Chris_W

RedShift Sports have recently launched a new suspension seatpost on Kickstarter that might be interesting for tandem teams looking to improve stoker comfort.



Even more interestingly, they've posted a useful comparison to 4 other competing suspension seatposts like the Thudbuster and Specialized CG-R, describing how their mechanisms and functions differ (which is obviously quite biased towards their own product).

I've used some of the other products by RedShift Sports, including their suspension stem and have been very impressed with the quality and function, so I expect their new seatpost will also be excellent. See my review of their stem on my Ride Far blog.

The Kickstarter goal has already been reached for the seatpost, but it's open to more backers until mid-May, but the one major drawback is that delivery isn't expected until at least November 2018.

Cyclist0108

I just checked this out at Sea Otter yesterday. Erik was kind enough to trust me with his bike, and I got to experience both the stem and seatpost. Based on my positive experience (and the extensive positive reviews of the stem), I placed my very first ever Kickstarter order for the seatpost/stem combo.

(I only just saw that I am replying to a thread in the Tandem section. I didn't evaluate this explicitly for a tandem, and don't currently own one. Apologies!)

mtseymour

The Redshift is a good design that's more suited to single bikes than tandems. This seatpost is un-damped and is intended for small, high-frequency bumps. According to their website,

"Damping is important for MTB because you're trying to absorb larger amplitude impacts. For high-frequency, small amplitude perturbations, it's better to have a very lightly damped system to maximize responsiveness. The plunger seals provide enough damping to prevent unwanted movement of the post, but otherwise, the system is free to respond quickly."

If you talk to stokers, it's almost inevitable that they will be bruised by big bumps. They can't quickly react like captains and un-weight their saddles. By using 2 springs, the Bodyfloat provides stability (at high cadence) and smoothly absorb a big bump. There's just no bouncing after a big hit. With an un-damped system like the Redshift, you have to compromise between stability and smoothing out big bumps.

twocicle

^^^ what he said (mtseymour).

My impression of real life usage of the new Bodyfloat Kinekt 3.1 vs. the visuals provided in the Redshift videos...

- Redshift appears to be a lot less effective, transmitting quite a bit of hits to the rider. You can see the saddle kick upward and rider is still impacted to some degree
- Redshift does not appear to handle high frequency chatter very well. The videos seem to show only the more substantial impacts will activate that suspension. Otherwise the linkage is rammed up to and kept at the top of the range.

Kinekt 3.1
While probably most of the tandem crowd here with a Bodyfloat, are using that on road tandems, we are using ours on a hardtail mtb tandem (Fandango). I set up the Kinekt 3.1 for my <100lb stoker with purple springs and backed off the preload to near, but not quite at, full top linkage range. This setup is allowing my stoker to float within the spring range while still very stable, but the post still handles bigger hits very well. Smaller vibrations are not an issue on a mtb bike as the bigger tires (vs road) absorb those inputs. The spring rates are linear, which provides a very smooth up/down glide path that does not feel uncontrolled or abrupt. We have not yet found the need to extend the linkage range by removing the bottom-out stopper from the top spring (a suggested tweak by Cirrus support for more offroad linkage travel range).

For a road setup, we would use slightly lighter weight (white) springs, as that setup would be intended to handle high frequency vibrations and typical road hits.

Happy with the adaptability and performance of this post.

Carbonfiberboy 

We are using the Specialized COBL GOBL-R or what ever they call it now (CG-R). Stoker is happy with it. Takes out the buzz and small hits, but not the big ones. OTOH very light, no bother, works well with saddle bags, etc., absolutely no stoker bounce. No need to call the big ones. When I level the pedals, Stoker knows to raise her butt.