Specialized Stumpjumper S-Works Vs Stumpjumper Comp Alloy 21

What kind of mountain bike do you really get for your money these days? There may be a ton of stink around top-shelf expensive bikes, but are they worth it? Will riders have just as much fun and get great performance from a lower-tier bike? We were lucky enough to have one of each on hand and over the past several months, we've logged a lot of miles on the Specialized Stumpjumper S-Works and Stumpjumper Comp Alloy. We're ready to share how each of them fared and where we think you may want to put your money.

Highlights

The Stumpjumper Comp Alloy isn’t the base model option but we believe that the Comp Alloy lends itself to comparison with the top tier S-Works for purposes of our review. The Stumpjumper Alloy model features FOX suspension and powerful SRAM G2 brakes. Also present is a reliable Trans X Manic dropper post, and durable Roval rims. SRAM's NX Eagle drivetrain is budget-oriented but billed as reliable. To us, the collection of parts make the Comp Alloy a no-nonsense workhorse.

The Comp Alloy model shares the same asymmetric aesthetic of its more expensive brethren but possesses the tried and true FSR suspension. Unlike the 2020 Stumpjumpers, the travel has been reduced to 130mm of travel in the rear, and 140mm of travel in the front. Additionally, the range of models of yesteryear has been simplified. Extraneous models (Downieville, ST, Pemberton), as well as 27.5-inch wheels, were eliminated throughout. The Stumpjumper range as a whole, Stumpjumper and Stumpjumper EVO, is now neatly distinguished between the desired intentions. This shorter travel platform can be seen as an XC rider’s ticket to accessing more technical terrain, or conversely a downhiller’s XC bike. That may be a roundabout way of saying ‘trail bike,’ but classifications have become somewhat blurred these days. Fortunately, Specialized has made it easy by offering the EVO for more demanding terrain without dipping into enduro territory. Either way, the bike feels very much like the Stumpy has for much of its life as a trail bike. The active, supple suspension coupled with the neutral seated position is instantly recognizable.

What is interesting about the Stumpjumper range is that both the carbon and alloy frames achieve a similar suspension feel but in different manners. As opposed to the FSR suspension layout on the alloy model, the carbon frame forgoes the chainstay pivot in exchange for a single pivot flex stay. For a full dive into how that works, check out our First Ride Review of the new S-Works.

The Specialized Comp Alloy is heavier than the S-Works frame by over a kilo at 3,490g (claimed.) The alloy frame also lacks the beloved SWAT compartment on the downtube, but retains geometry adjustment. The frame has internal cable routing that is reasonably well managed, but far from the internally tubed routing seen on the carbon frame.

Specialized engineers chose to eliminate the rear pivot on the carbon models in an effort to both reduce weight and boost efficiency. At 2,240g for an S-Works S4 frame (including rear shock, axle, hardware, and armor) the frame is over 100g lighter than the previous generation. That reduction may seem insignificant, but the frame itself has been made stronger, stiffer, and much longer than before. Having owned the previous generation, the stiffness claims easily stood up in comparison.

Apart from the suspension and SWAT compartment, the two models actually have noticeable differences in geometry.

Geometry and Setup

The differences in geometry between these two bikes were surprising. They felt different on the trail, but we weren’t able to put a thumb on the culprit until consulting with their corresponding geometry charts. The most significant of which was the seat tube angle and chainstay length. The differences in seat tube angles of 77.7-degrees vs. 76-degrees and chainstay lengths of 444mm vs 432mm for the Comp Alloy and S-Works models, respectively, were immediately noticeable (Low setting). These two major differences further differentiate these two models and their resulting feel on the trail.

Setup

We found the seated position on the Comp Alloy to be somewhat more upright than that of the S-Works. But, we didn’t do anything differently with the fit. On both models, we preferred the saddle to rest in the middle of the rails, and the 50mm stem was adequate.

Over the longer duration with the S-Works we tried different bar widths from 760 to 780. In addition to bar width, we tried both the 50mm stem that came stock and a 40mm stem for comparison. Those changes were noticeable, but are not relevant in the comparison between these two models.

On The Trail

Both the S-Works and Comp Alloy bikes were taken to a variety of different locations throughout the testing period. From loamy, alpine singletrack to the rock-strewn desert, the Stumpjumpers have often been the bike of choice.

The trails here in Idaho are particularly well suited to the intentions of these bikes. The local trails require a great deal of climbing to get into more interesting terrain. Climbing these smoothed-out trails are ideal for a lighter-weight, shorter travel bike. As we ventured beyond the local buffed-out trails and into steeper, more rocky terrain, the bikes’ limitations began to present themselves. It was in those conditions that we were able to really distinguish between these two bikes. The differences, both up and down, illuminated themselves the harder we pushed.

