- It broke "clean off"
Spike is not perhaps the best name for a seatpost in retrospect.Posted 6 years ago
I’ve bent a few in my time and snapped one, but it was a cheapo and luckily no damage to me!
Im prob about 17st in my riding kit and don’t tend to skimp on seatposts. Both bikes have Thomson posts now and they are good. Not perhaps the lightest but they last.
(I’ve bent control tech, x lite cheese, kalloy) The only ones that have lastetd were a proper an original hardcore Syncros post and 2 x Thomsons.billybouldersMember
Hmm That is a bit worrying – got one of those Ragley seatposts, will have to check it thoroughly when I get home.
Seems Ragley are having more and more problems, no wonder Brant stopped telling us it was “his brand” and jumped ship! Such a shame too ‘cos the bikes ride brilliantly (IMO)Posted 6 years ago
By the looks of it, it’s seen some damage caused by it slipping under load with the clamp tightened, and I’d wager that’s what initiated the crack that then propagated round the circumference.
Might have been slightly undertightened, might have been a little undersized for the frame meaning you’d have to tighten the clamp hard but that the tube wasn’t gripping the post properly. Might have been something slightly different. But I’m guessing you’ve noticed at slipping at some point – any thoughts?Posted 6 years ago
My seatpost that is, clean in half right at the top of the seat tube. It happened at the end of the descent from the top of Curbar Edge, the first time I have been there and as such I was going slowly looking for the gate to join the lane. So the question I suppose is “Did I feel lucky?” (Punk) well, I did, because if it had snapped halfway down the descent it might have made things interesting for the wrong reasons.Posted 6 years ago
I have never in my 20 years of mtb’ing snapped a seatpost clean in half. Do I feel proud or disappointed? Is it me or…
Seat post was a Ragley Spike 27.2 x 400mm, with loads in the frame, that being a Cotic Soul (natch, see username)
Could quite possibly be slightly undersized. And obviously made of cheese.
I wouldn’t be so damning of it. A poor fit between the post and frame will cause a massive stress riser at the clamping point, and slipping under load may cause a significant bit of wear. The failure’s not necessarily an issue with the material.Posted 6 years agotoys19Member
The failure’s not necessarily an issue with the material.
Unless it had massive inclusions or somesuch, seems unlikely though. I used to spend hours looking at fracture surfaces in the electron microscope trying to identify exactly what intiates these types of failures.Posted 6 years ago
“Unless it had massive inclusions or somesuch, seems unlikely though.“
Also (although this is very hard to be confident of, given the not-ideal quality of the photo) the fracture surface looks reasonably fresh all the way around, which would suggest that it’s propagated quite quickly under relatively high stress – a scenario which would be better explained by the stress concentrations you’d get from a poor fit than by the more even stress distribution you’d see in an accurately-fitting post with an inclusion.Posted 6 years ago
I’ve previously owned a Mk1 Soul, and that was with a Salsa shaft seatpost. It needed an initial tweak of tightness of the seat q/r after the first ride but that was all. However this time on a newer Soul, the seatpost needed several tightening tweaks, which I thought was probably due to the gloss surface of the post. I did have a 31.6 spike in a Helius which showed no signs of slippage from the get go. I also examined the fractured area to see if I could find a dark spot, to suggest that a crack was present for some time, there isn’t, it just failed catastrophically.Posted 6 years ago
Okay so I wasn’t on Curbar Edge, I haven’t been there before and after checking the map I was on Baslow Edge, just got to the bottom, slowed down looking for the gate to the lane sat down then ‘pink’ (luckily not followed by a brown) The Thomson layback post fits nicely though, had to back off the q/r which may suggest the spike was undersized?StonerSubscriber
The Thomson layback post fits nicely though, had to back off the q/r which may suggest the spike was undersized?
if you have access to a vernier, that might clear things up.
Ive found quite a bit of variation over 3 or 4 27.2mm posts in the past.
As it happens I have a new set of verniers in the post and 6 or 7 different brands of 27.2mm post. Will check them and the seat tubes out and post the results.Posted 6 years agoivantateMember
My spike slipped when in my blue pig frame, to the point the Ragley seat clamp broke halfway through a ride when it was tight enough to stop it slipping. No problems with the Thompson in it now. The spike is fitted to my five and is a really flexible post.Posted 6 years ago
Maybe I shouldn’t use it any more!
The topic ‘It broke "clean off"’ is closed to new replies.