RSS Feed

FSA K-Force Light SB25 Seatpost

Posted on
Seatpost In Action

Graphic courtesy of Road Bike Review

I have written a few posts about my Alchemy Eros.  Starting with A Bicycle for the Cognoscenti Adventure, followed by My New Best Bike:  the Alchemy Eros, and 4,000 km / 2,500 mi Update:  Alchemy Eros.

A common theme in the two later posts is that the trade-off for a stiff and sharp handling titanium frame is a ride that is sometimes jarring.  I have owned, and still own in the form of a Ritchey Break-Away Road Ti / Carbon, Ti bicycles that are more comfortable.

I lived with the tradeoff between frame stiffness and comfort until I read an online article in VeloNews titled Getting the Most From Your Post.  First published in June 2012, the article is somewhat dated, but still relevant.  The article attempted to determine the role the seatpost plays in rider comfort.

In its typically thorough fashion, VeloNews set out to answer this question by testing 14 seatposts of different materials, setback and design philosophy. At Boulder’s Microbac accredited test laboratory, they measured vibration damping over small bumps with an accelerometer, and they measured linear deflection (flex) under body weight in two dimensions.

The winner was the FSA K-Force Light SB (Setback).  VeloNews judged the FSA seatpost to be the best choice for long road rides.   The FSA seatpost has excellent vibration damping, which makes it noticeably more comfortable, especially on long rides, dirt roads, or concrete or asphalt with lots of small cracks and expansion joints.

The seatpost that came with my Eros is the Ritchey Comp Carbon.

Ritchey Carbon Comp

Photograph courtesy of Ritchey

This seatpost was not one of those tested, but three other Ritchey seatposts, the WCS Carbon SB, the WCS Aluminium SB, and the WCS Carbon Straight, are among those in the Velonews review.  The Ritchey seatposts came in sixth, tenth and last respectively.

The Comp Carbon sits at the lower end of Ritchey’s seatpost offerings.  I thus assume that it would score even lower than its siblings on the VeloNews test.

Eager to soften the ride of the Alchemy Eros, I bought an FSA K-Force Light.

FSA K-Force Light

Photograph courtesy of Full Speed Ahead

I have the version with the same 25mm of setback that my Ritchey Comp Carbon has.  For purely aesthetic reasons I opted for the black and grey graphics rather than the red and white.

VeloNews had discovered that a setback post will give you greater pedaling efficiency and more high-frequency vibration damping.  My usual routes don’t have big bumps, where the greater flex of a straight seatpost is an advantage.

I have ridden 370km / 230mi on the FSA K-Light.  The ride quality of my Eros has noticeably improved.  Even with 10psi more air pressure in each tire.  There is much more vibration damping now.  My Eros rides much more like I would expect a Ti frame to ride.  So my qualitative impression so far matches the quantitative findings at VeloNews.

I have a 240km / 149mi ride, split over two days, this weekend.  I am looking forward to a more comfortable long-distance ride than I have had before on the Alchemy Eros.

About alchemyrider

I left Malaysia in 2008 as a non-cyclist. I am back home now with two road bikes and all the paraphernalia that goes with being addicted to cycling.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: