Suspension Seatpost Shootout: Put Some Spring In Your Seat

PUT SOME SPRING IN YOUR SEAT

If you commute to work on a bike, ride long distances, or have less-than-stellar pavement to ride on, unless you have a full-suspension bike, your ride can be a pain in the you-know-what. With aluminum hardtails still one of the most frequently relied on for the majority of entry-level e-bike models, many e-bike commuters we’ve spoken to are still searching for a better balance in speed and comfort. 

Many commuter bikes come with a suspension fork with enough travel to ameliorate some of the shock to your hands, but that leaves you with a sore derrière from the saddle. One good solution for this is a suspension seatpost. It doesn’t add as much weight or complexity (or expense) as a full-suspension bike, but they can make a huge difference in your comfort on rides.

“We took all three on a ride that had bumps, busted pavement and even rutted off-road sections, and all three improved the quality of the ride.”

We’re looking at three of the top choices on the market: the Cane Creek Thudbuster, Redshift ShockStop and Kinekt 2.1. They all have very different designs but similar ideas on how to tame the bumps in the road. We took all three on a ride that had bumps, busted pavement and even rutted off-road sections, and all three improved the ride. 

THUDBUSTER ST

The Thudbuster ST uses a unique dual-elastomer system. See the insert in the middle? That’s removable to insert a firmer or softer option. The three dots in the insert show this as the medium.

 

The Thudbuster line of suspension posts have been around for over 20 years. Most of their models use elastomer springs instead of coil springs and the ST uses a big, square elastomer positioned in the middle of the parallelogram-shaped head with an innovative cut-out middle section for varying elastomer inserts that are set up for soft, medium and firm rides depending on rider weight and preference. There are extra-soft and extra-firm inserts available separately.

The post is available in three sizes—from 27.2mm to 31.6mm diameter with optional shims for
other sizes.

Saddle installation is different than most posts. We’d definitely suggest watching the video on Cane Creek’s website as we did, and we fully disassembled the seat-clamp system. The interface involves a hole through the top of the post with fittings for the rails and a male/female bolt that can take some work to thread together. Two hands are almost not enough. Once it’s going, however, it is actually easier to level the saddle. 

We didn’t care for the Thudbuster we rode years ago, as each bump force moved the saddle back significantly, making us feel like we were falling backwards. This new design feels far more linear. Of the three posts tested, the Thudbuster offered the least amount of damping. The soft insert was definitely better, but your mileage may vary depending on your weight and preference. 

Price: $169.99

www.canecreek.com

REDSHIFT SHOCKSTOP

The Redshift ShockStop has no externally visible springs, so preload must be adjusted with the seatpost fully out of the frame.

 

Redshift offers only one model, and it is only available in 350mm length and 27.2mm diameter, but with a variety of available shims to fit up to 31.8mm tubes. It will only fit round, not aero, tubes. 

It has a preload adjustment and comes with an extra spring to allow riders to make it firmer. That spring is inserted internally. They’ve made it very user-friendly, even printing some instructions on the spacer inside. To aid assembly, they have a well-done, 20-minute guide to installing and setting it up on their website. 

“We found this one to feel the most natural, making for a really plush ride, like having rear suspension.”

The factory setting is pretty plush. We did adjust it to be a bit firm, as there was a lot of pedal bob. The ShockStop offered a very stable, linear movement that took out the major bumps very well, even over ruts, making every potential rough ride much smoother and more enjoyable. Redshift also makes a unique suspension stem, which does for the front end of a bike what their seatpost does for the rear.

Price: $229.99

www.redshiftsports.com 

KINEKT 2.1 

The e-bike-specific Kinekt 2.1 offers external preload adjustment and offers different springs for different rider weights.

 

Kinekt uses a dual-spring setup to cantilever you in a straight line. The first order of business is to choose the color of spring for your correct weight:

XS for riders 50–100 pounds (white)

S for riders 100–150 pounds (charcoal/purple stripe)

M for riders 150–200 pounds (charcoal/black stripe)

L for riders 200–260 pounds (charcoal/orange stripe)

XL 240–320 pounds (orange/
yellow stripe)

There’s also an easy-to-adjust knob on the back to adjust preload to allow you to adjust how soft the ride is. We found this seatpost to feel the most natural, making for a really plush ride, like having rear suspension. The spring action ramps up as it compressed and we found we didn’t bottom out easily, even trying it over some big bumps. It also only slightly bobbed a bit while pedaling, which actually helped reduce fatigue.

The Kinekt 2.1 is available in two lengths—350mm and 420mm—and diameters from 25.4mm to 31.6mm. There’s also a carbon 3.1 version that’s a bit lighter and a bit more expensive at $329.95.

Price: $249.95

www.cirruscycles.com

THE VERDICT

You really can’t go wrong with any of these three; all will add quite a bit of comfort to your ride. 

At $170, the Thudbuster ST is by far the least expensive of the three. It does a good job and holds its own, especially at the price. The two different approaches to springs between the Redshift ShockStop and the Kinekt 2.1 make it a really close race, as both offer phenomenal support. There’s a bit more bob when pedaling on the ShockStop, and the Kinekt post offers more fine-tuning in selection of springs and preload, as well as more choices of direct sizes and lengths. For the versatility and ride quality, the Kinekt is the clear choice for us.


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