Quote Originally Posted by laura* View Post
My impression is that the Zertz are there to reduce high frequency vibrations - i.e. stuff you'd perceive as buzzing.

They are not an alternate to suspension components. They won't do anything to smooth out a bumpy road.

I think laura* is right. I don't know if this is helpful but when looking for a road bike earlier in the year, I test rode a Scott, a Fuji, the Specialized Dolce Sport, a Trek and one other, all on the same day. The Specialized was the most confortable and with the least road buzz despite the fact that the Trek I tested had a carbon seatpost and forks while the Specialized only had carbon forks and an aluminium seatpost. As I have only ridden steel bikes for the last 5-6 years, the difference with aluminium seems quite pronounced to me.

The Specialized may have felt more comfortable partly due to the Zertz inserts, which I think are made from a kind of plastic. But pll is right about geometry and tyres. The Specialized was designed to be comfortable over long distances and had 25mm tyres as opposed to the 23mm on the others. Like she said, do test ride both. While the Specialized was more comfortable, it also felt less lively which in my view weighed against it despite having the best looks too.