I have tested many different suspension seatpost but never a suspension seatpost that is also a dropper post. PNW Coast suspension dropper post is one of the rare examples of this kind of product so I was more than happy to test its suspension properties on my test tracks.
When reviewing the Redshift suspension seatpost I mentioned that there are a couple of different approaches to suspending the rider and spring-based are the most common ones (Redshift is using springs). Then there are solutions like Ergon CF3 / Canyon VCLS 2.0 seatpost that try to get as much flex as possible from a rigid carbon post. PNW Coast uses a simple air suspension cartridge that provides up to 40 mm of movement and it works differently than anything that I have tested before. The main difference is that there is no setback so all the movement is just up and down (for comparison Redshift suspension seatpost is moving downwards and rearwards at the same time). This makes a big difference but let’s go one step at the time…
Setting up the suspension
PNW Coast suspension dropper post is the first suspension that I could not use right out of the box because you need a shock pump to properly set it up. After getting one I started a similar process that I had with Redshift suspension seatpost: fine-tuning of the suspension effect.
PNW is recommending different air pressure depending on your weight:
50~75kg, PSI: 200~230psi
75~100kg, PSI: 230~260psi
Following the PNW recommendation, I set up the air pressure at 260 PSI (I weight 84 kg but during my suspension seatpost testing I found out that I prefer firmer setups) and went for a ride. I quickly discovered that maybe 260 PSI was not that good idea because the suspension was quite firm and I did not feel good using it. So I changed the PSI to 220 PSI. This time suspension was much more apparent but I also introduced unwanted movement when pedaling hard so I knew I have to go up (PNW recommendation is to find the pressure that will result in no SAG when pedaling in your favorite position). After a few more trials I ended with 230 PSI which was for me the best compromise between pedaling efficacy and suspension effect.
How does it feel?
In one sentence: PNW Coast suspension feels much less sophisticated than something like Redshift suspension seatpost. The up and down movement is less enjoyable in the first place, but there is also the less finesse in the movement itself. Redshift suspension is more like a soft, cushy suspension and PNW Coast is like a hammer-like suspension. It moves harshly and stops the movement quite quickly. It also do not rebound quick enough when you encounter a series of big bumps. So yes, it generally helps when you hit a big bump but it is nowhere near the efficacy of spring-based suspension like Redshift offers. Also, one of the most important factors of a good suspension seatpost for me is how quickly I can forget about it and enjoy the ride. The best in that department is still VCLS 2.0 seatpost but Redshift is not far behind it. PNW Coast is not in the same league because its movements constantly remind you that you have a suspension seatpost.
But we have to remember something very important here. PNW is advertising Coast as a dropper post with an additional suspension effect. It is not a suspension seatpost in the first place (that has added a dropper to it – like Redshift will be doing with their suspension seatpost in future). So naturally, it is not totally fair to compare it with the best in class suspension seatposts. The other thing is that Coast suspension was designed to help you with the big bumps and not the high-frequency gravel chatter. It is not quick enough to deal with that challenging scenario.
And the results?
When comparing the suspension effect you have to remember that the end results is much dependable on the air pressure that you set up. The less PSI the more effective the suspension (but at the same time the more bouncy and irritating it will be). So you have to find the best air pressure for your needs. Like I said, for me it was 230 PSI so, although, 220 PSI was resulting in a much better suspension effect, I am showing the results of 230 PSI because it was the best compromise that I could live with on a daily basis. The other thing is that I will deliberately not show you the results of PNW dropper post compared to Redshift yet (mainly because I am still planning to do a big suspension seatpost shootout in coming weeks but also because I really think that it is much fairer to compare PNW Coast with a rigid carbon post like FSA K-Force, that also has no setback).
I did a test on my benchmark bike with Soma Cazadero 42c tire set up at 25 and 40 psi. The saddle that I used in all of the tests was a basic Accent one so I could rule out the suspension effect that could come from something like Brooks C17 saddle. On a fast gravel route the PNW, as expected did not provide any real improvement over the rigid carbon seatpost (it was even slightly worse at 40 psi because up and down movement was not compensating for the rigidness of the aluminum tubing of the seatpost itself). On the slow bumpy forest road the difference was much more apparent. At 25 psi tires are doing most of the work but still PNW was 4% comfier than FSA seatpost. At 40 psi the difference was bigger (almost 7%). But I have to add that subjectively it felt much better than rigid seatpost and like I said before, you can get better results by lowering the pressure in the air cartridge (even 15% less vibrations but at the cost of bounciness which I did not want to have).
Yes, this is a 100 mm dropper post in the first place so I think that it is about time to talk about the dropper functionality. You can buy an external or internal cable routed variant and with different levers (or even without the lever if you already have one). The installation process is very simple (it took me no more than 10 minutes to set everything up and you can watch this installation video from PNW to know exactly what to do). The one odd thing that you will probably encounter when installing the saddle is the small (1-2 mm) side to side movement of the saddle. I first thought that the saddle was not attached firmly enough but after tightening the screw as hard as I could I realized that it was not the saddle attachment issue but the slight movement of the dropper itself. Yet, do not worry about that because once you sit on the saddle and start riding you will not feel that movement at all. At least I did not feel it. I reached to PNW for explanation and they told me that they engineered this movement to ensure the post stays snag-free as grit and grime build up over time.
The dropper movement is quick and reliable but again, provides rather harsh slip in friction. I do not have any experience with other dropper posts so I can’t tell you if this is a general rule or a PNW Coast thing but, to be honest, I don’t mind it. 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.
To sum up
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 suspension itself. It is a simple, air cartridge solution and it was not designed to go head to head with the best in class suspension seatpost so it is not wise to compare it that way. But it works on a bumpy roads so if you are in need for a dropper post, I could sincerely recommend buying one from PNW. You will appreciate the additional suspension effect for sure!