Thomson seatpost failure today

[Louis]

This really bummed me out because I was looking forward to a nice ride. As I rolled out the driveway onto the street I heard a loud "bang" and my saddle jerked backward. I figured it was the seatpost and hoped that it was one of the two tilt adjustment screws that had failed. Turn out that it was the front "horn" that failed almost exactly as shown in the pic below (pic's not mine, just something a Google search dredged up when I looked for an image of "Thomson Seatpost."

At least it had the decency to not fail 20 miles from home...

Usage info: Right now I weigh 181 lbs, and the max I've been when riding this is probably 187 lbs. Just road riding, no rough stuff or bouncing around in the saddle. I had my Regal clamped almost exactly in the middle of the rail adjustment range.

Anyone else ever have a similar failure? Clearly I'm not the only one.


http://files.myopera.com/badmadcyclist/albums/119928/Broken_Thomson_Elite_seatpost_2.jpg

[bkboom123]

well thats exactly what i don want to see. I am planning a hilly 70 mile ride tomorrow morning......this will surely be in the back of my head when i'm hopping on my thomson masterpiece :crap:

[godfrey1112000]

http://www.edgecomposites.com/seatposts.aspx

25mm set back is my brand

[130R]

http://www.lhthomson.com/gallery/Fatman1280.jpg

[thendenjeck]

crazy. i've seen carbon posts fold in situations like you describe, but that's a new one on me.

[Louis]

^^^^^^^^

130R - That's great that you haven't had any problems with your seatpost.

What brand is it? I need to try that instead - you've obviously put it through extensive testing. :p

[130R]

:butt:

[Don49]

That's scary. I use Thomson Elites on most of my bikes, road and mtn. No issues aside from being slightly undersized.

Any chance the clamp bolts could have been over torqued? Spec. on the Elite is only 60 in lbs per bolt, which isn't much. Masterpiece is even less at 45 in lbs.

Glad you didn't get hurt. A rider in my GF's club went off backwards when his CF post failed at the joint.

Note: I haven't been using a torque wrench here, but I'm going to start.

[dave thompson]

It's extremely unusual to see a Thomson post break. I'll betcha a dime to donuts that they'll warranty it for you.

[Louis]

Any chance the clamp bolts could have been over torqued? Spec. on the Elite is only 60 in lbs per bolt, which isn't much. Masterpiece is even less at 45 in lbs.

Don,

All my Thomsons are also Elites. No, I haven't been using a torque wrench but if it was to due to over-torquing it sure took a long time to fail. I haven't fooled with the adjustment of that saddle for at least a year, which means that it was most likely a fatigue crack that grew until there wasn't enough material left and then I got the final static failure.

This is a bad spot to have to use a torque wrench because when dialing things in you want to be able to adjust it while out on the road, but I agree, I think I need to consider using one.

[Volant]

I've never seen an elite break there; just glad you weren't far from home and not injured. Like someone earlier stated, Thomson would probably want to check that post out (and replace it).

[Don49]

This is a bad spot to have to use a torque wrench because when dialing things in you want to be able to adjust it while out on the road, but I agree, I think I need to consider using one.

Maybe Ritchey Torque Key, fixed at 44 in lbs. 4mm bit fits the Thompson.

http://www.jensonusa.com/store/product/TL295J00-Ritchey%20Torque%20Key.aspx
http://www.competitivecyclist.com/mountain-bikes/review-tool/Ritchey-Torque-Key_1216.html

[54ny77]

Bzzzzt, claim over! ;)



Usage info: Right now I weigh 181 lbs, and the max I've been when riding this is probably 187 lbs....

No, I haven't been using a torque wrench but if it was to due to over-torquing it sure took a long time to fail.

.... but I agree, I think I need to consider using one.

[soulspinner]

http://www.lhthomson.com/gallery/Fatman1280.jpg

:p

[wasfast]

Given all the Thomson seat posts out there, including many forumites here as well, I'd have to believe it's an anomaly. I have Elites on my rain and dry bike with zero issues over the years. Doubtful anyone else needs to worry unless Thomson is aware of a batch issue somewhere along the way. Not likely.

