bonsaibilly
Guest
I'm sorry, I was replying to the question from Heisenberg71.
I'm not sure how the zerts inserts work, I'm sure you can find an explanation from Specialized online. What I can say is that it test road both a Specialized Tarmac and Roubaix at the time of purchase, the carbon lay up was the same and apart from the longer head tube the geometry very similar. Both bikes were excellent but the Roubaix was a noticeably smoother ride which can only be due to the Zerts inserts. There will be no advantage in performance but a definite advantage in comfort.
Okay, that's odd because I've just read the Specialized technical notes for the Roubaix and Tarmac which say that they are made of completely different lay-ups (of the same base materials) and this combined with the wheelbase length and the head angle account for the change in ride quality. BB