Over the past decade, gravel bikes have evolved from modified cyclocross machines into purpose-built adventure platforms. Specialized has been at the forefront of this evolution, and their latest Diverge 4 represents a significant step forward.

The American brand has taken everything they’ve learned from years of road racing pedigree and off-road development, to create what they’re calling their most capable gravel bike yet. With the Diverge 4 Comp Alloy, Specialized brings advanced technology to a more accessible price point, making this an intriguing proposition for riders who want performance without the carbon premium.

Frame, Components and Groupset

The Diverge 4 Comp Alloy features Specialized’s E5 Premium Aluminium frame, which marks a significant milestone as the first alloy gravel bike ever to include integrated downtube storage. The frame shares the same progressive geometry as its carbon sibling, with a 71-degree head tube angle (in a 56cm) that prioritises stability over razor sharp handling. This slacker geometry, combined with longer chainstays (extended by 5mm from the previous generation), creates a planted, confidence- inspiring feel when the terrain gets rough.

The geometry tweaks are noticeable. Specialized has increased the reach across all sizes while dropping the bottom bracket by 5mm. This puts you deeper ‘in’ the bike rather than perched on top of it, which enhances stability when running the larger tyres this bike is designed around. The longer wheelbase means you’ll want to run a shorter stem to keep the handling responsive, and the bike comes specced accordingly.

One of the standout features is the SWAT 3.0 internal storage system integrated into the downtube. This clever design, borrowed from Specialized’s Stumpjumper mountain bike, provides genuine utility without external clutter. You can stash tubes, tools, a jacket and nutrition inside the frame, keeping the weight low and centred. The door mechanism is simple and secure, though not quite as refined as the SWAT 4.0 system found on the carbon models.

At the front, the Future Shock 3.1 suspension system delivers 20mm of hydraulically damped travel positioned above the head tube. This is spring-based rather than the adjustable hydraulic dampening found on higher spec models, but it’s tunable via three different spring rates. The system aims to absorb bigger hits while maintaining the bike’s responsiveness, though results may vary depending on your weight and riding style.

The bike rolls on DT Swiss G540 wheels, which feature 24mm internal width tubeless ready rims. These are solid, dependable hoops that won’t win any weight contests but should prove durable for long term adventure riding. They’re laced with Specialized Tracer 700x45c tyres, which is an interesting choice given the frame’s 50mm tyre clearance. While capable rubber, the relatively conservative width left me wanting more, especially given the bike’s adventure-ready geometry.

The drivetrain is where things get interesting. The Diverge 4 Comp Alloy comes equipped with SRAM Apex Eagle 1×12 mechanical shifting, featuring a 30-tooth chainring paired with an 11-50 tooth cassette. This massive range provides ample gearing for both steep climbs and fast descents, though the large jumps between cogs can feel a bit clunky compared to tighter ratios. The mechanical shifting is crisp and reliable, and SRAM’s Apex hydraulic disc brakes provide plenty of stopping power with 160mm rotors front and rear.

One welcome addition is SRAM’s Universal Derailleur Hanger (UDH), which finally makes its debut on the Diverge. This standardized system means no more hunting for proprietary hangers when you’re far from home. You can also upgrade the groupset to any available on the market, at a later date.

Riding

I’ll be honest, when I first swung my leg over the Diverge 4 Comp Alloy, I wasn’t immediately smitten. The aluminium frame, while well-constructed, has a different character than the carbon and steel bikes I’ve been riding lately. Where carbon often provides a lively, responsive feel, the alloy Diverge feels more workmanlike and sturdier. It’s capable, certainly, but there’s a muted quality to the ride that took some getting used to.

The geometry is very much focused on all-road and off-road capability rather than pure speed. That slacker head angle and longer wheelbase create a bike that feels planted and secure on rough terrain but can feel a touch sluggish when you’re trying to accelerate super hard on sealed roads. There’s a noticeable absence of that immediate response you get from race-oriented machines. When you stand up and sprint, the frame does its job, but you can feel the weight and flex that comes with aluminium construction.

