If it ‘aint broke etc.

My Thomson seatpost in probably 12 years old (possibly rather more) and now on its 3rd bike; it just keeps on working and I tend to forget about it.

The thing is aluminium has a finite fatigue life so should I be looking at replacing it? I vaguely remember reading dire warnings in my copy of Zinn and the Art of Mountain Bike Maintenance that seatposts and bars (and possibly stems) should be replaced every 3 years (I also vaguely remember this assertion being questioned on here as somewhat alarmist considering the lifespan of some aluminium frames can measured in decades).

So, should I be worried about the age of my seatpost?

No

Mine is coming up to 10 years old (although for a year or so I used a dropper instead of my Thomson). I’m not too concerned about it, in part because it’s on my commuter so even catastrophic failure is unlikely to put me in that much danger.

I did, on the other hand, replace a pair of bars that were 5 years old when I found a crack in the stem faceplate (neither the bars nor stem were Thomson)…

The fatigue life depends on how it’s been loaded during that life.  Thomson seatposts are quite well built, so it’s probably fine. You could email them.

I’ve got a few thompson posts.

One had one of those horrible seatpost mounted pannier racks on it that swung about and gouged big lumps of aluminium out of it which the internet engineers would cry out are sure to be stress raisers and cause imminent death of baby robins, children’s faces and kittens.

I still ride it without a second thought except for a bit of black electrical tape over the damage because I’m a tart.

Only seatpost I’ve ever broken was an EA70, which was almost new.

The Bonty Select that came with my ’05 Gary Fisher snapped after a year or so, the Thompson seat post that replaced it is still going strong several bikes/frames later.  Unfortunately it’s welded solid into the current frame so is unlikely to survive beyond this one (I have no plans to replace the bike).

I have a RaceFace seatpost from the mid nineties that’s still in use so I may not be the best person to ask.

[edit]

I also have two thomson seatposts that are over ten years old. hadn’t crossed my mind to change them.

That’s reassuring, cheers. On reflection I reckon the post is nearer 10 years old and it’s an Elite rather that the reduced weight Masterpiece so hopefully will continue for some years to come!

Still using my 1990 XT seatpost.

Which is steel.

On a rarely ridden bike.

should I be looking at replacing it?

No you’ve hardly used it. I’ve got original USE, X-Lite, Syncros and Ringle seatposts that are still going strong. Mind you back then they knew how to make a seatpost and this was all just fields. In fact yawn zzzzzzzzzzzz

I had a Syncros seatpost that was on my ‘94 RM Blizzard when I bought it (new).

It didn’t last long before it developed a bend, although I’m sure it would have just carried on like that and not broken.

No you’ve hardly used it. I’ve got original … X-Lite…

Ah, I remember my mate riding over a log and his X-Lite post went squirbb  (or whatever noise a bending seatpost makes). Many years ago and still the only seatpost I’ve ever seen die.