DH/Technical Performance/Fun Factor

Both bikes were capable of descending rapidly, though the two reached those speeds in a different manner. The S-Works model required a confident pilot as the velocity increased, but could be ridden to impressive speeds. The Comp Alloy model, on the other hand, was calm and composed until it wasn’t. There was a clear line the Comp Alloy would not surpass.

Coming from the S-Works, the Comp Alloy was noticeably less stiff and direct. Instead, we were met with composure as speeds picked up. The longer rear center coupled with the extra heft worked very well to retain stability. Inversely, the S-Works is noticeably lighter, in addition to having a significantly shorter rear center, which allowed for greater maneuverability. On tighter, more natural trails, few bikes share the same agility and precise riding characteristics exhibited by the S-Works.

Is one model better than the other on the descent? That’s an interesting question. We enjoyed the razor-sharp handling and lighter weight of the S-Works on most terrain. Those characteristics were immensely enjoyable on tight, tricky trails. On the other hand, we found that the Comp Alloy complemented steeper, more wide-open terrain with its extra heft and longer rear center. The only thing that is keeping the Comp Alloy from blowing the S-Works out of the water on wide-open trails is its suspension. We didn’t dislike the Grip damper of the Rhythm 34 fork, nor did we particularly dislike the Float DPS shock, but the S-Works FOX factory suspension with the Grip 2 damper was far more supportive and precise on descents. Apart from the fork, we also needed greater damping and progression in the rear to prevent the bike from blowing through its travel in those conditions.

For the Comp Alloy to descend as well as a bike that costs almost three times as much is pretty astonishing. We believe anyone plopping down $3,400 for the Comp Alloy will be pleasantly surprised.

Rear Suspension Performance

One of the many questions regarding the rear suspension is whether there is a difference in feeling between the two. Yes, but it isn’t massive. The carbon model feels a bit more taught and ‘lively.’ The alloy model, on the other hand, has the more ‘open’ and ‘supple’ feel traditionally associated with the FSR linkage. Now, again, the feeling is similar. It may be similar enough that we would hazard a guess that the average consumer may not feel a difference between the two bikes.

What we did notice between both bikes was just how linear the rear end was. Fortunately, volume reducers can be added to increase ramp, but that led to other issues. With 25% sag and the larger 0.8 in^3 volume reducer added, we found that we wanted additional low-speed compression for support. The S-Works had the ability to add noticeable low-speed compression independent from the three-position climb switch. The Comp Alloy's rear shock lacked that level of adjustment. On the Comp Alloy, we settled on keeping that FOX DPS performance rear shock completely open after finding that the middle ‘Trail’ mode from the climb switch offered more support than the front could deliver without becoming harsh.

With added compression and longer descents, we were also able to find the limits to the DPS shock's ability to manage heat. Faster descents in excess of 2,500 feet resulted in a rear-end that began to feel like a mushy mess. The only real solution would be to add additional oil volume in the form of a reservoir. The shock’s limits are not particularly surprising, nor are they a huge deterrent, but another example of this bike's balance between the climb and descent.

Unique Features

The SWAT Box downtube compartment found on Specialized carbon models is easily one of our favorite features. We at Vital love surprises, and there may never be anything more exciting than finding a tasty little snack hidden in the downtube on a long ride. Along with little downtube morsels, we could easily fit our tools, a spare tube, and occasionally a light rain jacket in the downtube. This feature ended up being one of the larger draws to the S-Works model. The ease of use is astonishing, and this is one of the major reasons we would have chosen to ride the S-Works model over the Alloy Comp model.

Geometry

The adjustable geometry was not particularly hard on either bike. The carbon S-Works has an offset yoke attachment while the Comp Alloy has an elliptical chainstay pivot screw. The geometry changes for both were nearly identical, though the Comp Alloy adjustment adds 4mm to the chainstay. We didn’t have any issues with either one but found the Comp Alloy solution to be both easier and more intuitive. Throughout the test, we rode both in the Low setting.

Perceived Weight

Everyone that lifted the S-Works bike had something to say about its weight. The thing is light. At a hair under 27 pounds, the weight of the carbon frame and its components had been obsessed over. Those weight savings show both visually as well as on the trail. From the intricate curves of the frame to the ability to easily lift the bike and pick a line, the bike exuded precision. Though, as speeds increased on the descents, the lightweight became a dodgy endeavor.

