Specialized Diverge 4 Expert AXS review: heaps of fun to ride despite one frustrating spec choice

The Diverge 4 Expert AXS is the latest gravel race/adventure platform from Specialized and features some small but key updates that bring it bang up to trend, resulting in a hugely enjoyable ride.

First released way back in 2014 with 32mm tyres and Zertz inserts for frame compliance, it’s amazing to see how far the Diverge has come in the last decade. 

The core of the bike remains the same – a more confidence-inspiring ride centred around the Future Shock damper underneath the stem – but with increased tyre clearance, subtle tweaks to the geometry, enlarged frame storage and accommodation for SRAM UDH drivetrains. 

The latest iteration of the Diverge is more a case of evolution than revolution – but it has evolved into something really fun to ride. 

The bike I tested is priced at £5,249 / $5,999.99 / AU$8,200.

• Read more: New Specialized Diverge is more off-road ready than ever – but there's no top-spec S-Works version 

Specialized Diverge 4 frame

The frame of the new Diverge 4 comes in two iterations; an E5 alloy version and a FACT 9r carbon model. Those of you more familiar with Specialized’s product lines will notice the omission of the top-tier S-Works frameset. 

Fact 9r carbon has previously been reserved for the lower-priced carbon models – and upgraded to 10r, 11r and, in some cases, 12r when you move up through the ranges.

I tested the mid-level Diverge 4 Expert AXS. This has a 9r carbon frame with the Future Shock 3.2 suspension. It omits the adjustable lockout found on Future Shock 3.3, which features on the higher-end Pro and Pro LTD models.

I’ve never ridden a bike with Future Shock before, and while I didn’t find it as bobby or wallowy as I anticipated, I can’t say I noticed a massive difference in front-end comfort either. 

I used the midweight spring (Specialized ships the Diverge with light, medium and hard springs that adjust the rebound based on rider weight and ride preference), but it wasn’t groundbreakingly more comfortable than simply running an appropriate tyre pressure. 

I would have liked to see the adjustable Future Shock used here, because it would have made it easier to isolate how much compliance the system is offering, but that’s reserved for the Pro and Pro LTD builds – which feels a bit tight on a bike costing more than £5,000.

On my own gravel bike (a 54cm Specialized Crux), I run 50mm tyres with inserts, and typically pretty low pressures; so I know front-end comfort is something that can be achieved this way.

I noticed the proprietary headset top cap, despite being tightened correctly, had a small amount of play in it, which resulted in a plastic-sounding rattle when riding on rough roads or trails. 

Shredding off-road, this sound was drowned out by the general trail noise but, on more mellow rides, it was a little bit irritating.

Elsewhere, the frame is covered in mounting points. Aside from the traditional pair inside the frame’s main triangle, there are bolts for a top tube bag, bolts for a third bottle cage underneath the bottom bracket, and three bolts on either fork leg for bottle cages or bags.

There are rack and fender mounts at the back. However, to mount a pannier rack or set of mudguards, you’ll need to purchase the seatpost clamp with threads for a rack mount, or the fender bridge that puts a bolt hole between the seatstays.

The only potential boss that’s missing, as Jack observed with the previous-generation Diverge, is at the crown of the fork where a dynamo light might be fitted. Given the slightly more race-focused angle the Diverge 4 has, though, this is forgivable. 

The frame also uses the brand’s updated SWAT 4.0 internal storage under the down tube bottle cage. Specialized claims the door is a "more robust design", and the opening is larger than previously. While my bike came without the SWAT kit – a neat tool kit that fits into a bag inside the frame – Specialized has confirmed this will be included in consumer models.

As with all new drop-bar bikes from Specialized, the Diverge continues to use a threaded bottom bracket, which I’m a big fan of.

Specialized Diverge 4 geometry

Geometry is one of the key updates to the Diverge 4. Specialized has adjusted a few dimensions to make the bike a bit longer and more stable, as well as keeping the ride characteristics riders have grown to love, while accommodating more modern tyre widths. 

I tested a size 54cm, where Specialized has slackened the head tube angle by 0.75 degrees, which in turn has lengthened the trail and increased the length of the wheelbase. 

At the rear of the bike, the chainstays have been lengthened by 5mm to 430mm – again lengthening the wheelbase, while also increasing tyre clearance. 

The reach of the bike has been lengthened slightly, too. The 54cm frame sees a 4mm increase, while the 56cm has increased by 8mm, the 58cm by 11mm and the 61cm by 15mm. 

