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The Specialized Diverge Pro 4 makes rough gravel your playground
The Diverge Pro 4 is happiest when the road gets ugly.
When I make my yearly trip to Denver, I always bring my road bike. It’s my annual chance to suffer on the kinds of gradients unavailable in the glacier-scoured lands of northeastern Illinois. In advance of this year’s trip, Specialized hooked me up with its new gravel bike, the Diverge Pro 4, so I brought it with me to challenge it in ways not possible on the fastidiously groomed gravel trails of suburban Chicago.
In contrast to the Specialized Turbo Creo 2 we reviewed a couple of years ago, the Diverge Pro 4 is strictly human-powered. Specialized calls it “the ultimate getaway vehicle,” designed with input from off-road adventure riders, scientists, and racers. It’s marketed as the only gravel bike you need for racing, adventure, and distance rides. While I can’t speak to its racing performance, I can say the Diverge Pro 4 is a blast on any kind of gravel and does well enough on the road.
Priced at $8,249, the Diverge Pro 4 is designed for rough trails and technical descents, both of which unfolded below me at the summit of an is-it-gravel-or-is-it-single-track climb in Douglas County, Colorado. I took a deep breath, and down I went. The descent was rutted and slightly more technical than anything I’ll ever run into around Chicago, but I had enough time on the bike to realize that if I had trouble on the descent, it wouldn’t be the bike’s fault.
To understand what makes the Diverge Pro 4 stand out, I’ll start with my favorite feature. Future Shock 3.3 is Specialized’s suspension system, and it’s a significant upgrade over the earlier versions used on the Turbo Creo 2 and Diverge Pro 3. The mechanism lives between the head tube and stem. It isolates the rider from high-frequency impacts while adding relatively little weight and without changing the bike’s steering geometry or introducing brake dive—two compromises that can come with conventional suspension forks. The fork, head tube, and front wheel remain rigidly connected, with the stem and handlebars moving vertically relative to the rest of the bike.
Future Shock uses hydraulic damping to control the movement of the spring inside the head tube. A spring by itself will just compress and return the stored energy, which can lead to a pogo-stick-like experience on bumpy roads and gravel. The damper converts some of that energy into heat by forcing fluid through a controlled pathway. The result on nasty terrain is controlled vertical movement rather than a bouncy rebound. 20 mm doesn’t sound like much, especially to anyone accustomed to mountain bikes with 100 mm or more of suspension travel. But Future Shock isn’t trying to keep a wheel planted while you launch off a rock. Its job is to prevent a stream of smaller impacts from traveling through the handlebars, into your hands, arms, shoulders, and eventually your increasingly annoyed brain. And it’s very good at it.
Specialized says laboratory testing showed up to a 53 percent reduction in peak impact at the bars versus competing setups. That’s an impressively precise number generated under equally precise laboratory conditions, so don’t read it as “every bump feels 53 percent smaller.” But whatever the decrease, the underlying effect wasn’t difficult to detect, as I felt less arm and upper-body fatigue after long rides than I experience on my own gravel bike.
Compression damping can be adjusted on the fly with a dial at the top of the stem, changing how readily the system moves through its 20 mm of travel. At the firmest setting, Future Shock moves very little under normal riding loads; open it up, and the bars move much more freely over bumps. After some experimentation, I left it fully open on nearly every surface.
Specialized made a number of other changes from the Diverge Pro 3, all of which are positives in my book. The Diverge Pro 4 sports the bike maker’s mid-range FACT 9r carbon frame with reworked geometry that offers longer reach for better weight center