I’m just curious to know you guy’s thoughts on this cause it’s bugging me not knowing what it is just picked up a 2013-2014 Santa Cruz v10c and it’s got this odd looking line down the centre top of the top tube just wondering what y’all think about this it’s in the direct centre of the frame so I just need some opinions on this.
![Image]()
![Image]()
Carbon crack or is it just a seam or imperfection
Luca H
1 - 20 of 37 Posts
I’m just curious to know you guy’s thoughts on this cause it’s bugging me not knowing what it is just picked up a 2013-2014 Santa Cruz v10c and it’s got this odd looking line down the centre top of the top tube just wondering what y’all think about this it’s in the direct centre of the frame so I just need some opinions on this.
![Image]()
![Image]()
Yea I can’t feel anything and I’ve done the coin test and sounds the same all the way along.
I’ve asked a few mates they think it is just part of the construction of the frame too which sounds about right Thankyou for the help with this really appreciated
Joined
·
18,913 Posts
I think it's a standard seam, but reach out to SC and get a final opinion.
I had a weird spot on an ENVE rim. Sent pics to ENVE and they said it's normal. Didn't feel right so I took it to my LBS and they did the tap test and you could tell immediately that something was wrong. Got it warranty replacement.
Joined
·
2,266 Posts
I have seen this imperfection on several santacruz bikes of this particular age range... really 14-18 or so. I've seen this most commonly on nomad 3's and og highertowers in my riding crew 3 in total, which seems like a lot but a lot of us owned either hightowers or nomads. I digress... I cannot recall what the explanation is but if memory serves, it's really an imperfection in the clear coat/finish which appears over time due to just the stress in the underlying carbon layups. Either way, in each and every time this has come up (3 in total out of may be 10-15 of the bikes of this generation) it has been warrantied by SC with a frame replacement.
Joined
·
185 Posts
Has someone clamped this frame in a bike stand? Seems like an obvious spot where this the top tube could have been clamped and crushed some.... (never clamp your carbon frame into a stand, use the seat post)
Joined
·
18,913 Posts
I having a bit of difficulty buying into this theory.
Joined
·
4,741 Posts
Actually it makes sense if you know how frames are moulded.
The inner layers of carbon are interleaved at the mould line, so there is no "seam" structurally. Sometimes the outer layer is seamed right at the mold line for cosmetics. Once the frame is sanded there is no evidence of where the mould line was, however that outer cosmetic butt seam is still there. Expansion and contraction and movement in the underlying interleaved layers can cause that cosmetic butt seam to project into the clear coat. Basically exactly how a glue joint in a wood table will eventually project through the finish no matter how smooth and perfect it was sanded.
I would not have guessed they would warranty it since it should be just cosmetic, but then it is a very expensive frame where cosmetics are part of the deal.
Joined
·
18,913 Posts
My cool reception is the suggestion of stress in the underlying carbon layups. Is this a suggestion of thermal expansion or modulus of elasticity type of issue?
My take is this is lt a resin seam from the two mold halves. I do not think it is the result of any instability or stresses in the carbon as a root cause.
My take is this is lt a resin seam from the two mold halves. I do not think it is the result of any instability or stresses in the carbon as a root cause.
Joined
·
4,741 Posts
It can't be resin flashing from the mould line, that gets sanded away and can't "reappear" later.
Joined
·
4,741 Posts
Yeah I thought that was the edge of a decal or something.
Joined
·
662 Posts
I have the same seam on my new Blur I picked up a month ago. If SC says it’s not normal let us know.
Joined
·
167 Posts
I've got the same line on my 22' Blur and contacted SC about it. They confirmed it is simply an artifact from the molding process.
I've since seen three other 22' Blurs and they ALL had it.
I've since seen three other 22' Blurs and they ALL had it.
I suspect this is right on. The structural carbon layers underneath are stiffer than the pretty carbon wrapper they put on the outside, and the difference in stiffness can result in slight relative motion between the layers and this sort of "crack".
Some companies are probably just better at hiding the seams.
Yea Thankyou for the help and I’m taking it in for a service at “For The Riders” today I’ll see what they say. but yea to me it seems like it could just be a seam in the building process of the frame
Joined
·
265 Posts
My 2020 Santa Cruz Chameleon has the same line down the center of the top tube and down tube. Looks normal
1 - 20 of 37 Posts
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
