Stock Thorn Sherpa seat bolt breaks after 7000 miles

[triaesthete]

I've just had a look at the bolts on the Thorn seat pins in my garage and I notice that the heads on them have no coded tensile strength markings.

Very curious
Ian

[Danneaux]

I've just had a look at the bolts on the Thorn seat pins in my garage and I notice that the heads on them have no coded tensile strength markings.

Well, Ian, that was enough to get me up off my chair and out to where the Nomad is parked by the fireplace for a quick look-see with my LED headlight (it's 23:36 here and dark of night). The bolt head on my Thorn long-layback seatpost clamp (marked "Zoom 3D") is also unmarked. For what it is worth, I have several other seatposts in a variety of other brands over the years that also use bolts with no coded tensile strength, but they've never been a problem.

Very curious

Indeed!

All the best,

Dan. (...who is always curious himself about such things!)

[triaesthete]

Hi Dan
practical detective work on your part. I expect getting a bolt with a head marked 8.8 or higher would be good anti failure insurance.
Cheers
Ian

[SuffolkPunch]

Okay...Thanks to everyone for such helpful and varied advice!

I am now the proud owner of the Thomson Elite layback seatpost! Trivia alert: Who knew it came in its own tasteful posing pouch - see attached jpg? Plus to fit it properly, I also got a torque wrench and a set of hexagonal bits (why are hex bits so hard to find compared to allen keys??).

Thanks also to Thorn Cycles who immediately sent me a free replacement Thorn seatpost.

Martin