FSA SL-240 Carbon Pro CSI seat post review

Tough & comfortable carbon/aluminium post

Our rating 
4.5 out of 5 star rating 4.5
GBP £50.00 RRP
FSA SL-240 Carbon Pro CSI seat post

Our review

New technology makes this a comfortable but durable post
Skip to view product specifications

This new 228g post sporting FSA’s ‘Carbon Structural Integration’ technology has proved impressively comfortable, creak-free and durable on our hardtail testbed. It’s even stood up to a proper beating through rock gardens and seated bouldery singletrack descents.


 Despite our general mistrust of single-bolt serrated cradle seat clamps, we’re pleased to say that the one used here – shared with the SL seat post – has been fine.

Carbon Structural Integration is FSA’s new technique of carbon ‘shrink wrapping’ alloy components using a high-pressure sock mould. 

By wrapping the carbon under high pressure, the fibre actually provides a genuine structural advantage rather than just a cosmetic finish. FSA claim that this not only improves basic strength, but also improves its shock-absorbing qualities and reduces the potentially brittle nature of either carbon or alloy alone.

This makes it a perfect construction technique for something that takes a lot of flex and impact loading, such as stems (OS-99), handlebars (XC-220) and this  seat post. 


The final bonus is that it’s also cheaper than a complete carbon shaft seat post, even though the performance is actually considerably better than many of them.

Product Specifications


Name SL-240 Carbon Pro CSI seat post
Brand FSA

Weight (g) 228
Single Bolt-Head Yes
Material Alloy Carbon Fibre