Joy of flex
A compliant seatpost has the potential to be an easy upgrade for more comfort
Everyone wants more comfort, but adding vertical flex into a rigid frame is a difficult thing to do without compromising other areas like lateral stiffness, weight or aerodynamics.
A stiff bike is a fast bike, so when it comes to adding in comfort, manufacturers and riders are obliged to look at areas beyond the frame, such as tyres or special suspension devices. Or seatposts.
Being a simple cantilevered tube, a seatpost can bend in a way that potentially improves ride quality without affecting the rest of the frame. What’s more, a seatpost is a simple upgrade to make. Even the most mechanically averse cyclist should be able to fit a new post without requiring a trip to their local bike shop. As such, several brands offer seatposts that are specifically designed to boost compliance, although each one goes about achieving the desired effect via different means.
Under the surface
Considering its conventional looks, you’d be forgiven for thinking Ritchey’s WCS Carbon Link Flexlogic wasn’t anything other than a regular seatpost, but as Ritchey’s Jeff Lockwood explains, the seatpost’s features are more than skin deep.
‘The post’s carbon layup is 15% more compliant than what we use for other posts,’ he says. ‘It offers a nice amount of compliance without using heavy gimmicks or exaggerated technologies. Go too far in a seatpost and efficiency and power can start to be affected.
‘ We opt to mute road vibrations, our thinking being people can ride longer and happier before they start to experience fatigue or discomfort.’
Canyon’s S14 VCLS 2.0 CF seatpost is altogether more conspicuous. ‘The design is basically a leaf spring concept with two carbon pieces anchored at the bottom and a floating saddle clamp at the top,’ says Canyon’s Matt Leake.
‘We think the advantage over more conventional designs is more deflection and more consistent saddle tilt in that movement. If your saddle angle is constantly moving around over rough terrain, that can cause discomfort over time. More conventional posts do tend to be lighter though, and occasionally our post should be removed, cleaned between the springs and have carbon paste reapplied to avoid any creaking – although this is an issue that can
occur with any standard carbon post in a carbon frame.’
Cane Creek takes a different path again, its eesilk post using a linkage design just under the seatpost head.
‘Our patented parallelogram suspension uses the bike’s seat tube angle and the damped spring forces of an elastomer to suspend the rider,’ says brand manager Sam Anderson. ‘The elastomer’s firmness can be adjusted for rider weight, and the “arch” created by the direction of the parallelogram travel maintains the same distance from the saddle to the pedals. This is a huge advantage to something like a telescoping design. That can reduce the effective saddle height, which in turn will reduce rider watt output.’
No more niche?
Cannondale’s HG Save seatpost moves back into the realms of the inconspicuous, with only subtle carbon shaping visible at the top of the post. Product manager Sam Ebert says the tube shaping and layup combine to create the best balance of weight, compliance and compatibility.
On the topic of compatibility, as well as offering the post in a universal 27.2mm diameter, Cannondale offers the post in a 25.4mm diameter to fit its Synapse endurance bike. Seatposts are increasingly being designed as part of a frameset ‘module’, so could this trend towards proprietary designs make thirdparty comfort-boosting posts obsolete?
Ebert says it depends on the category, but sees potential in the gravel sector: ‘Gravel bikes invite riders to tailor them to their varying needs and aspirations.’
Cane Creek’s Anderson and Ritchey’s Lockwood continue to see their value on the road. ‘If bike manufacturers continue to build stiff frames that need to compensate for compliance somewhere, aftermarket posts such as ours will continue to be sought after,’ says Lockwood.
As an employee of one of the world’s biggest bike brands, Canyon’s Leake takes a holistic view.
‘I think there will always be a balance between proprietary systems at the premium end and conventional round seatposts for more value-focussed propositions. The VCLS 2.0 concept from us isn’t going anywhere any time soon,’ he says.
So with comfort-boosting seatposts here to stay, you may want to consider making the investment. Your behind might be up front in thanking you for it.
‘If bike manufacturers continue to build stiff frames that need to compensate for compliance somewhere, aftermarket posts will continue to be sought after’