# Carbon steerer groove



## Oldteen (Sep 7, 2005)

I have an 07 Tarmac Expert with stock carbon steerer fork. Less than 1k mi with no crashes. On the road the other day (somewhat rough chip-n-seal pavement- no pothole hit) the stem slipped just a little (5 degrees or so). Stopped to check it on roadside & it seemed OK. Road home slow. Pulled the stem (stock Pro Road multi position). The carbon steerer has shallow but distinct grooves into the resin- probably from the stem shim (used with Spec mulit-position stems). NO cracks are visible. Stem was orginal install from a trusted LBS.
Is this marking normal with the multiposition stems & carbon steerers?


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## Oldteen (Sep 7, 2005)

FU-
LBS experienced mechanic examined steerer & did not see any cracks either. He felt markings were normal- nothing to worry about. 
Did not mean to waste his time (he refused any $$ to re-install my stem), but better safe than sorry. 
Got to talking with him a bit about steerers. He claimed he had seen more "catastrophic" failures from AL steerer tubes on carbon forks than on carbon steerer forks. AL separating from carbon at the joint is disaster, while all carbon may split (bamboo-like failure) which might allow rider some residual control of bar/stem. Not sure I buy that logic, but it would be interesting to see any stats on the subject.


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