2021 Specialized Diverge Expert Carbon review: A curious take on gravel geometry

2021 Specialized Diverge Expert Carbon review: A curious take on gravel geometry

The latest generation of Specialized’s Diverge carbon gravel bikes has undergone a dramatic transformation from the one that came before, and while the new Future Shock 2.0 suspension unit has garnered much of the attention, it’s the revamped frame geometry that truly defines the new bike’s personality. The 2021 Diverge looks sleeker and is arguably more road bike-like in its appearance than before, but in reality, it handles more like a mountain bike — and not everyone is going to like it.

Story Highlights

  • What it is: The latest generation of Specialized’s dedicated gravel bike.
  • Frame features: Carbon fiber construction, clearance for 700×47 mm or 650×53 mm tires, six bottle mounts, threaded bottom bracket, integrated storage.
  • Weight: 1,100 g (claimed weight, 56 cm frame only); 9.18 kg (20.24 lb, 52 cm size, actual weight, without pedals or accessories)
  • Price: US$4,800 / AU$7,500 / £4,500 / €5,000
  • Highs: Fantastic ride quality, confidence-inspiring stability, excellent tire clearance, handy SWAT down tube storage.
  • Lows: Nearly non-existent suspension tuneability, polarizing frame geometry and aesthetics.

A dramatic left turn

Specialized certainly could have gone the safe route in redesigning its popular Diverge range of gravel bikes, with a bit more tire clearance, some slight adjustments in head tube angle and bottom bracket height, maybe a few additional mounts — and, of course, the usual updated colors and graphics. However, this new Diverge is a very different machine to the one it replaces, and is perhaps indicative of where Specialized sees the gravel category moving in the years to come.

Hint: further off-road.

Instead of trying to make the new Diverge handle more like a road bike (perhaps as a way to sooth the worries of converted roadies making the migration away from tarmac), the frame geometry more closely mimics that of mountain bikes in a few key areas.

The geometry is a big departure from gravel bike norms, featuring a longer top tube, a shorter stem, a slacker head tube angle, and a longer front center and wheelbase.

Reach dimensions have increased across the board, albeit not by a tremendous amount. On the 56 cm size, for example, it’s only grown by a fairly modest 7 mm, which hardly takes the Diverge into hyper-progressive territory. The head tube angle has slackened by 0.75º on that same size, though, and when combined with the generous 55 mm fork rake that’s shared for all frame sizes, the front wheel is now a substantial 26 mm further ahead of the bottom bracket than it used to be.

Things have grown longer out back as well, with chainstays now measuring 425 mm across the board — a gain of 5 mm. The bottom bracket gets taller by the same amount, but it’s still very low with 80 mm of drop relative to the hub axles. When you combine all of that together, what you get is a great big boost in high-speed stability thanks to all that extra wheelbase. Stem lengths have gotten a fair bit shorter, too.

Stem lengths are fairly short across the board, although interestingly enough, Specialized also varies stem length with particular models of Diverge, too.

Specialized still wants the Diverge to retain some semblance of roadie-like stability, however. Although that head tube angle is more relaxed than before, the 71.25º figure on the 56 cm size is still almost 5º steeper than what Evil uses on its ultra-progressive Chamois Hagar, and its 57 mm trail dimension is not only essentially unchanged from the previous Diverge, but also well within the range of what you’d expect on a traditional endurance road bike (the Chamois Hagar’s trail, meanwhile, is a whopping 93 mm).

But also more of what you’d expect

The Diverge’s dramatic geometry changes may be somewhat surprising, but other aspects of the redo are wholly expected.

Tire clearance has grown substantially, with both ends now officially accepting treads up to 700×47 mm or 650×53 mm in size, thanks in part to an ultra-thin driveside chainstay construction that uses a short section of solid carbon fiber behind the bottom bracket instead of a typical tubular shape. As a nice bonus, the new Diverge retains compatibility with both 1x and 2x drivetrains while also looking refreshingly normal with not a single droopy tube in sight.

Instead of dropping the chainstay as is becoming more common these days, Specialized just made the chainstay section a lot thinner.

Going along with the higher speeds that the lengthier frame geometry and larger potential tire sizes allow, the front flat-mount disc-brake mounting holes are positioned for 160 mm or 180 mm-diameter rotors instead of the usual 140 mm or 160 mm ones. 160 mm rotors are stock, but it’s nice to see there’s room to go up if you feel the need.