[ahumblecycler]

All parts fail at some point ... it is more eye opening when it happens when either preparing to go out or actually out.

I am glad you are okay.

How long have you had the post? Where was the saddle positioned when it failed? I typically try to purchase a post that mounts to the center of the saddle rails with the thought (no scientific evidence) that it lessens stress on the saddle and post.

[mike p]

Thomson makes a great seatpost!! One of the best. I don't use them because I like a post with some setback. But any post can fail. You can go online and find everything from DA to Thomson to reynolds broken. Dosen't make them a bad post. What makes them bad are the numbers that fail. If you see hundreds or thousands fail I'd stay away.

Mike

[Lurch]

Thomson's customer service is pretty phenomenal. I bet they'll warranty, if for no other reason then to get the picture off the forums and prevent a rash of OMG the seatposts are unsafe threads. :)

FWIW, I outweigh you by an easy 80 lbs, and I abuse the hell out of 4 different Thomson posts, road, cross, and MTB, without so much as a squeak. They're highly recommended in the clyde community, so they're fatty approved.

Bzzzzt, claim over! ;)

[slowandsteady]

http://www.lhthomson.com/gallery/Fatman1280.jpg


...the scary thing is I think that guy blew past me today! Igotta get back in the saddle and put some miles in :crap:

[maunahaole]

lots of info here (http://cozybeehive.blogspot.com/2009/04/broken-thomson-seatposts-overtightening.html)

[nahtnoj]

Thomson is an amazing company.

I crashed my MTB once and put a huge dent in the seat post. I wrote them asking if the post was safe to ride or if I should purchase a new one. They said, "yep, pretty big dent, send that back to us". I had a new post in three days. Admitted straight up it was the result of crash damage. No expectation other than hoping to get an opinion.

Pretty sure they will give you a new post. I'm going to go now and loosen the seat clamp bolts on all of mine...you (and probably a lot of other people) over-torqued that.

[benb]

You know I think it might just be worth it to try a different design..

I think there stuff really isn't as bulletproof as they claim.

The problem with them wanting everything torqued correctly is:

- It's something that sometimes needs to be adjusted frequently or perhaps in a side of the road situation

- In my experience their clamp design creaks like a mofo and I was constantly having to take it apart, clean it, grease, and reassemble, increasing the chance it would get torqued incorrectly

- Positioning of the screws means they get hit with dirt, grit, and water

- Not particularly compatible with the widest range of saddles - with so many of today's flexible saddles it's difficult to get the saddle lined up level side-to-side on a Thomson IMO.

I actually like Specialized's current design better.. still has infinite adjustment, only has one bolt (larger and handles a higher torque), keeps the bolt to the side so it doesn't get sprayed with road grit, etc.. And the way it clamps from the side eliminates crooked saddles, etc.. We will see how long the specialized lasts of course..

I had one of their stems fail, it got sent back and they agreed I did not over-tighten it, and they did replace it.. but their service sucked.. it took them 4 months to handle my warranty claim, basically till the end of the season.

Good stuff but I'm skeptical they're so much better then the other options out there.

[Charles M]

I think there stuff really isn't as bulletproof as they claim.
.


I think it's a general public claim / assumption more than Thompson.


But...


This is the fourth one of these post failures I've seen and Thompson have had enough of them that it needed addressing.


You can't fault a company for wanting people to follow torque spec's. That's reasonable.


I think people just assume "it's metal, so it has to be tough.

And just like anything else that's very thin, it can break...

Thompson take pretty good care of their failures...

[zap]

Not a seatpost but last month I did find a crack in our 2 year old X4 stem installed on our tandem. Damn glad I found it as I suspect one or two more out of saddle sprints would have caused a not so nice accident.

All bolts were torqued 20% below max spec.

Returned the cracked stem to Thomson and they promptly sent me another stem. I will use this stem for 1 year (inspected often) then I will put it in the recycle bin.

Our new to us travel tandem has forged stems. ;)