of local anaesthetic containing lubricant available (readily available at your local pharmacy). Without it, you'll be too scared to do your business, and the result of holding back is constipation and hard stool. Apply liberally to numb down the region and take plenty of stool softener/laxatives. keep up with your Panadol too. And make sure you take a shower after each sitting to make sure the area remains "clean". Then pad dry the area, apply the lub and let it air.

BTW: You'll lose weight over this period. That's a good thing in terms of power/weight ration.

[ldrcycles]

No jokes from me, but best wishes for a speedy recovery.
Last year I visited a friend in hospital who fell face first onto the road and broke both front teeth.
Your injury is a similar nightmare scenario.
Get well soon.

cycles gitane

As someone who has lost 3 front teeth in that fashion, i can say i would much rather that than what happened to skull, doesn't bear thinking about.

Best wishes for a speedy (and as painless as possible) recovery.

[twizzle]

Ow!

Jeez mate, that's a pretty extreme way to avoid work!

(FWIW, I use Thompson posts, but the "ears" the bolts go through have been known to crack and break off if over-torqued, so I always use a torque wrench).

Sent from my iThingy...

[isabella24]

Glad to hear you are home and wishing you a speedy recovery.

[the_big_fella]

wishing you a speedy recovery Skull.
That sounds like a horrific scenario.
your experience will make me, and many others here, fully appreciate the fine work of a properly functioning seatpost.

[skull]

(FWIW, I use Thompson posts, but the "ears" the bolts go through have been known to crack and break off if over-torqued, so I always use a torque wrench).

Sent from my iThingy...

oh, they are the same bolt set up as the FSA's I have and that is what happened. The thing is the design of the FSA wit set back made it unable to use my torque wrench.

[CatCanRide]

Just read this thread and couldn't stop wincing.
Glad it wasn't the worst case scenario for you Skull.

Wishing you all the best for a good recovery.

[Nobody]

(FWIW, I use Thompson posts, but the "ears" the bolts go through have been known to crack and break off if over-torqued, so I always use a torque wrench).

Sent from my iThingy...

oh, they are the same bolt set up as the FSA's I have and that is what happened. The thing is the design of the FSA wit set back made it unable to use my torque wrench.

So are you saying one of the "ears" of the FSA clamp broke off?

Large setback seatposts are hard to find these days. If you don't want another FSA K-Force Light (which I also considered) then VO do a 30mm offset seatpost in Al with a smaller clamp. The Nitto I listed above is officially 37mm offset but as the clamp is bigger than the VO, so the actual offset affecting the saddle rails is the same as the VO. I know this because I own both. There is also a Kalloy carbon post with a 30mm offset. If you know of any other large offset posts, please let me know.

[skull]

picture of post as you can see front bolt missing




The bolt where it snapped. It wasn't even on the lug but half way along

[Nobody]

Thanks for the clarification.

So have you thought about what you are going to replace the seatpost with? Have you considered trying to get stronger bolts? Might be a cheap fix.

[wombatK]

Home.

Looks like 6 weeks off the bike to recover and 2 weeks off work at least.

Anyway the seat post in mention was an FSA K-Force with 32mm setback.http://www.wiggle.co.uk/fsa-k-force-light-carbon-seat-post-2011/

I have the same post on my mountain bike, it also had the bolt snap on the seat clamp. Luckily when that happened I didn't have all my weight on the seat so just stood up. Unlike the other day and I was sitting up on the seat.

Thanks for posting details and photos of the seat post.

So it only took failure of one of the two bolts to give you this grief - blows my suggestion that a two post clamp is inherently safer right out of the water. And we need to look for an alternative idea about how not to end up with your troubles.

The set-back design of the post probably puts more bending stress on the front bolt of the clamp, as your whole weight has been moved aft of the post by the set-back. So it might be more likely to fail from the bending fatigue issue suggested in the ekib's post on Snapped the saddle rail bolt on my seatpost and the post on Engineering Materials. And with your weight that little bit further back, your chances of avoiding the backside-on-wheel or remains of seat-post aren't looking good.

Can you post an end-on shot of the broken bolt (both sides) like those on the EM post ?

From the photos you've posted so far, it appears the bolt has snapped on the threaded section - was it near the junction between the top and bottom parts of the clamp, or deeper within the seat post ?

I don't know if I'm too naive, but I'd previously thought FSA products were decent quality - it's not like you had a no-name generic chinese clone item. Definitely worth reporting it to them as suggested by the doc's, if only to test how decently they stand behind their products. If they ask you to send the broken bolt to them, maybe get it assessed independently first (and let them know that).

