Did I crack my carbon seatpost?
Hello everyone it's my first post.
I bought a giant fastroad slr 2, fork and seatpoat are composite.
I have a torque wrench. Its written max 13nm on the seatpost clamp.
I only chose to go up to 11.5nm to be in the safe side. To my surprise I wanted to change the hight after the ride and when I got the seat post I found a vertical straight line from the point of clamping till the end of the seatpost tube. It wasn't there before.
I was riding on a littlebit rough terrain at some point. Can anyone help me out? Is it a crack or not? Should I ride on it or buy a replacement?. It starts from 60 where I clamped and it goes down all the way in a straight line.
I bought a giant fastroad slr 2, fork and seatpoat are composite.
I have a torque wrench. Its written max 13nm on the seatpost clamp.
I only chose to go up to 11.5nm to be in the safe side. To my surprise I wanted to change the hight after the ride and when I got the seat post I found a vertical straight line from the point of clamping till the end of the seatpost tube. It wasn't there before.
I was riding on a littlebit rough terrain at some point. Can anyone help me out? Is it a crack or not? Should I ride on it or buy a replacement?. It starts from 60 where I clamped and it goes down all the way in a straight line.
0
Comments
-
it just looks like a scratch that you might get if there were a very small bit of grit in there. but ion course its hard to see from the pic.0
-
13nm seems a very high torque setting to be clamping a carbon seatpost to.
Are you sure it's not the number for the saddle clamp?0 -
Joe Totale wrote:13nm seems a very high torque setting to be clamping a carbon seatpost to.
Are you sure it's not the number for the saddle clamp?
....or not!?
See page 36 onwards for torques:
https://dstqaa92re5c4.cloudfront.net/Ma ... ike_EN.pdf
Carbon frames is 7.8-11.7 Nm but others go up to 21Nm!!Sometimes. Maybe. Possibly.
0 -
Yes I am sure at least that's what is written, the frame is aluminum but the seatpost and fork are carbonfiber, more pics
0 -
Other than the faint line down it (which looks like a minor scratch, not a crack) - do you have any particular reason to believe that the post is actually cracked?0
-
Imposter wrote:Other than the faint line down it (which looks like a minor scratch, not a crack) - do you have any particular reason to believe that the post is actually cracked?
Well I am doubting that maybe my torque wrench was out of calibration thus putting more force and on the inside I see a hairline scratch not sure if it is scratch or crack as well
0 -
Got to say, that appears to be an aluminium post - not carbon. If so, I'd just stick it back in the bike and carry on riding..0
-
Std descriptions for the SLR 2 say carbon fork - nothing about the seatpost - so unless it's been upgraded?
Your last pic does look like an alloy seatpost ...0 -
looks more like a surface scratch, and alloy
bear in mind that the maximum torque is a limit, not a recommendationMosman wrote:...
I only chose to go up to 11.5nm to be in the safe side.
...
you need only tighten enough to prevent the post slipping, and applying some cf assembly compound to the clamped area will typically reduce the torque required to do that (works just as well on an alloy post as a cf one)my bike - faster than god's and twice as shiny0 -
Imposter wrote:Got to say, that appears to be an aluminium post - not carbon. If so, I'd just stick it back in the bike and carry on riding..
It's says composite on the website and I am sure it isn't aluminum.
Well I was thinking the same, keep riding until something arises and keep checking for any changes in the seatpost!0 -
sungod wrote:looks more like a surface scratch, and alloy
bear in mind that the maximum torque is a limit, not a recommendationMosman wrote:...
I only chose to go up to 11.5nm to be in the safe side.
...
you need only tighten enough to prevent the post slipping, and applying some cf assembly compound to the clamped area will typically reduce the torque required to do that (works just as well on an alloy post as a cf one)
I am learning the hard way :roll:0 -
All the pics you've posted here give the appearance of a shot-peened alu post, not carbon. Although the spec does seem to suggest otherwise. Either way, I don't think it's cracked..0
-
It's easy to tell if it's alu or carbon, have a look when you get home.
Giant do have a habit of making mistakes when it comes to their specs, for example the Contend SL 2 has an alloy D Fuse seatpost despite the spec stating it's carbon.0 -
Joe Totale wrote:It's easy to tell if it's alu or carbon, have a look when you get home.
Giant do have a habit of making mistakes when it comes to their specs, for example the Contend SL 2 has an alloy D Fuse seatpost despite the spec stating it's carbon.
how can test if it's alu or composite?0 -
Tap it - aluminium will have a definite metallic 'tink' and carbon a hollow 'thunk' - probably ...Mosman wrote:Joe Totale wrote:It's easy to tell if it's alu or carbon, have a look when you get home.
Giant do have a habit of making mistakes when it comes to their specs, for example the Contend SL 2 has an alloy D Fuse seatpost despite the spec stating it's carbon.
how can test if it's alu or composite?
The end pic you took is very shiny too - that looks metal - carbon won't look like that.0 -
Slowbike wrote:
Tap it - aluminium will have a definite metallic 'tink' and carbon a hollow 'thunk' - probably ...Mosman wrote:Joe Totale wrote:It's easy to tell if it's alu or carbon, have a look when you get home.
Giant do have a habit of making mistakes when it comes to their specs, for example the Contend SL 2 has an alloy D Fuse seatpost despite the spec stating it's carbon.
how can test if it's alu or composite?
The end pic you took is very shiny too - that looks metal - carbon won't look like that.
I will check this out.
Last pic is just my flash light overexposed area but not real color.0 -
thats ali. its silver and bobbly and shot peened and painted and ali.
if you want to be 100% sure get a blade and scratch it. if its metal it will be silver, its its carbon it will be black. obviously do this somewhere discreet.
either way, its fine to ride.Postby team47b » Sun Jun 28, 2015 11:53 am
De Sisti wrote:
This is one of the silliest threads I've come across.
Recognition at last Matthew, well done!, a justified honoursmithy21 wrote:
He's right you know.0 -
More sanity by the mf’sMatthewfalle wrote:thats ali. its silver and bobbly and shot peened and painted and ali.
if you want to be 100% sure get a blade and scratch it. if its metal it will be silver, its its carbon it will be black. obviously do this somewhere discreet.
either way, its fine to ride.
Op wot e sed is right0 -
Matthewfalle wrote:thats ali. its silver and bobbly and shot peened and painted and ali.
if you want to be 100% sure get a blade and scratch it. if its metal it will be silver, its its carbon it will be black. obviously do this somewhere discreet.
either way, its fine to ride.
Thank you so much. That makes sense. When I get home I will surely do that. I hope I see silver when I do that ... 0 -
I did a scratch with a knife tip and silver showed under
Now I can ride in peace again. Big thank you to everyone who contributed!
0 -
You've been diddled out of a carbon post, take it back to the store and get it swapped.
================
2020 Voodoo Marasa
2017 Cube Attain GTC Pro Disc 2016
2016 Voodoo Wazoo0