The Comp Alloy on the other hand is $6,500 cheaper and over six pounds heavier. On the trail, it did feel heavier. That sensation could be chalked up to the suspension feeling a tad less efficient in addition to the extra heft. But, the seated position was fantastic on this model which made those two quibbles a bit less pronounced. On the descent, the extra heft of the Comp Alloy was only felt as the trail became tighter and more unnatural.

Climbing

Climbing was handled admirably by both bikes in this test. The S-Works does not have that exciting, racy feel of a purebred XC bike. But, there’s no question, the bike is sneaky fast. A dark horse of sorts. A really expensive dark horse. We found ourselves casually motoring away from our riding buddies on more than one occasion. With plenty of traction, the chassis would prefer a rugged Alpine trail compared to a buff road. Either way, the bike was able to arrive at the top of any trail far quicker and with less effort than we would have expected. It’s no XC whip, but the classification of ‘light trail’ is apt.

The Comp Alloy succeeded in arriving at the same point with noticeably less spunk. The bike doesn’t jut forward like the stiffer, lighter S-Works. The thing is, the bike may have been slower on most climbs, but we were able to clear a few steeper sections of trail on the Comp Alloy. Not only were we surprised by our ability to clear those sections, but it was done with less body English. It wasn’t for a lack of traction on the S-Works, but we had to fight a little harder to stay forward.

These trails would be considered an extreme case. Nonetheless, the geometry on the Comp Alloy suited us quite nicely in these situations where the longer rear center kept us grounded and the steep seat tube held us in a better position. We never disliked the geometry on the S-Works, quite the contrary. The S-Works was incredibly comfortable and we never felt like we were hanging off the back of the bike.

Overall, there were definitely some surprises here in the test. It was no surprise that the S-Works was indeed much spunkier. In the vast majority of situations, the S-Works is a faster bike. We were content going slower on the Comp Alloy, but the S-Works had a tendency to excite us on the climbs. It made us want to drive the pedals that much harder to catch someone or just get to the top quicker. But, despite the less spunky nature, we were genuinely impressed with the Comp Alloy's ability to scale steeper terrain.

Build Kit

Dropper post

The AXS dropper post was neat on the S-Works model, but we found that the post wouldn’t drop if we were too far back on the saddle. We found ourselves having to briefly shift our weight forward to get the post to release. That annoyance wasn’t quite enough for us to dislike the post. But, considering the price, we expect the post to drop without any required body English.

At the beginning of the test, we were interested to see if this wireless reverb would be trouble-free. Happily, the post had zero reliability issues. In fact, we never touched it apart from removing the battery for charging.

The Manic dropper on the Comp Alloy is one we have spent a lot of time on here at Vital MTB without any issue to mention. The post on this test bike continued that trend. The Dropper does droppy things without any thought. It’s not flashy, but the Manic post has continued to impress. Underrated? We certainly think so.

Fork Performance

The FOX 34 on both models felt very different. The FOX Factory 34 with Grip 2 damper found on the S-Works model was massively supportive. The fork was so supportive that we found it somewhat harsh if we weren’t pushing the bike on the descents. It took us a while to get the proper setup, but ultimately we were very happy with how it performed.

The FOX 34 Rhythm fork found on the Comp Alloy was the inverse of the Factory model. We really enjoyed how the fork felt when riding at a somewhat slower pace, but it just couldn’t quite keep up once things became hectic. The suspension performance was still pretty darn good considering the price.

Tire Performance

The stock Specialized tires were very, very impressive. They were consistent and predictable on the terrain we tested. We had no issues with their performance, and the latest tire compounds and knob architecture have elevated Specialized tires to relevance. For the price, we would have a hard time choosing another option out there.

Wheel Performance

The wheels on both bikes were completely different. The stiffer, lighter carbon hoops on the S-Works model were flawless. We checked the wheels for true a couple of times but never had to touch them with a spoke key. They are as perfectly straight and evenly tensioned as the day they came. In addition, if the Roval carbon hoops happened to fail, they would be covered under warranty and the original owner would receive a replacement. A subsequent owner of the wheels would receive a 2-year full warranty and a tiered discount for 3 years after that.

There was one thing that held the wheels back, though. The issue, surprisingly, involved the DT Swiss 240 hubs. The DT Swiss hubs had some unsettling bouts. There were a few instances where the hub would act like it was about to slip. The engagement would push through a couple of degrees before it would catch. It was very hard to reproduce, but we did notice that it had a tendency to rear its head when temperatures dipped below 40 degrees. We analyzed the internals and found that the grease was adequate and not excessive. To combat this issue, we tried adding freehub oil to lower the viscosity at these lower temperatures as well as pulling on the single spring to add overall force towards the engaging side. After those two things, we haven’t noticed any issues. This was the one thing that held back the S-Works model from being completely trouble-free throughout the entire year of riding.

