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There is something funny about reviewing a product type that has been around for a while but until recently had mainly pretty poor options available. Suspension seat posts fit into this category. As bikes became more versatile and off-road riding became more popular, manufacturers sought out ways to improve comfort on bumpy terrain. Most of the energy went into frame-based suspension for mountain bikes, starting with suspension forks and then rear shocks. Modern full-suspension mountain bikes are incredibly capable and plush on an amazing variety of dirt but no one will argue they are as fast and responsive as a rigid framed road bike.
I believe the meteoric rise of “gravel” biking is due to people seeking out a fun, light, and fast riding experience that the big, heavy, soft mountain bikes can’t provide. There are a lot of ways to describe a gravel bike but for me, it’s about versatility. Comfortable geometry that borrows from endurance road bikes and hard tail mountain bikes but allows wider tires and a little more compliance. As a road biker and mountain biker, I find myself missing parts from both disciplines when I’m on one or the other. A gravel bike allows me to have the speed and quickness I love from the road and the adventure and variety I love from off-road. Ride a rigid framed bike off-road for long enough and you quickly remember why suspension was invented in the first place.
So, what to do? How do you keep the fun while getting a bit more comfort? Enter, suspension seat posts. Because these do not change the way the bike interacts with the ground surface, they allow you to retain all the aspects that make the light, non-suspended frame so fun. Done poorly and you end up with a squishy pedaling feel that zaps performance and negatively affects the fit of the bike. In this review, I’ll discuss how the RedShift Shockstop Suspension Seatpost handles these challenges. Spoiler alert, they did their homework.
Setting up the RedShift Shockstop Suspension Seatpost
Opening the box, you’ll find the seat post itself, an uninstalled spring, and an instruction page. A plastic mud “fender” is preinstalled on the post as well. Thankfully, the setup of the post is pretty straightforward and you don’t really need any mechanical skills to do so. The only tools you’ll need are standard hex keys but as I’ll mention later, you will probably want to have a long, ball-head 4mm for initial set up. The Shockstop is ready to go out of the box but you will definitely want to start by setting the preload to your weight and riding preference. Redshift provides guidelines for this, which gives a good starting point. To adjust preload (stiffness of the suspension), you twist a threaded cap at the bottom of the post to put pressure on the internal spring. Numbers on the cap provide an easy reference point and there is nothing complicated about this process.
According to the chart, if you are under 200 lbs and looking for a “comfort”-first experience, you should be able to dial that in with just the preload adjuster. However, if you are a larger rider or looking for a more “performance” oriented (read stiffer) setup, you’ll definitely be installing the additional included spring. The second spring is added inside of the main spring and increases the stiffness of the RedShift Shockstop post. While a bit messy, due to the grease, installing this second spring is quite simple. Remove the preload cap, spacer tube, and spring end cap, put the smaller spring inside the larger and reassemble in order. Then, use the preload plug to dial in the stiffness you desire.
As a 200 lb rider, I knew I was going to need the second spring and I installed it immediately before putting the post on my bike. My gravel bike is something that I ride on dirt AND pavement and I knew I didn’t want to be bouncing around while pedaling on the road. This lead me to an initial preload setting of 3 on the 1-5 scale. The only real downside to the adjustment method is that you have to pull the seat post out of the bike each time but that’s a pretty minimal issue. With an initial preload set, I was ready to put my saddle on and install the post.
Here is where the Redshift Shockstop Seatpost shows its very few “negatives.” The saddle clamp uses a two bolt system with a floating bottom rail support. Unfortunately, these bolts face inwards towards each other, making it quite awkward to use while the post is on a bike. Additionally, because they are deeper set into the seat post mechanism, they are a bit hard to reach with a standard multi-tool. Be sure to check that your multi-tool will work with the clamp before heading out on your first ride! This is where that long ball-head 4mm hex comes in handy. I found that installing my saddle was easier with the Shockstop post unmounted. For your first couple of rides, I suggest bringing that long 4mm with you until you dial in the adjustments. The good news is that once your saddle is where you want it, this won’t really be something you think about again.