On the more positive side, you've had a good outcome from the surgery and while you're not out of the woods, your fitness will serve you well and help you get through this quickly.

Have you considered trying to get stronger bolts? Might be a cheap fix.

If, with all their engineering expertise, FSA didn't get it right, how's skull going to work out just how much stronger a bolt is needed ? The bolt and clamp is a fastening system, and focussing on strengthening just one side of it might not be
such a wonderful idea (e.g. other parts of the clamp could fail).

How does skull decide what will be a "strong enough" bolt if he doesn't have a thorough knowledge of material science and mechanical engineering of such systems ?

FWIW, the problem might have been a manufacturing defect in the bolt - rather than an inherent design weakness. It needs a little more investigation by a materials expert to tell us what the underlying weakness was.

At the moment, I'm glad I've been lazy about trying a set-back seat post as an option to take some load of my forearms (and relieve a little golfers elbow).


Cheers

[AUbicycles]

i might question that Christopher - they would still have an obligation to supply goods fit for purpose.

I agree on that

[twizzle]

So the head broke off the bolt??!!!

Design fault. Fatigue failures in bolts should not be at the head, they should only be at the root of the first thread as it enters the "nut" as it's the weakest part of the bolt. The design has to be deficient and allowing a bending load on the bolt head or the bolt head was missing the radius from the shank to the neck or the washer under the head wasn't radiused. But something is wrong there.


With the Thompsons they don't radius the edge of the "ears" at the top of the post and that's where the fatigue crack starts, but the failures are rare.


Edit: just picked up on the comment about "halfway along the lug". Did it break where the thread started?

Sent from my iThingy...

[Nobody]

Have you considered trying to get stronger bolts? Might be a cheap fix.

If, with all their engineering expertise, FSA didn't get it right, how's skull going to work out just how much stronger a bolt is needed ?

First I wouldn't necessarily blame the engineer. I'd blame the company. The engineer probably designed something originally that TLL could ride for 20 years. Then the bean counter said no.

The bolt and clamp is a fastening system, and focusing on strengthening just one side of it might not be such a wonderful idea (e.g. other parts of the clamp could fail).

But other parts didn't and so I'm focusing on fixing the actual fault. If exceeding the fatigue limit in steel is considered repeatedly exceeding half the yield strength. Then increasing the tensile strength of the bolt and therefore its yield strength by the same margin, will mean the bolt rarely experiences stress above half the yield strength and therefore should never break in the lifetime use of the seatpost.

If posts with this much setback were common, then it would be just a matter of buying another brand or model. But as shown in a previous post of mine above, this isn't the case. Therefore making more of a case for a repair.

How does skull decide what will be a "strong enough" bolt if he doesn't have a thorough knowledge of material science and mechanical engineering of such systems?

If in doubt he could ask an engineer at a engineering supply shop (eg. bolt & bearing supply). If he is mechanically minded I'm sure he can figure it out with the vast amount of information online.
http://en.wikipedia.org/wiki/Screw#Mech ... ifications

FWIW, the problem might have been a manufacturing defect in the bolt - rather than an inherent design weakness. It needs a little more investigation by a materials expert to tell us what the underlying weakness was.

All the more reason to just fix it and move on. But if I were Skull, I'd be getting the strongest bolts I could find for the application. I'd probably try to upgrade the nuts too, but it looks much more difficult due to the shape. Although you could probably make some from some high quality bar.

[doggatas]

Skull ol' boy couldn't let you be injured all on your lonesome, 60km/h, front tire blow out, doesn't tickle.

Wishing us both a speedy recovery.

[gabrielle260]

Skull ol' boy couldn't let you be injured all on your lonesome, 60km/h, front tire blow out, doesn't tickle.

Wishing us both a speedy recovery.

Ouch!!!!!
Hope you are back on the bike soon,
Andrew

[fatdudeonabike]

My God skull, thats the most painful thing I can imagine.
And here has been me feeling sorry for myself - I sat in hospital for 7 hours over 2 days this week after a bike accident that tore my quad.
After reading your horrific story, I feel soft for not going and and riding with said torn quad. (Although I did ride 400m home with a torn quad after the crash)

[skull]

Skull ol' boy couldn't let you be injured all on your lonesome, 60km/h, front tire blow out, doesn't tickle.

Wishing us both a speedy recovery.

Obviously the team of skulldoggary was to much for the world to handle.

[InTheWoods]

Why oh why do I have to keep reading this thread.

Every time I do, my nether regions tingle in sympathy and try and run away

Ditto, + a gazillion.....
Andrew

My "cheeks" are still firmly clenched together...