The Roval alloy wheels on the Comp Alloy, on the other hand, were suffering by the end of the test. There were multiple flat spots, dents, and wild variations in spoke tension. One of the spokes ended up completely disengaging from its corresponding nipple while on a ride. The exposed threads on the spoke revealed that spoke-prep did not seem to be present. For comparison's sake, we rode these wheels far less and tended to them equal to that of the Control Carbon rims. Sadly, we would need to lace up a new set of rims on the alloy set after this test to be fully confident.

The thing that we did enjoy from the alloy wheels was their compliance. Compared to the Control carbon hoops found on the S-works, the alloy wheels were considerably more compliant. Because of this compliance, we could see ourselves enjoying this wheelset with inserts and downhill tires on an enduro platform.

Brake Performance

The Guide G2 brakes specced on both performed fine. We found ourselves going back and forth on whether the power was sufficient for the intention. Ultimately we decided that the brakes were adequate. Nothing mind-blowing, but they did the job. We would have liked a tad more power, but the extra power would come with greater weight and more force exerted on the lighter FOX 34 stanchions. So, we settled for the less than exciting power in exchange for greater modulation and smooth power delivery. On the plus side, the lever felt pretty darn good, and the brakes faded less than we would have expected.

Drivetrain Performance

The drivetrain performance of the AXS model was somewhat shocking. It’s seriously, ridiculously good. We randomly punched the derailleur, rode it as hard as we could, and the whole system never skipped a beat. No adjustments throughout nearly a year of riding hardly computes. Yes, it’s expensive, but the AXS system succeeded in doing what we never had thought possible just a few years ago.

The NX drivetrain on the Comp Alloy is an entirely different beast. We found the shifter both spongy and cheap, but the action wasn’t completely vague. We also found that the NX derailleur had a tendency to get hung up when asked to shift down the cog to a harder gear. It was rather unsettling to put the power down after trying to shift, only to find the crank falling away without resistance. We consulted with a local shop that confirmed this issue. Luckily, NX derailleurs presenting this flaw were warrantied.

What also bothered us with the Comp Alloy was the lack of a chain guide for the front chainring. The S-Works model comes stock with a chain guide, and we believe that the Comp Alloy deserves the same treatment. A chain guide will add much-needed security to the system.

Noise

Both bikes were incredibly quiet. In fact, they were similar in this regard. Though, The S-Works model created different sounds based on what sorts of things we decided to stuff in the SWAT box that day.

What Would We Change?

These bookend models allowed us to think about what our ideal build would be for our own personal, albeit snobbish, preferences. If we had $10,000 to burn and fit the mindset for this bike's intentions, then we would unquestionably purchase the Expert model and replace the aluminum hoops for considerably lighter carbon ones. At $5,800 for the Expert and an additional $1,500 for the wheels, we would come out with almost identical performance for $2,500 less.

That said, it may be hard to give up AXS. An additional $600 for GX AXS upgrade would put us at just under $2,000 less than the S-Works model…with an additional wheelset and shifter/derailleur. The point here is that the S-Works is a huge amount of money. If there were actually parts available and bikes to buy, then we would have a very hard time justifying the price.

Stepping to the other end of the spectrum, the Comp Alloy has some serious potential. We would love Specialized to make a model that bolsters its downhill performance. By adding a reservoir shock, upgrading the fork to Performance Elite, and throwing on more powerful brakes, the bike could handle a lot more without trying to do too much. Additionally, a Shimano Deore drivetrain, as well as burlier tires to protect the rims, would be a treat.

The Comp Alloy will never win a race to the top compared to the S-Works. Dropping weight only gets expensive and tedious. Instead, the Alloy frame is an excellent platform for using its extra weight and brilliant geometry to make a fun, short travel ripper. It wouldn’t be particularly unique, but we believe that the reasonable, balanced geometry would be conducive to downhill performance that the current model cannot provide.

Daydreaming aside, we would have liked to see Shimano’s SLX drivetrain on this bike for its durability and better feel over the Sram NX. In addition, we would recommend a tire insert for the rear wheel (at least) for protection.