Additionally, there’s more versatility and capability on tap. Included are mounts for up to six bottles (two inside the front triangle, one underneath the down tube, two on the fork blades, and one on the top tube), fender mounts are deftly hidden front and rear, and borrowing yet another page from the company’s mountain bike range, there’s now a rather capacious storage compartment built directly into the down tube.

More of an emphasis on ride quality, too

First introduced on the latest Roubaix endurance road bike, Specialized’s newer Future Shock 2.0 suspension cartridge now finds its way into this latest Diverge, once again occupying the space between the top of the cut-off steerer tube and the base of the stem. Travel is still limited to a modest 20 mm courtesy of a steel coil spring and a series of roller bearings. However, there’s now an oil damper to lessen the bounciness of the old design, and the compression circuit is adjustable on the fly all the way up to a locked-out position for when you’re riding exclusively on smoother surfaces.

Out back, Specialized relies on a more tried-and-true concept. On the previous-generation Diverge, Specialized left a lot of the heavy lifting in terms of rear-end comfort to the goofy CG-R carbon fiber seatpost with its pseudo-flex head and elastomeric insert. With this new Diverge, Specialized did away with all of that, instead just sloping the top tube more and exposing more seatpost.

So how well does it all actually work?

Most bike reviews here on CyclingTips usually only include the viewpoint of a single rider, on a single bike. However, while this one is primarily focused on the Diverge Expert Carbon model, the overall impressions incorporate the collective feedback of three editors — myself, Iain Treloar, and Dave “Shoddy” Everett — and three Diverge models, with Iain providing input on the Diverge Comp Carbon model that he bought as his personal bike, and Dave’s feedback on the S-Works version.

The Diverge Expert Carbon features the second-tier frame with Shimano’s 1x GRX Di2 groupset.

The Diverge Expert Carbon model is built with Specialized’s second-tier FACT 9r carbon frame, a Shimano GRX Di2 1×11 electronic groupset with a Shimano Deore XT 11-42T cassette, and modest DT Swiss G540 tubeless aluminum rims laced with DT Swiss 14 g straight stainless steel spokes to Specialized house-brand hubs and wrapped with 700×38 mm Specialized Pathfinder Pro tires. With the tires setup tubeless, my 52 cm sample weighs in at 9.18 kg (20.24 lb), without pedals or accessories. Retail price is US$4,800 / AU$7,500 / £4,500 / €5,000.

Over in Melbourne, Iain’s Diverge Comp Carbon features the same carbon frameset and wheel-and-tire package, but a 2×11 Shimano GRX mechanical groupset. Actual weight for his 56 cm bike is 9.95 kg (21.94 lb), also without pedals or accessories. Retail price is US$3,800 / AU$5,800 / £3,400 / €3,800.

And as for Dave’s S-Works model … well, suffice to say it’s the lightest and most luxuriously outfitted, built around the 100 g-lighter FACT 11r frame, a SRAM Red eTap AXS 1×12 wireless groupset, Roval Terra CLX carbon wheels, and an X-Fusion Manic dropper seatpost. Dave unfortunately didn’t get a weight for the one he rode, but with a retail price of US$10,000 / AU$16,000 / £8,900 / €NA, let’s just assume it’s pretty light.

Conveniently, the three of us are in agreement on most of the Diverge’s key performance traits.

Although 20 mm of travel doesn’t sound like much, the Future Shock 2.0’s hydraulic damper makes for a much more composed and capable feel than previous versions, which were bouncier and less controlled. In the fully open setting, the Future Shock 2.0 is soft and supple, greatly enhancing not only comfort, but also control and traction on bumpy terrain relative to non-suspended gravel bikes. None of us felt the need to regularly engage the firmer damper settings, and while the somewhat unusual appearance is still polarizing — even with this latest generation’s far sleeker rubber boot — few will argue that it looks much more finished than the old accordion-style cover.

“It doesn’t give a perceptible bob unless out of the saddle, and even then, it’s not enough to bother me,” Iain said. “On the rocky fireroads and rough singletrack that I mostly ride this bike on, it’s outstanding having a bit of extra give at the front end, and I feel much less beaten up in the shoulders than on other gravel bikes I’ve used (most recently including the Parlee Chebacco). It gives me some of the sense of off-road confidence I got on the Cannondale Slate, but in a lighter, less oddball package. It looks far better than the previous generation Future Shock, too.”

