Redshift ShockStop Pro suspension seatpost review: An awkward middle ground

A more performance-oriented tune and a lower weight, but still kinda heavy and with less suppleness than you might want, too.

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There’s no shortage of choices these days when it comes to add-on suspension seatposts for gravel bikes, all of which are intended to provide more comfort than a rigid post. One of the ostensibly more performance-minded options is Redshift Sports’s ShockStop Pro, which uses the same basic design as the standard ShockStop, but was retuned for a firmer ride and pared down for reduced weight.

Just like on the standard ShockStop suspension post — and in contrast to the telescoping designs that were more prevalent on mountain bikes of the 1990s — Redshift uses a parallelogram-style linkage on the ShockStop Pro, with a small piston at the bottom that compresses a spring stack hidden inside the seatpost shaft. But whereas the standard ShockStop uses a series of steel coil springs, the ShockStop Pro features an elastomer-based system that’s designed to offer a firmer ride, particularly off the top. The spring rate is also more progressive, which ends up limiting the travel to a more modest 20 mm as compared to the 30 mm on the standard ShockStop.

That elastomer stack is lighter than steel springs, too, and shedding more grams are the ShockStop Pro’s hollowed-out pivot pins and more aggressively machined linkage arms. A profiled mudguard (held on with magnets, of course) helps shield the linkage from mud and grime, while the internal guts are protected by seals made by SKF. 

The ShockStop Pro uses the same general layout and pivot geometry as the standard version, but with a major rework of the spring stack. Photo: Redshift Sports.

RedShift Sports only offers the ShockStop Pro in a 27.2 mm diameter, although given that size’s prevalence these days, that’s not really a big deal (especially since it can be shimmed for larger-diameter seat tubes). Two lengths are offered — 280 mm and 350 mm — and claimed weight for the 27.2×350 mm version is 415 g. Actual weight for my sample was slightly heavier at 442 g, and retail price is US$300 / AU$475 / £280 / €330.

So, how’s it ride?

On paper, it would seem the ShockStop Pro should perform very similarly to the Cane Creek eeSilk. Both use parallelogram linkages, after all, and both rely on elastomers to provide the squish. But in practice, they’re surprisingly different beasts. If you’ve tried suspension posts before, but found them to feel a little too soft and floaty, then this ShockStop Pro might be for you.

Redshift Sports has intentionally tuned the ShockStop Pro to be very firm, particularly off the top. Whereas just about every suspension seatpost on the market is designed to be run with sag — i.e. the post sinks into its travel a bit just with your body weight on it — the ShockStop Pro is fully extended most of the time. In addition, whereas most suspension posts are designed to be very active, particularly on smaller bumps, it takes a decent-sized hit to get the ShockStop Pro moving at all, and even then, the spring rate is very progressive.

As such, the ShockStop Pro doesn’t strike me so much as a comfort aid as it is a big-hit supplement: something to take the sting out of more severe impacts that might bounce you off-line or just otherwise catch you off guard.

Pulling off the rear mudguard reveals some clues to how the ShockStop works.

Since it works differently to other suspension posts I’ve tried in the past, I found myself riding the ShockStop differently, too. More active seatposts prompt me to stay seated more often to take full advantage of the comfort and ancillary traction benefits. But on the ShockStop Pro, I reverted back to my usual habits of floating above the saddle when things were rough, and relied on the post mostly for stuff I wasn’t able to anticipate.

The pivot placement is worth discussing, too.

Companies have taken different approaches to the direction in which the saddle moves during an impact. Cane Creek’s eeSilk moves mostly rearward at first, whereas the Cirrus Cycles Kinekt’s path is predominantly downward. For the eeSilk, this means the effective reach changes constantly while riding (particularly on bumpy terrain), so much so that it’s important to account for that movement when setting your saddle setback. Alternatively, the Kinekt’s more downward path means you need to account for sag when setting saddle height, but the reach stays fairly constant.

But the Redshift? It splits the difference between the two. There’s a hint of rearward movement initially in the travel, but not much. And then from there, it’s mostly vertical movement to more effectively suck up the jolt. At least in my opinion, the travel path on the Redshift is the least disruptive of the three.

Another pro on the ShockStop Pro is its impressively compact and svelte appearance. Despite all the extra hardware, Redshift has done a great job of minimizing the bulk – and it certainly helps that the elastomer stack is hidden away inside the seatpost shaft. Redshift is clearly still enamored with magnets, too, as one is used to neatly keep the rear mudguard in place without needing any additional hardware.

It’s not all roses here, however. 

The firm feel most definitely won’t be for everyone. Although some will invariably equate that firmness with efficiency, that’s not always the case. On smoother surfaces, I definitely don’t want a lot of movement. But since there isn’t a lot of movement on rougher ones, either, there just isn’t as much of a comfort benefit here as you get with the eeSilk or Kinekt. Ultimately, I found myself preferring the ShockStop Pro more on my all-road bike than my gravel one. 

