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I’ve tested many different suspension seatposts over the years, but this is the first time I’ve got my hands on a suspension seatpost that’s also a dropper post.
The PNW Coast is one of these rare examples (BySchulz D.2 is the other) and I was more than happy to give it a try on the gravel roads I ride.
The Different Suspension Seatpost Designs
If you are looking for a suspension seatpost, you can currently choose between:
– Leaf-spring carbon seatposts like the Ergon Allroad Pro
– Spring-based suspension seatposts like the Redshift ShockStop
– Elastomer-based suspension seatposts like Cane Creek eeSilk
The PNW Coast uses a fourth method. Inside is a simple air-spring cartridge that provides up to 40mm of movement.
Another key difference from the rest of the suspension seatposts is that there is no rearward movement when the suspension compresses – it’s all up and down along the axis of the seatpost. This makes a big difference, but we’ll discuss that later.
Setting Up The PNW Coast Seatpost
The PNW Coast suspension dropper is the first product that I could not use right out of the box because you need a shock pump to properly set it up. After purchasing a shock pump, I started a similar process to other seatposts like the Redshift ShockStop – fine-tuning the spring rate.
PNW recommends the following air pressure for your weight:
50 to 75kg – 200 to 230psi
75 to 100kg – 230 to 260psi
100 to 125kg – 260 to 300psi
Following the PNW recommendation, I set up the air pressure at 260 PSI (84kg) and went for a ride.
I quickly discovered that 260 psi was simply too firm. So I dropped it to 220 psi. This time suspension was much more apparent but it also introduced some unwanted vertical movement (bouncing) when pedaling hard.
I ended with 230 psi, which was the best compromise between pedaling efficiency and suspension performance.
How Does The PNW Coast Feel To Ride?
The PNW Coast feels much less sophisticated than other suspension seatposts. The up-and-down movement is less enjoyable, as there is less polish in the movement itself.
While the Redshift ShockStop has a smooth, cushy feel, and PNW Coast is quite notchy. It moves harshly and stops the movement abruptly. It also does not rebound quickly enough when you encounter a quick succession of big hits.
For sure it works when you hit a big bump, but it is nowhere near the efficacy of a spring-based suspension seatpost.
One of the most important characteristics of a good suspension seatpost is how quickly you can forget it’s there. My favourite seatpost in this regard is the Ergon Allroad Pro, but the Redshift is not far behind it. The PNW Coast is not even in the same league because the notchiness constantly reminds you of its presence.
But we have to remember something very important here. PNW is advertising the Coast as a dropper post with some cushioning. It is not a suspension seatpost first. So really, it’s not quite fair to compare it with the best-in-class suspension seatposts.
The other thing to note is that PNW Coast is designed to help you with big bumps and not high-frequency gravel chatter. It is never going to respond quickly enough to appropriately deal with high-speed chatter.
Vibration Testing The PNW Coast
When comparing the vibrations you have to remember that the end results are very much dependable on the air pressure that you set it up with. Less pressure results in more effective suspension performance, but at the same time, a more bouncy and irritating feel. You really have to find what works for you.
For me, it was 230 psi as that was a spring rate that I could live with on a daily basis.
I conducted my vibration testing on my Jamis Renegade benchmark bike with Soma Cazadero 700C x 42mm tire set up at both 25 and 40 psi. The rigid seatpost was an FSA K-Force carbon. The saddle that I used in all of the tests was a cheap Accent model so I could rule out some of the suspension effect that would come from the saddle itself.
Vibration Test Results
You can see my vibration measurement procedure & outdoor test courses HERE.
On the fast gravel road, the PNW Coast did not provide show any improvement over the rigid carbon seatpost (as expected). It was even slightly worse with 40 psi pressure in the tires.
On the slow bumpy forest trail, the difference was much more apparent. At 25 psi, the tires are doing most of the work but the PNW was 4% comfier than the rigid seatpost. At 40 psi the difference was bigger (almost 7%) but I have to add that it subjectively felt much better than the rigid seatpost.
As I said before, you can get better results by lowering the pressure in the air cartridge (15% fewer vibrations is possible) but this is at the cost of bounciness, which I did not want to have.
PNW Coast Details
This is a dropper post first, so I think we should talk about the dropper functionality.
You can buy an external or internal cable-routed variant with different kinds of remote levers. The installation process is very simple, it took me no more than 10 minutes to set everything up.
An odd thing that you might encounter is the small side-to-side movement of the saddle (1-2 mm). I first thought that the saddle was not firmly attached, but I realized the seatpost itself had movement after re-tightening the main screw. But do not worry, you will not notice the play once you sit on your saddle and start riding.
I reached out to PNW for an explanation, and they told me that they engineered this movement to ensure the post can remain active even when grit and grime build up over time.
The dropper movement is quick and reliable, but again, provides a rather harsh sliding speed. I do not have much experience with other dropper posts so I can’t tell you if this is normal or a PNW Coast thing. But it works when you want it to work, and this is the most important thing.
I live near Warsaw so there are not that many places where I could benefit from this dropper post but I can’t wait to go to the mountains in summer to properly enjoy it.
Summary
I think that having a dropper that also gives you an additional suspension effect is a great idea. I really do!
Just don’t expect miracles from the PNW Coast. It’s a simple air cartridge solution and it was not designed to go head-to-head with the best suspension seatposts available. It works ok on bumpy forest trails but it doesn’t yield an improvement on fast gravel roads.
You can support the CyclingAbout Comfort Lab by purchasing a PNW Coast suspension seatpost on Amazon. Simply click HERE to make your purchase, and a small commission will come our way.