Long Term Durability

We have to make a confession regarding the durability of the S-Works throughout the past year. The goal was to hammer this bike into the ground with the intention of pushing at least something beyond its breaking point. Sadly, we came up short of our goal. Despite randomly punching the derailleur and riding the bike well beyond its intended purpose, the thing didn’t flinch. It was somewhat humbling. Other than the expected brake pad swap/bleed and basic suspension service, there wasn’t a single issue beyond the DT Swiss 240 hub troubleshoot. There was so little time spent in the shop that it was almost impossible to wrap our mind around. The durability of the bike was stunning. Cosmetically, the black color began to look drab and heavily scratched. Fortunately, a layer of protective film brought the black frame back to life.

As far as maintenance of the S-Works goes, we don’t see things going south anytime soon. When the time comes for replacing bearings, the process is fairly straightforward and parts are common (if they are in stock).

The Comp Alloy has experienced a different fate. Apart from the basic maintenance shared with the S-Works model (brake bleed and suspension fluid), the NX derailleur required a warranty replacement and the wheels were on their last legs. Along with the drivetrain and wheels, the cables and housing will need replacement in the near future.

If anything seriously bad happens to either bike, Specialized has a Lifetime Warranty for all models of their bikes.

What's The Bottom Line?

It is reasonable to assume that there is not a single person on planet Earth that will be upsold by $6,500 while purchasing a bike at a shop. But, what is the difference between these two models? From one end, the Comp Alloy delivers on the workhorse mantra that we would expect from spending $3,400. It got to the top of any climb without any issues, and the descents were incredibly fun. Apart from the riding experience, the bike requires considerably more maintenance and lacks the level of refinement seen in top-tier models. It is considerably heavier and its suspension does not possess the support and composure that is expected from models costing much more.

Bikes in this ‘light trail’ classification can perform with astonishing potency, but they rely far more on weight and efficiency than more downhill-oriented platforms. A rider looking to purchase the Comp Alloy would have to accept the climbing deficit added by its overall heft in addition to the ceiling on its downhill potential due to the shorter travel and component spec. Despite this consideration, the ceiling imposed on its performance was quite high.

In comparison, the S-Works model was equally impressive but matched the goal of being a true distance hound. Despite the hub, the S-Works model was nearly flawless in its intentions. The efficiency was palpable. The power delivery was immediate but short of being racy. The drivetrain was almost impossibly effortless and light, while being solid and rugged at the same time. The suspension was massively adjustable, allowing us to dial the bike’s ride character precisely. Lastly, the SWAT door was just icing on the cake, allowing us to load up the downtube with both tools and tasty treats. These refinements didn’t always make for a faster bike, but they did make for a more convenient one. Both up and down, the S-Works has its limits, but they are perfectly reasonable considering what this bike is designed for. These attributes led us to grab the S-Works time and time again over many different bikes.

...with either bike, you will get to see nature and enjoy your time with friends.

The deciding factor here is what your time is worth to you. Can you afford AXS but choose to use a mechanical drive train because you like to take the time to precisely cut and adjust cables? Do you love the art of building your wheels? Do you care how long it takes to get from point A to point B on a ride? Those questions are in line with the differences between these two bikes. The S-Works gets from point A to point B faster, it requires less maintenance, and the refinements require less thought. But, with either bike, you will get to see nature and enjoy your time with friends.

We will agree with anyone that $3,400 is a lot of money to spend on anything, especially a bike such as the Specialized Stumpjumper Comp Alloy. We loved our time on the Comp Alloy, and we would recommend it to anyone that fits its intentions. The ride quality was awesome, and the geometry was fantastic. It was quite a battle between these two models and we believe that the Comp Alloy held its own admirably.

TLDR

Both bikes were very fun to ride. The S-Works was faster, but the Comp Alloy held its own. The Comp Alloy was especially good on wide-open trails. The S-works model required next to no maintenance. The Comp Alloy was less reliable; the wheels and drivetrain demanded more time fussing and less time riding. Considering the price, we would like for the Comp Alloy model to go a little further in terms of reducing maintenance (different drivetrain). Considering the excellent suspension and on trail feel, we think a person willing to spend more than what is considered a  ‘budget’ bike will be quite pleased with the Comp Alloy.

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About The Reviewer

Greg Montgomery - Age: 30// Years Riding: 20 // Height: 5'11" (1.8m) // Weight: 150-pounds (68kg)

When he's not winning pro-level trail running races, Greg is hammering the trails of Idaho and the Rocky Mountain region on his mountain bike. Fit, fast and knowledgeable, he's also a mechanic for his friends, where he gets his hands on all kinds of different cycling products. For fun, he'll pedal his regular bike up moto trails, keeping up with his friends on e-bikes.