Cane Creek’s Thudbuster seatpost uses a unique design that gives it the smoothest, smartest suspension performance by far. You will pay extra pounds for it in both wallet and weight senses though.
By using two parallelogram linkages rather than a telescopic shaft, the Thudbuster moves down and backwards. This mimics your natural body movement if you were stood up absorbing a bump.
As well as making the motion feel natural, this also dramatically reduces the change in pelvis-to-pedal distance compared to a telescopic post, so pedalling rhythm is less affected. It also lets the bike rise up and forwards underneath you over bumps, and there’s no shearing stiction either.
The feel of the suspension action was initially pretty weird – akin to having a super-soft rear tyre – and it requires you to accommodate a constantly shifting bar/saddle distance, but we quickly adapted to it, particularly once the super-plush three inches of travel started soaking up the trail.
Two changeable density elastomers (more extreme aftermarket tunes are available) squeezed between the link as the spring medium mean easy spring-rate tuning.
Inevitably there are downsides. The most obvious is its hefty weight, which isn’t far off the difference between most hardtails and similar full-suspension bikes. The backwards/downwards motion feels weird at ﬁrst too.
The seatclamp is a bit of a fiddle. A 3mm hex bolt and a grooved thumbwheel deal with micro-adjusting the saddle angle, but we baulked at putting the usual amount of torque onto a bolt so small and soft.
Keep it regularly cleaned and serviced though (and maybe add the protective neoprene Crudbuster boot for £13) and it’ll stay smoother longer than any telescopic post. Once you’ve got used to the feel of the action and the smoothness it adds to your ride you won’t complain about the relatively high price tag or weight.