With all due respect incorrect fitting and misuse is the main reason for failures, I've been riding CF posts for over 10 years and I've just trimmed down to 100kg (220lb). I've ridden Campagnolo Chorus Carbon, USE Alien (on my audax bike) as per your vid and mostly a Specialized with zertz dampener on my daily commute/utility bike since 2007 and around 50,000 miles.
My advice to prevent over-tightening, use fibergrip, it keeps the seatpost in place very well, and you only need the minimal amount of torque to keep it in place. To be fair, alloy seatposts are almost bomb proof, but the seatpost in this vid looked very thin down the tube. I ride an FSA k force light, and it's twice as thick as the USE, but still, choose your seatposts wisely my friends
Can u mention how it was to begin with, in comparison. Was it better, less vibrations, how much suspension effect does carbon seat post have compared to aluminium..
I am looking to got to carbon fiber strictly to lighten up my Mt. bike a bit. In the past I have used carbon handlebars with no issues(Easton Monkey lites). My main concern with the CF seat post is how well it will play nice with the aluminium frame. My frame also has the crimping sleeve for the seat post and just the nature of the metal flexing around the carbon looks like it could cause damage. Maybe using a shim like pluming tape or silicone tape would help to protect a CF seat post to pare with an aluminium frame. I think the weight savings for bars and seat post could be up to half a pound which makes a difference on climbing with my 29er.
Well, it seems that a carbon fiber seat-post is more likely to fail from tightening (not necessarily over-tightening) than the metallic ones. I wonder if a thin metal sleeve in the load area would be the answer meaning that the seat post diameter would have to be that much smaller to accommodate for it. On a road bike, you figure there would not be that much horizontal stresses compared to a mountain bike.
Can't a close fitting thin wall stainless tube or relatively thick wall alum. tube be epoxied within, with holes for easy epoxy application and wiggling to distribute evenly..
USE Alien seatpost was a stupid light piece of kit 8 years ago when they were current. Aside from the cyclops head being a pain to set they were also notoriously fragile and susceptible to cracking when overtightened.Carbon posts made today are much more tolerant. Also, the cracking had nothing to do with rider weight.
Carbon bike parts like seatposts, handlebars, etc. have tolerance limits printed on them or the clamping parts like a handlebar stem. This is where a torque spanner comes into play. Set the spanner for the proper torque setting, and don't tighten it anymore. Pick up a relatively inexpensive spanner from lots of reputable sites, and save your carbon parts. You'd often be surprised how little torque is required to hold carbon parts.
I used the Easton EC90 carbon seatpost on my Scalpel and it didn't last a month before it snapped like a toothpick. I only weighed 175. Carbon is a crap material and it's not a question of if it will fail, but when. Buy a titanium seatpost and be done with it.
Looks like you over tightened there chief
If you tighten the bolts too much that actually makes the carbon fragile. There are also 200lbs riders without issue with the carbon seat-posts...
Over tightening dude.
With all due respect incorrect fitting and misuse is the main reason for failures, I've been riding CF posts for over 10 years and I've just trimmed down to 100kg (220lb). I've ridden Campagnolo Chorus Carbon, USE Alien (on my audax bike) as per your vid and mostly a Specialized with zertz dampener on my daily commute/utility bike since 2007 and around 50,000 miles.
My advice to prevent over-tightening, use fibergrip, it keeps the seatpost in place very well, and you only need the minimal amount of torque to keep it in place. To be fair, alloy seatposts are almost bomb proof, but the seatpost in this vid looked very thin down the tube. I ride an FSA k force light, and it's twice as thick as the USE, but still, choose your seatposts wisely my friends
Can u mention how it was to begin with, in comparison. Was it better, less vibrations, how much suspension effect does carbon seat post have compared to aluminium..
does the carbon creak while the crack expands?
I think the best course if action is to check seat tube for out of round and any burrs or defects on inside
Did someone mention that might be from overtightening yet?
Thanks for the info 👍
I am looking to got to carbon fiber strictly to lighten up my Mt. bike a bit. In the past I have used carbon handlebars with no issues(Easton Monkey lites). My main concern with the CF seat post is how well it will play nice with the aluminium frame. My frame also has the crimping sleeve for the seat post and just the nature of the metal flexing around the carbon looks like it could cause damage. Maybe using a shim like pluming tape or silicone tape would help to protect a CF seat post to pare with an aluminium frame. I think the weight savings for bars and seat post could be up to half a pound which makes a difference on climbing with my 29er.
That's what happens when you over-tighten the clamp
Well, it seems that a carbon fiber seat-post is more likely to fail from tightening (not necessarily over-tightening) than the metallic ones. I wonder if a thin metal sleeve in the load area would be the answer meaning that the seat post diameter would have to be that much smaller to accommodate for it. On a road bike, you figure there would not be that much horizontal stresses compared to a mountain bike.
Get a better quality seat post and tighten to 5nm. Or use your aluminum seat post.
ENVE 31.6 post and I weigh 130lb. Should be OK? I'll get some fiber grip.
Can't a close fitting thin wall stainless tube or relatively thick wall alum. tube be epoxied within, with holes for easy epoxy application and wiggling to distribute evenly..
they're ALL from "China" baby! (P.S. that is an over tighten fracture based on the vertical crack.)
USE Alien seatpost was a stupid light piece of kit 8 years ago when they were current. Aside from the cyclops head being a pain to set they were also notoriously fragile and susceptible to cracking when overtightened.Carbon posts made today are much more tolerant. Also, the cracking had nothing to do with rider weight.
Carbon bike parts like seatposts, handlebars, etc. have tolerance limits printed on them or the clamping parts like a handlebar stem. This is where a torque spanner comes into play. Set the spanner for the proper torque setting, and don't tighten it anymore. Pick up a relatively inexpensive spanner from lots of reputable sites, and save your carbon parts. You'd often be surprised how little torque is required to hold carbon parts.
I used the Easton EC90 carbon seatpost on my Scalpel and it didn't last a month before it snapped like a toothpick. I only weighed 175. Carbon is a crap material and it's not a question of if it will fail, but when. Buy a titanium seatpost and be done with it.