Cane Creek Thudbuster ST G4 suspension seatpost

The Cane Creek Thudbuster ST G4 is the fourth generation of the iconic short travel suspension seatpost (which also happens to be one of my favourite suspension posts of all time). This time round it's marketed at e-bike audiences and commuting, with 50mm of travel and a comprehensive mechanical makeover. It's also claimed suitable for riders up to 150kg.

Specification

This incarnation of the ST (short travel) Thudbuster still employs the parallel linkage design, using hard anodised axles and flanged PTFE bushings for slick, low-maintenance service.

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This time round, the elastomers are a tool-free press fit, so relatively easily switched to suit a softer or firmer action, depending on your weight and, possibly, where you ride. I say relatively, since the firmest stock model required very strong thumbs; the softer was very compliant.

Ours came with the medium fitted, which ultimately ticked all the boxes for me, but it's worth checking Cane Creek's guide and choosing what's suitable for you – not that they're difficult to exchange: simply press the inner elastomer until it pops out, then slot in your substitute. (Soft and hard are included in the box; extra soft and extra hard are available to order separately.)

Elastomers do like the occasional lick of rubber-friendly grease, too – think along the lines of Judy Butter, Green Oil Ecogrease or Muc Off Silicon Shine. Avoid old fashioned greases designed for classic cars and motorcycles; these, like PTFE greases, will do horrible things to modern elastomers. I speak from first-hand experience...

The previous G3 Thudbuster had 33mm of travel and was available in five diameters, 25.4, 27.2, 30.9, 31.6 and 33.9mm, but I wasn't surprised that the G4 now comes in only three – 27.2, 30.9 and 31.6mm – as things have become largely standardised. Shims are available separately.

Saddle clamp

The single-bolt saddle clamp design is intended to make alignment and adjustment easier – and it does. However, it seems a curious choice for a system designed to support heavier riders.

It's designed to accommodate both round and oval rails – just slacken the cradle with a 5mm hex key, click your saddle into place, then wind it up to 16Nm with a torque wrench.

The science behind the design keeps it in the direct path of the rear wheel. As a bump shoves the bike's rear wheel, the Thudbuster reacts downward and rearward, theoretically absorbing force at the same rate. Hence zero saddle movement and why it doesn't feel like a pogo stick.

The concept does rely on at least 100mm of exposed seatpost, which shouldn't be an issue for most, but is something to consider if the post is used by riders of different heights, like tandem stokers. (It's also something to bear in mind when fitting luggage – some larger saddle/seatpacks might not fit.)

Before installing the post, treat it to a light coating of compatible grease (metal frames) or gripper paste for carbon frames.

Performance

From the outset, the linkage design offers a very progressive, subtle movement, which damps out smaller ripples without impeding a decent cadence. My fixed gear winter/training bike could never be described as harsh but there was a discernible difference between a rigid post, even a titanium one, and the Thudbuster over the same sections.

Switching to 38mm gravel tyres and meandering along dirt roads, the linkage compressed progressively, absorbing the shock without any weird rebound or annoying bob. This was also true when alternating between sitting and climbing.

Ultimately, I felt a whole heap fresher than usual, after 50-mile mixed terrain loops. This bodes well for the latest generation of e-bikes, which seem to be stiffer in order to support increasingly powerful engines and not handle like a blancmange.

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I've experimented with switching to a softer elastomer off-road and benefited from the increased sensitivity; the softer setting is too responsive on metalled roads and smoother tracks, but the simplified system means road/trailside switching is a practical possibility.

One thing I was surprised to discover was the need to snug the cradle bolt down each time after three 25-mile road outings. Most of us will appreciate that things settle a bit during the first few rides, and thankfully this hasn't proven an issue in the subsequent weeks, but I'm only 70-odd kilos... I'm not entirely sure it's optimal for riders exceeding 100kg.

How does it compare?

Aside from running the original Thudbuster ST for a few years, I've also done a few hundred miles on the Redshift Shockstop Suspension post. The latter feels a little plusher than the Thudbuster ST G4, though the Thudbuster has 50mm of active suspension travel (the Redshift 35mm) and without any loss of manners.

The Redshift is a little more enclosed in its design, which may be a consideration if you're running a gravel bike through the depths of winter, but aside from the odd cursory wipe-down, there's been no call for more involved maintenance with the Thudbuster through a dry and dusty testing period.

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The Redshift is also £229.99, so although £169 is a sizeable investment for a seatpost, the Thudbuster is competitive in its market. Both weigh in at 545g apiece.

If your riding is predominantly on the road and you want some compliance without the heft or complication, something like Specialized's CQ-R Carbon Seatpost might be a better option, but it's also more expensive at £185 rrp.

Summary

The Thudbuster ST G4 should satisfy those looking for some sophisticated compliance without breaking the bank. E-bike and cargo bike riders, especially those riding over longer distances, arguably have most to gain, though it's still a very good bet for cross/adventure-biased riding, not forgetting tandem stokers.

Verdict

Iconic suspension post updated with tangible benefits, save perhaps for the cradle