The overall ride quality front-to-back is also impressively balanced. Seated, the Diverge is absolutely superb, with all that seatpost extension serving up plenty of comfort-boosting flex when you’re on rougher terrain. Most of that cushiness goes away when standing, of course, but the rear end of this latest Diverge is still far from harsh. It’s important to note, however, that the silky seated comfort largely disappears if you add the dropper post, what with its thicker-walled aluminum construction. Add it if you must, but do so with the understanding that the bike won’t ride nearly as well as it could.

Lots of exposed seatpost translates to lots of rear-end comfort.

Interestingly, neither of us were bothered much by the Diverge’s tall stack height — a consequence of adding 20 mm of suspension movement. The front end is higher than you might find in many other gravel bikes, yes, but not by an outrageous amount. And if anything, the taller bar position forces you to use the drops more often, where you have more steering and brake control, anyway. Still think it might be too tall? Our suggestion would be to ride it first.

Stiffness-wise, we weren’t blown away by the Diverge’s snappiness. It’s hardly soft and spongy, but nor is it especially taut and explosive when you start smashing the pedals. That said, none of us saw it as a significant downside, particularly given the genre. We are talking about gravel bikes here, after all, and there’s a strong argument to be made that sacrificing a bit of bottom bracket stiffness (and, presumably, some pedaling efficiency) in favor of rider comfort is a more effective way of increasing overall performance on anything other than perfectly smooth tarmac.

A stiff frame sounds great on paper, but on rougher ground, it’s more important that you’re able to keep putting down power, and Specialized has done an excellent job on that front.

Some smaller details left a positive impression, too.

I’ve had ample prior experience with Specialized’s clever down tube storage compartment, and fully anticipated its usefulness. In addition to a flat repair kit, I regularly stuffed a light jacket, one or two gel packs, and occasionally some arm or knee warmers in there (and yes, it all fits just fine). It was more of a revelation for Iain and Dave being their first experience with the concept, but it didn’t take long before they were fans as well.

“Initially I was inclined to write off the SWAT storage as a gimmick, but I’ve come to really love it and wish for something like it on every one of my bikes,” Iain said. “It’s rattle-free, secure, and clean-looking.”

Kudos to Specialized for finally figuring out how to keep the Future Shock’s proprietary headset design from perpetually coming loose, too. The system still comprises two pairs of small grub screws — one pair for adjustment, the other to lock things in — but you can now actually tighten them against each other thanks to flats that are built into the lower screws. The whole process is still a little fiddly (and those lower bolts require a dedicated wrench), but it at least works the way it should. Better late than never.

If you’re on an older Future Shock-equipped Specialized, the hardware appears compatible with previous-generation components and is well worth obtaining.

Handling quirks

Our opinions were a little more mixed in terms of how we found the revamped frame geometry.

“I’m impressed with how well it rides across different tyre sizes,” Iain said. “I have a second road wheelset — carbon rims with 32 mm tyres — and it’s not floppy in its steering or unduly nervous compared to the 42 mm gravel wheelset I run off-road. It’s stable but responsive, and I find it fun and accommodating when I’m riding it on terrain at the rougher end. I can’t say I get on it and think anything much other than, ‘this is just doing what I need it to’.”

“That short stem, longer top tube, and longer wheelbase does make for a very stable bike,” added Dave. “All around, it’s predictable, and sits very well on a multitude of surfaces.”

The new Diverge’s more MTB-inspired frame geometry certainly sets it apart from the mainstream.

As compared to a comparably sized Trek Checkpoint, the reach on the Diverge is only a few millimeters longer, but the slacker head tube angle and more generous fork rake put its front wheel more than 20 mm further in front of you. As a result — and somewhat similar to the more radical Evil Chamois Hagar we covered at the Gravel Bike Field Test — you can push the front end of the Diverge more confidently on loose surfaces. Instead of just sliding out from under you when you lose traction, the front wheel’s more likely to just harmlessly slide for a bit before catching again.

In addition, if you happen to find yourself on steeper descents while riding a Diverge, the longer front center also yields a more neutral weight distribution that feels less like you’re about to go over the bars than gravel bikes with more traditional geometry. Without question, I found myself having more fun on faster and steeper downhills than any number of more traditionally proportioned gravel bikes. As a nice bonus, toe overlap simply isn’t an issue at all.

