Broken seat post

mackerooney

Just as I left the house on a spin this evening, heading for Glencree, I heard a snap and looked back to see my saddle on the road.
i got a bot of a shock - what if this had happened on the top of the hills, how would i get down?
On reflection - why would this happen as the bike is only 3 years old.
In anyones experience is this common? Should I bring it back to the shop?
Thanks.

Húrin

carbon?

mackerooney

Bontrager carbon.

Lumen

Glad you're OK.

Could have been worse.

Tackleberry wrote:

I was descending a rough stretch of road at about 55kph, working my way through the group, when the bike went from under me, I went to the side and to the front of my bike - thumped down onto the ground, smacked my head, then skidded along the road, smacked my head again, and came to a stop, dazed and confused, at first I thought I was dreaming or something, but then the pain kicked in. My bike was about 20 feet further down the hill, I immediately saw that my saddle and half my carbon seatpost was back up the hill, which was odd...

One of the cyclists in our group happened to be a doctor and he was great, as were many of the other guys, they calmed me down and checked me over, needless to say I was in a bit of a mess, torn clothing with patches of blood seaping through, my modesty was barely protected aswell! My hands were fcuked, so I got a garda escort to Nenagh Hospital and 2 days later the result is a whole load of road rash on most of my body, some chipped teeth and a broken thumb and badly cut fingers, but I actually just feel lucky - my helmet is destroyed, and I'm 100% convinced it saved my life coz I even have a bump where my helmet hit my head! 1st crash in 12 years, and it was a biggy! Very angry about the seatpost failing, won't be getting another, but its left me quite wary of all things carbon as my entire bike is made up of the stuff! Front Zipp seems to be fcuked too. Some exit!!

mloc123

You over 90kg? I think most carbon seatposts have weight limits... I used to be concerned about mine anyway.

mackerooney

would be in and around 90kg.

Reading that post I am lucky.

I am assuming that the replacement should not be carbon? Any suggestions?

Lumen

mackerooney wrote: »

would be in and around 90kg.

Reading that post I am lucky.

I am assuming that the replacement should not be carbon? Any suggestions?

This or this. Not cheap, but light and probably strong.

AFAIK titanium does not suffer from fatigue like aluminium alloy.

Or you could get a steel one, but it will be heavy.

edit: I have neither, but they look real purdy

mackerooney

Lumen wrote: »

This or this. Not cheap, but light and probably strong.

AFAIK titanium does not suffer from fatigue like aluminium alloy.

Or you could get a steel one, but it will be heavy.

edit: I have neither, but they look real purdy

Thanks for that. Current one was straight but I will have a look in a shop at the set back to see if its more suitable.

Just to confirm - this is common enough and there is no point in going back to the shop with a three year old seat post?

mackerooney

Sorry - should have included in the last post - should I check the post on the handlebars? is this something that can also fail?
Dont want to appear paranoid

Lumen

mackerooney wrote: »

Sorry - should have included in the last post - should I check the post on the handlebars? is this something that can also fail?
Dont want to appear paranoid

Do you mean the stem?

Those are usually OK, but if you want to be paranoid aluminium handlebars can break through fatigue - I've seen recommendations that you change the bars every couple of years, although many people don't.

You can't get titanium drop handlebars (you can get straight ones) but if you're paranoid you can get steel ones.

Then there's your forks....

DirkVoodoo

Everything fatigues, it all depends on the stress is put under.

In general usage, unless you ride the crap out of it, an Aluminium bike will last a long time. Yes, it has not fatigue limit, so unlike steel or titanium, it will eventually fail, but I would imagine that for most people this will be past the point at which they upgrade. At any rate, you will more than likely experience some amount of plastic deformation before failure in an Aluminium post, so you will know (hopefully) it is on the way out. Unlike carbon, which just goes crack! Of course, the failure mode depends on lots of things, so unless there is some published testing on seatposts, you can't really take what I am saying as anything more then my opinion.

Aircraft grade titanium alloy like the Van Nicholas post there should function very much like a steel alloy seatpost, except it is obviously lighter, so it is superior on a weight basis and obviously for its corrosion resistance.

If you can afford titanium go for it, otherwise aluminium is fine.

Húrin

screw carbon. never going to use it.

(famous last words)

humbert

Why are horror stories about forks breaking not more common since they are very often carbon and there is absolutely no way you are walking away from it??

DirkVoodoo

Well, you need a crack generally, and unless you damage it through crashing, it's harder to crack a fork because there is less weight on it.

It's all very much of a simplification the way I'm getting at it, like I asked a friend who is MUCH more intelligent than me earlier on: "it depends on lots of things"

humbert

So there's generally some forewarning...

DirkVoodoo

Eh, if it's carbon, just clean your frame often and look for cracks or anomalies in the frame and fork. I don't know what the actual failure rates are for various parts and manufacturers, but I would say you should probably be mored worried about slipping in the shower, falling off a ladder, or lots of other things

humbert

I shall make a point of worrying about those things too!


Seriously though, I know it mustn't happen often but it still creeps into my head when I'm barrelling down a bumpy hill. I'm sure it will pass with more experience.