stay on the saddle all the time
Ergon CF3 Pro carbon seatpost has a very unique two leafs construction. This allows a lot of flex from the seatpost itself. And you can really feel it even when pedaling on flat sections. For many, this is a huge disadvantage but for me it is not a problem and you can really get used to it. Especially when the advantages of having this kind of seatpost are so apparent.
The first thing you will notice while riding on Ergon CF3 Pro Carbon (or it’s Canyon VCLS 2.0 equivalent) is the somehow muted feeling of the road. As if you had a puncture. But after a few more meters on a more challenging ground, you will also notice that you don’t have to any more rise your butt to avoid bigger hits. You don’t need to do it because there are no more big hits. So you can stay seated almost all the time and focus on pedaling and finding the best route possible. This is a ground-breaking change that allows you to go faster for longer periods of time. Of course, the more exposed the seatpost the more flex you will get. Also, a variant with a 25 mm setback (as I have) will offer you more flex than no setback version.
But the question is how much more comfortable the flexing Ergon seatpost really is? To find out I tested it alongside a more traditional FSA K-Force carbon seatpost which is famous for mitigating road vibration even in zero setback version (that I have). Riding on FSA K-Force subjectively is noticeably worse than on Ergon CF3 Pro. You can no longer stay seated and you can definitely feel the bigger hits on your butt.
Yet to my surprise the objective measurements showed that with tires at 40 psi (higher pressure of the tires allows the rest of the bike, especially seatpost to show its flexing abilities) Ergon post was in the forest better only by 9%. On the fast gravel route, the difference was even less substantial – only 2,9% with 40 psi tire air pressure. When I lowered down the tire pressure to 20 psi the difference was bigger but still only 6,4%. Interestingly both times when tire air pressure was lowered the comfort improvement offered by Ergon flexing seatpost was bigger – it looks like it needs more travel to show it strengths (which tire with lower air pressure provided).
Is this mean that a pricey CF3 Pro carbon seatpost is not that great addition to your bike when you want to improve the overall comfort? Not exactly. The case is much more complicated than that. First, let’s check the Cervelo’s official chart describing what contributes to the overall ride quality at the rear of a drop bar bike (https://www.cervelo.com/en/ride-quality). It’s a tire. In the second place is saddle and only third is a seatpost. When you add other parts like shorts and frame (my bike is made from steel which adds a lot of comfort itself) you will notice that we can’t expect miracles from changing just the seatpost itself. Especially on my test bike where I also use a very comfortable Brooks C17 saddle (which according to Cervelo is more important to overall comfort than seatpost and for sure I will try to verify this in near future).
So can I recommend Ergon CF3 Pro carbon? Yes! Especially when your frame is not so forgiving (like stiff aluminum one). Just don’t expect miracles and still think of other factors that can contribute to the overall comfort – like lowering the tire air pressure.