Pivots are user serviceable, although it’s also dependent on the skill level of the user.

There’s also the question of tunability. I’ve long been a huge proponent of suspension in general, but I’m also adamant that it be properly tuned to suit the rider and conditions. However, Redshift Sports ships each ShockStop Pro with the same elastomer stack regardless of rider weight.

“We found that with the shorter travel and high-progressivity spring rate of the elastomers, a much wider range of riders were comfortable on the same spring setup,” explained Redshift Sports co-founder and principal engineer Stephen Ahnert. “The regular ShockStop Seatpost is designed to be ridden with sag, and the coil spring provides a much less-progressive linear spring rate, which meant that fine-tuning the preload/spring rate was quite important to provide that plush, floaty feeling throughout the travel.

“With the Pro seatpost, we were shooting for a more traditional feel, meaning that the seatpost is more or less topped out until you encounter a bump, at which point the spring rate ramps up quite quickly through the shorter travel. Bottom line: yes, lighter or heavier riders will have slightly different experiences on the Pro seatpost, but based on our in-house testing with riders between 120 and 220 lb (55-100 kg), the stock elastomer setup seems to work quite well for the vast majority of riders.”

That said, Ahnert does admit that alternative elastomers are actually available if someone feels like their ShockStop Pro seatpost is just too stiff or soft for them. However, this isn’t at all obvious on the product page, and replacement elastomers aren’t even listed on the company’s list of spare parts.

The Redshift Sports ShockStop Pro seatpost is also pretty hefty. Granted, at 442 g, it’s more than 120 g lighter than the Kinekt. However, it’s also almost 100 g heavier than the equivalent eeSilk, which is also almost US$100 less expensive and still offers a performance-oriented ride. Worse yet, Cane Creek offers a version of the eeSilk with a carbon fiber shaft that saves another 50 g on top of that and is only US$20 more than the ShockStop Pro.

The Redshift Sports ShockStop Pro may be a lightened and stiffened version of the standard ShockStop, but it’s still somewhat hefty.

To be fair, weight-conscious riders who don’t need all the stock shaft length can just cut off the excess to save some grams – to the tune of about 0.5 g per millimeter of post removed. According to Ahnert, the longer version of the ShockStop Pro seatpost can be shortened by up to 175 mm, while 105 mm can be safely lopped off of the shorter one, which would bring the claimed weights for both down to about 328 g. But then, you can do something similar to the eeSilk and Kinekt posts, too, so it’s not really much of an advantage.

There’s also the question of sizing. While both Cane Creek and Cirrus Cycles offer their posts in multiple diameters, Redshift Sports only offers the ShockStop Pro in 27.2 mm. That’s hardly a deal-breaker since that’s the most common size, and it can also be shimmed to fit bigger seat tubes, but it’s something to note regardless.

And what about long-term durability? Well, those elastomers definitely won’t last forever, although several years of regular use should be expected at the very least – and hopefully Redshift will keep replacements on hand for a long, long time. A bigger question mark is the pivots since they’re wholly exposed to the elements and much more difficult to replace, although Ahnert says that really hasn’t been an issue.

“We don’t expect most riders to ever have to replace the bushings on the seatpost unless they’re regularly riding in very wet, sloppy conditions,” he said. “However, if they do develop noticeable play, we handle these on a case-by-case basis covered by our lifetime warranty. Depending on the location and technical skill of the customer, we’ll either have them send in the seatpost for service, send a bushing replacement kit, or replace the seatpost. To date, we’re handling less than a dozen of these replacements annually.  

“Functionally, the exposed ends of the shafts on the Pro post are essentially the same as the covered ends on the regular seatpost. The plastic endcaps on the regular post are aesthetic covers – they don’t provide much (if any) sealing against water intrusion, and the inboard sides of the bushings are uncovered in both the regular and Pro versions. Our internal ride-testing and customer service logs have shown no discernible difference in bushing wear between the two designs.”

OK, so then who’s it for?

That’s a great question. Unfortunately, the ShockStop Pro seatpost feels to me like it strikes an awkward middle ground. On the one hand, I actually quite enjoy the firm feel for certain types of riding, the well-considered travel path, and the sleek appearance – all of which should make the ShockStop Pro well suited for road/all-road riders looking for a little bit of extra reassurance on particularly poor surfaces. 

But on the other hand, it’s just too heavy to really appeal to weight-conscious roadies who might not be able to justify an extra 200-250 g of weight for such minimal benefit, especially given how the suspension action is already so polarizing. Moreover, the action strikes me as too stiff to offer enough of a benefit on gravel.

I adore Redshift Sports’ ShockStop suspension stem, so much so that it’s been a near-permanent fixture on my Allied Allroad (and I’m considering upgrading to the Pro version). But this ShockStop Pro seatpost feels like it falls just a little short. Redshift Sports: how about you tool this thing up in carbon fiber to lop off 100 g or so, and then we chat again, eh?

More information can be found at www.redshiftsports.com.

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