In that sense, the Diverge’s front-end geometry is a big hit for me. Not coincidentally, it’s one of the traits I like most about modern mountain bikes.

That said, I’m not sure that the concept works as well for all-purpose gravel riding as it does on mountain bikes.

In the mountain bike world, that longer front center is usually also paired with a very slack head tube angle, a stubby sub-50 mm stem, and wider handlebars that rarely measure narrower than 760 mm. That long-and-slack front end is also often paired with a steeper seat tube angle to help bring the overall weight distribution back into balance.

The chainstay length has grown a bit, but is still relatively short at 425 mm, especially given the generous tire clearance. Bottom bracket height has gone up 5 mm, but it’s still quite low with 80 mm of drop.

In a vacuum, you’d expect the generous trail dimension that results on those modern mountain bikes — it’s over 100 mm even on Specialized’s new, and very XC racing-focused, S-Works Epic — to yield a super floppy-feeling front end that’s slow and cumbersome through tight corners. However, the short stem reduces the amount of physical movement required to initiate turns, while the wider bar keeps the front wheel from just falling over to either side. Basically, it’s the combination of all those factors that makes it work, and removing any one of them takes away from the magic.

The Diverge includes that somewhat slack head tube angle, the longer front center, and a somewhat shorter-than-average stem (90 mm on a 56 cm frame), but it still uses a road bike-like trail dimension that ranges from 57 to 69 mm, depending on size. As a result, you get the stability of that overall longer wheelbase at medium-to-high speeds. But with that shorter stem, modified weight balance, and quicker trail dimension, I found the front end to be more prone to wandering off-line on slower and/or steeper climbs. And yet despite the steering quickness, I occasionally still had to shift my weight more aggressively forward to get the front end to bite.

One thing to note: Specialized alters the stock stem length depending on the model. On my 52 cm Diverge Expert Carbon, the stock stem length is just 70 mm (which contributes to the slow-speed wandering). But on the S-Works model, it’s a more normal 90 mm. Indeed, when I swapped to a longer stem, a lot – but not all – of the bike’s handling quirks went away.

Overall, Specialized is clearly pushing some boundaries with the Diverge’s handling, but the result strays sufficiently far away from the norm that there’s plenty of potential for it to be divisive. Is it bad? I wouldn’t say so, and Iain and Dave obviously got on with it just fine. That said, the overall handling traits are definitely atypical, and I think a test ride would be even more important here than usual. Just be sure to keep the stem length in mind, too.

Future Shock at the fringes

Our viewpoints of the Future Shock 2.0 also start to stray a bit, at least when the bike is pushed to its limits.

For sure, it does a very good job of squelching high-frequency vibrations and smaller chatter on dirt and gravel roads, and even tamer sections of singletrack. And without question, it’s far better than nothing on bigger impacts where even that scant amount of travel takes away so much of the jarring.

“The suspension isn’t all that subtle if it’s getting hammered,” Iain professed. “I don’t mind it because it lets me bulldoze over things and I’m not exactly riding with all that much finesse, but I can see that some more nuanced tastes could recognize that as a problem. From a road rider’s perspective or someone who’s got less experience of what good suspension can feel like, I think a lot of riders would just be stoked to have a bit of cush.”

Specialized packs quite a bit into the Future Shock cartridge, but I’d argue that it could still use some more.

I guess that means my tastes are nuanced, because as good as I think the Future Shock 2.0 has gotten, my mountain bike background also couldn’t help but see some of its deficiencies.

I’ve long been a proponent of the quality of travel being more important than the quantity, and in my opinion, that becomes even more critical when you don’t have much travel to play with. If you’re in the bell curve of rider shapes and sizes — and in the bell curve for how people will likely ride this bike — the Future Shock 2.0 will probably be fine.

However, it’s a major fail in my book that Specialized equips every Future Shock 2.0 cartridge with the same spring rate, regardless of rider weight or position, stem length, or handlebar drop.

“Future Shock 2.0 uses the same main spring rate across all sizes,” confirmed Specialized global road marketing operations manager Kelly Henningsen. “Our Future Shock field testing has not shown much correlation between rider weight or bike size and desired spring rate, especially once we’ve added the damper with Future Shock 2.0.”

