New Specialized Diverge 4 receives several key updates, but the alloy models have something never seen before

While the Specialized Crux remains the lightweight gravel racer (and cyclocross bike, let’s not forget) in the brand’s lineup, the Diverge has become the de facto machine of choice for its gravel pros, and the most popular option for amateurs and casualists too thanks to an extensive lineup of carbon and alloy models.

Today the Californian giant has updated the Diverge platform with the new Specialized Diverge 4, firmly aimed at taking on the best gravel bikes on the market today, and while at a glance the new model looks strikingly similar to the outgoing one – we first saw it in action at Unbound this year – there are some significant tweaks that bring it up to date with current gravel sensibilities for both gravel racing and more adventure style riding.

Tyres now measured in inches

Gravel tyres are getting wider, a trend that’s been unstoppable since gravel came into being. We’ve proven in our own lab tests that wider tyres are faster, and now that racers are more than ever looking to mountain bike tyres for an extra performance advantage Specialized has upped the clearance on the Diverge 4 to 50mm, with 7mm of clearance around the tyre.

It does also say that a 2.2” tyre will fit with 4mm of space around it, though riders should be aware that this is going to impact the space for mud. In any case, this is what we expect most racers will opt for. It's not the largest on the market, but it's up there with the best.

In order to achieve this there is a new fork, which is relatively easy from a design standpoint. At the rear end however the geometry has had to be tweaked to compensate, with a 5mm longer chainstay length to move the rear tyre away from the seat tube. To make the chainstays wide enough that the tyre would fit Specialized used a solid section of carbon on the drive side, where it also has to clear the chainring, with the brake hose and cables routed through the chainstay protector. On the alloy models a similar system has been devised but via the use of a cast alloy yoke that’s then welded to the tubes.

Futureshock 3.0

The increased tyre volume will increase comfort over rough terrain, and in a similar vein the Diverge 4 retains the Futureshock system, but upgrades it to the Futureshock 3.0 also found on the Specialized Roubaix SL8. This provides 20mm of travel at the front end, damped by hydraulics and tuneable with a knob atop the stem where the top cap would usually reside.

Specialized claims that it offers a 53% reduction in ‘peak impact’ and an 11 watt saving over rough gravel versus an unnamed competitor machine. Given the wattage savings on offer that we found in our lab testing of larger tyres over rough ground we can see how this could be possible.

To complement this the Roval Terra seatpost, also found on the Diverge 3, is in evidence again, offering a claimed 18mm of rearward travel for a hair under 200g.

More storage

While bigger tyres is an almost universal trend, downtube storage is less of a ubiquitous feature on modern gravel bikes. Nevertheless, the Diverge 4 builds on the SWAT storage in the downtube of the outgoing model by increasing the capacity by 5% and the door size by 10%. There exists, in Specialized’ words, “no gravel bike with a greater combination of storage capacity and tyre clearance”, though tyre size multiplied by cubic inches of storage has yet to catch on as a common metric in the bike industry.

While downtube storage is common on carbon bikes, the alloy versions of the Diverge 4 are groundbreaking in that they are the first alloy bikes to come with storage within the frame. Within either it should, according to Specialized, be possible to fit a jacket, 2 tubes (presumed TPU), plug kit, tyre boot, tyre levers, multi tool, 2x C0₂ or a mini pump or a battery inflator, car keys (because you’ve driven to your gravel ride) and 6x gels.

Geometry tweaks

As well as the longer chainstays to accommodate the larger tyres, the frame has been tweaked to make it longer and slacker, with the aim of greater capability over rougher, more technical terrain. The head tube is 0.75 degrees slacker, and the reach made longer to account for this. Combined with the longer chainstays the wheelbase will now be longer.

The bottom bracket has also been lowered by 5mm in order to offset the additional ride height from running larger tyres. The frame itself tips the scales at 1150g/2.5lbs, with full builds ranging from 8.01kg/17.7lbs in top spec through to 10.7kg/23.6lbs for the lowest spec alloy model.

Pricing information has not been provided at this stage.