That said, once I adjusted my expectations and rode the bike for what it is – an off-road endurance machine – things started to click. The compliance is genuinely impressive, even with the 45mm tyres. The bike doesn’t lack stability, and it tracks well through rough terrain. The combination of the Future Shock up front and the Roval Terra carbon seatpost at the rear does an admirable job of smoothing out rough gravel roads and farm tracks. On extended rides over corrugated surfaces, I arrived far less fatigued than I would have on a rigid bike. This was especially true on a recent trip to Dunedin with most rides going over the three hour mark.

The Future Shock 3.1 system works well, though it’s not as transformative as Specialized’s marketing might suggest. Yes, it absorbs larger bumps and reduces hand fatigue, but I found myself more aware of it in certain situations, particularly when standing to climb. There’s a subtle bobbing sensation that never quite disappears and, on very technical sections, I occasionally wished for a more direct connection to the front wheel. However, the system is genuinely useful on long gravel descents, where it helps you maintain control over sustained rough terrain. The tyres, while decent, feel like a missed opportunity. Specialized has given this bike 50mm of clearance, with space for up to 2.2 inch mountain bike tyres, yet they’ve specced relatively conservative 45mm rubber. I’d have liked to see the bike arrive with 50mm tyres to better match the geometry and truly showcase the bike’s capabilities. Running wider rubber would also help with the occasional pedal strikes I experienced on technical terrain, a byproduct of the lowered bottom bracket.

Where the Diverge 4 Comp Alloy really shines is on long, varied rides that mix sealed roads, gravel and light trails. The bike is supremely comfortable over extended distances, and the stable handling means you can maintain pace on rough descents without white knuckling the bars. It’s not the fastest bike up climbs, and it won’t win any crits, but for adventure riding and exploring back roads, it’s very competent.

The SWAT storage proved genuinely useful for stashing things on longer rides. Being able to carry essentials inside the frame rather than in jersey pockets or a saddle bag is liberating, and the low, centred weight distribution is noticeable when cornering. It’s one of those features that seems like a gimmick until you use it regularly, at which point it becomes indispensable.

The Specialized Diverge 4 Comp Alloy provides accessible, comfortable, capable gravel performance without requiring a second mortgage. And with the cost-of-living crisis, that’s a bloody good thing! However, the alloy frame’s lack of response is noticeable, particularly if you’re coming from carbon or you like to ride aggressively. This is an off-road endurance bike through and through, not a gravel racer masquerading as an adventure rig. It’s sometimes a bit sluggish when you want to push the pace, and the weight is ever-present on longer climbs. In saying that, you can switch out to a higher end carbon model and that will shed some weight and offer better responsiveness. The Future Shock system works well overall, though it’s not essential for all riders, and the 3.1 version lacks the adjustability of higher models.

For riders who want a durable, comfortable bike that can handle long gravel adventures, light touring, and varied terrain, the Diverge 4 Comp Alloy is a solid choice. It’s well-built, practical, and capable. The E5 aluminium frame may lack the zip of carbon, but it’s tough and dependable, and the inclusive price point makes advanced features like Future Shock and SWAT accessible to more riders. Plus, with it being alloy you won’t be too precious about it on those off-road adventures. Especially when laden with bags, scraping through bush and being thrown into bike boxes.

I suppose it comes down to the kind of riding you do. If you prioritise comfort and capability over outright speed, and you value practical features like integrated storage and massive tyre clearance, this bike has a lot to offer. But if you want a responsive, lively ride that rewards aggressive riding, you might be better served by the carbon version.

The Diverge 4 Comp Alloy is a capable companion for the long haul, and excellent for all-day to multi-day all-terrain adventures. The bike is comfortable, capable and excels when the going gets tough. It’s the gateway to gravel adventures and won’t break the bloody bank!