Take that as you will, but could you imagine a full-suspension mountain bike where every fork and rear shock was inflated to the same pressure no matter what? It’s something no one would ever consider remotely viable in the MTB world, and yet here we are with the Diverge. In addition, while the compression damping is adjustable, the rebound damping is not, meaning there are times when the front end feels like it’s recovering faster or slower than you might want it to.

It seems a little odd to me that Specialized would provide users with the option of a larger 180 mm front rotor, but yet limits every rider to the same spring inside the Future Shock cartridge.

As already mentioned, the Future Shock is pretty good as is, and likely quite a bit better than you’d think. But it’s also not as good as I think it should be, either, and in my opinion, Specialized is selling gravel riders short by assuming they wouldn’t appreciate some additional tuning options.

Spec notes

There’s not a whole lot to say about the build kit on the S-Works model given its top-shelf status. SRAM’s “mullet” wireless groupset works very well with fast and precise shifts, and it offers a generous amount of range, albeit at the expense of larger gaps between individual gears. SRAM’s disc brakes are arguably easier to control than the more “on-off” nature of Shimano’s stoppers, too, and my long-term experience with the Roval Terra CLX carbon wheels has shown them to be wonderfully lightweight and snappy, but yet impressively tough and durable as well. All that said, no real complaints here.

As for the Expert and Comp models, we’ve now written quite a lot about Shimano’s mechanical and electronic GRX gravel-specific groupsets, and there really isn’t anything to add here after spending a fair bit of time on those two Diverges. The shift quality is typically Shimano-smooth, the brakes are powerful if a bit grabbier, and both groupsets are reasonably light. I’m not a huge fan of the super-aggressive hood texture on the Di2 levers, but perhaps my hands have grown overly delicate since the end of my bike shop mechanic days. Overall, GRX has proven itself to be the gravel equivalent of the Ultegra road groupsets, which is saying a lot.

The Shimano GRX Di2 groupset on the Diverge Expert Carbon model works as expected, which is to say that it’s fast and virtually flawless.

Given the rather sizable price difference between the Diverge Comp Carbon and Expert Carbon, though, I’m not sure the Di2 transmission is worth the premium. It’s better, yes, but not that much better, and the mechanical stuff is so good that it’s hard to justify spending the extra money, especially given that both models share the same wheelset. If you have a strong preference for 1x vs. 2x drivetrains, that might very well force your hand since the Comp Carbon is the nicest model offered with two chainrings; everything above that is 1x-only (although the frames can accommodate either).

Speaking of the wheels on the Comp and Expert models, they’re rather ho-hum. The rims are impressively tough, but they’re also a little heavy, and the straight 14-gauge spokes deaden the ride quality. And should we really have house-brand hubs at this price point with generic pawl-type drivers? I’d argue no.

The stock Pathfinder Pro tires don’t help, either. Iain didn’t find them as objectionable as me, but I found the casings to be thick and lifeless, and there’s a very narrow range of inflation pressures where they don’t roll horribly slow and yet still provide decent grip.

The stock Pathfinder Pro tires are tough-wearing, but less-than-impressive in terms of rolling speed and grip. Likewise, the stock wheelset on the Expert Carbon and Comp Carbon models are average at best.

As for the flared drop bar on the Comp and Expert models with its built-in rise, it’s definitely very much a matter of personal preference. That said, neither Iain nor I fell in love with it.

“Bar and tyres aside, it’s a pretty thoughtful build that matches my personal preferences well,” Iain summarized. “And I didn’t really need to upgrade or modify things off the shelf.”

Diverging from the straight and narrow

Given how important the Diverge family is to Specialized’s bottom line, the company has certainly taken a pretty big risk by changing it so dramatically. Most of the changes are undoubtedly positive — the ride quality, the tire clearance, the aesthetics, the storage and mounts — but the handling will likely be more polarizing.

As is usually the case, Iain’s words are better than mine.

“I don’t think it’s a perfect bike, but it has fewer compromises than many others I’d considered. It’s a 7.5-8/10 bike for me; there are things I would want differently, but I also can’t think of something else on the market that would better match what I’m looking for in a gravel bike.

“To me, the Diverge is the middle ground between the gnarlier abilities of, say, a Cannondale Topstone Lefty, and something more road-leaning like a Cervelo Aspero or Parlee Chebacco. I don’t think I could happily settle for either of those extremes in a bike for my style of riding, so even if the Diverge isn’t ideal at either end it kinda straddles the two.”