Now the other “negative” is something that is difficult to avoid with a product like this, so I can’t fault Redshift for it too much. In order to accommodate the suspension apparatus, you need a minimum of 90mm of length available from your seat post clamp to the saddle clamp. Very short legged riders and those riding frames that are too big for them might be out of luck. The other challenge has to do with saddle setup. The Shockstop Seatpost uses a parallelogram linkage design to keep the saddle tilt consistent throughout the entire suspension range, which is a great feature. However, when the seat is lower in the suspension, it is further from the handlebars and closer to the pedals. To compensate for this, Redshift recommends installing your saddle 5mm forward and 6mm higher than you would on your rigid seat post. Now, here is where you need to be sure that you have the saddle rail space to do this. If you already ride your saddle pretty far forward in the rails, there is a chance you won’t have enough space to compensate. On my SMP saddle, this was a bit of a challenge. From a bike fit perspective, 3-7 mm can have a big impact for some people and it’s important to make sure you can maintain the measurements you need. For many, this won’t be an issue, but it’s worth considering before investing in the Shockstop Seatpost.
So, how does the Redshift Shockstop Seatpost feel out on the road and trail? In a word, awesome! I installed the post on my Santa Cruz Stigmata gravel bike and on my first spin around the neighborhood, I was immediately impressed with the smooth and effective suspension design. With only 35mm (1.4 inches) of travel, my expectations were pretty measured and I was thrilled to see them exceeded. The bad bits of road near my house that I would typically avoid or stand up for were more or less eliminated from impacting my butt and low back, two places I have injuries. Next, I swapped my road wheels and tires (700x28mm) onto the bike and went for a road ride to see how the post felt on pavement. The best metaphor would be that it made my 28mm tires feel more like 45mm tires, at least at the back end. You get the speed and rotational weight savings of the smaller tires while maintaining some solid comfort. My biggest worry was that I’d feel like I was bobbing around and that the movement would suck up my pedal strokes or mess up my saddle to peddle distance. Thankfully, with the preload set to a stiffer setting, this worry turned out to be unfounded. The suspension really only kicked in on impact and road high enough in the travel so that I didn’t notice any saddle height issues. As someone with a bad back, I really appreciated the way the Shockstop post allowed me to stay in the saddle for longer periods without standing. I definitely see this as a great option for road bikers who travel on rough roads or have and back issues.
Moving to the dirt and gravel, which this product is more geared towards, I put my 40mm gravel wheels and tires back on and went to a wooded trail near my house for a test ride. The trail includes smooth single track, rutted parts, mild roots, and a mildly technical section with baby head rocks, so I knew it would be a good place to see what the Redshift Shockstop could do. The best testament to the post is that I stayed in the saddle more often than I normally do, allowing me to pedal more effectively throughout the trail. The suspension has a dampness to it that does a great job preventing you from feeling like you will be bucked out of the seat when you go over bumps. Keep in mind this will really depend on how you tune the preload and there will always be a compromise between compliance and stiffness, just like any suspension option. I really appreciated it for the sections that are relatively smooth but have occasional ruts, roots that come out of nowhere. If you don’t see something and don’t stand, you don’t have to worry so much about the impact because the Shockstop has got your back, figuratively speaking. One place the post struggles a bit, at least with the way I had it set up, is long stretches of rutted dirt. It tended to have a bit too quick of a rebound for this and I lost some of the comfort I was getting on less consistent bumps. I believe that reducing the preload stiffness would help if you ride a lot of rutted trails.
Redshift Shockstop Suspension Seatpost Review Wrap Up
I want to make it clear that the Redshift Shockstop Seatpost doesn’t magically turn your rigid bike into a full-suspension ride feel and you will definitely still be experiencing the terrain. Keep in mind, it does nothing to the front end of the bike so don’t expect miracles up there. (For that, you’ll want to check out Redshift’s suspension stem option.) That said, to me, that’s sort of the point. I ride a gravel bike because I WANT to experience the trail in a way a big burly mountain bike doesn’t allow. Flicking the bike around and playing off all the different surfaces and conditions is a total blast and the Shockstop Seatpost doesn’t get in the way of that. Once dialed in to your riding style and personal preference, the Shockstop adds some very welcome comfort to your bike and offers some nice protection for your low back. The versatility is a great feature of this post, allowing you to choose a firmer or plusher experience. At 547 grams, the Shockstop weighs about twice as much as a rigid aluminum post. While this is a significant number, the trade-off is well worth it for the ability to ride longer and feel better at the end. The Redshift Shockstop Suspension Seatpost is available for 27.2mm and up, round seat post mounts and costs $229.99. Available at www.rei.com/redshiftsports or www.amazon.com/redshift.