Specialized says this change has been “informed by learnings from mountain bike geometry” and that by pairing a longer top tube with a shorter stem, it can achieve a more stable ride by preventing the rider's weight being pulled further over the front wheel by a longer stem. 

All of this meant my 54cm test bike came with a stubby 80mm stem. This resulted in quick and responsive handling that, when paired with the lengthened wheelbase, made for a confidence-inspiring ride. 

Specialized has also dropped the BB by 5mm to keep the geometry consistent when opting for wider tyres. The frame itself officially fits a 50mm tyre with 7mm clearance, and a 2.2in tyre with 4mm clearance. 

This is a good thing, and keeps the bike futureproofed as more and more gravel riders opt for wider rubber. However, the tyres that came specced left me scratching my head a little.

Specialized Diverge 4 specification

The spec headlines for my test bike are that it uses a SRAM Rival AXS Transmission 13-speed groupset, a set of Roval Terra carbon wheels shod with Specialized’s own Tracer tyres, and alloy finishing kit from the brand's own stable. 

The Rival AXS groupset is excellent. It performed faultlessly throughout testing. The shifter ergonomics are great – with a slightly longer reach and a hood shape that I find quite similar to Shimano’s GRX Di2 shifters. 

The gear ratios are well thought-out for a bike of this type. The 10-46t 13-speed cassette, paired with a 40t chainring, gave me plenty of top- and bottom-end range, and didn’t have any hugely noticeable jumps.

I ragged the bike through some thick undergrowth – with pretty solid twigs and the like pulling at the drivetrain – but the UDH system proved rock-solid; no more bent derailleur hangers here. 

The wheels are a good pairing for this bike. The Roval Terra C rims are a gravel-specific model with a 25mm internal width. Laced with J-Bend DT Swiss competition spokes to a DT Swiss 370 hub, they’re a solid choice and easily serviceable if you break a spoke or need to true a wheel.

Now, onto the tyres; my major gripe about this bike. 

Specialized has specced its new Terra gravel tyres. The tread is versatile without feeling sluggish, they’re a competitive weight and they look great with the tan sidewalls. 

Despite being available in a 50mm width, Specialized has opted to fit a 45mm tyre to the Diverge. 

It seems like a bit of a miss to me that Specialized would boost the tyre clearance on the new Diverge only to then not spec a bigger tyre. The tyres themselves are really nice, and pretty good value at only £45 – but to get the most out of this bike, I’d swap them out for a wider set of gravel tyres straightaway.

45mm is not narrow by anyone’s standard. However, the updated geometry of the Diverge 4 – with a lower BB to accommodate a bigger tyre, paired with a 45mm tyre width – means the ride height is pretty low. 

The 54cm model came with 172.5mm cranks; longer than I would like, but not out of spec for a bike of this size – and I was clipping my pedals on even pretty mellow trails with the low-slung bottom bracket.

Cranking over bigger roots and rocks without preemptively balancing my pedals would send the back end of the bike up in the air, and leaning over even slightly around off-road pedalable corners had me grounding the pedals, too.

Another spec misstep – albeit a more forgivable one – is the choice of saddle. The bike comes with a Power Expert saddle, a seat that was originally designed for aggressive road-racing setups, where soft-tissue pressure was of key concern to riders looking to ride with a large saddle-to-bar drop. 

The Diverge has a pretty relaxed geometry, so I found the Power an odd spec choice. When I sat on the saddle in a more upright position, I couldn’t quite find a comfortable spot, so slid around a lot while I was riding. 

However, saddles are a hugely personal thing and you might find the Power to be the perfect choice for this bike. Rear-end comfort, in general, was not a problem thanks to the carbon Terra seatpost – with flexion adequate to absorb road noise and bumps.

The handlebar is Specialized’s own alloy Adventure Gear Hover bar, with a 12-degree flare and a 20mm rise to the tops. This rise definitely felt unnecessary given the stack height of the bike, and I’d have liked a more traditional flat top section but, again, this largely comes down to a personal fit preference.

Specialized Diverge 4 ride impressions

The new Diverge is really fun to ride. My test rides covered flat and smooth gravel, some pretty steep and loose climbs, and some pretty chunky singletrack that is perhaps better suited to a mountain bike. I know all of these trails really well, and have ridden them plenty of times on heaps of different bikes – from my CX setup with 33mm tyres, right the way through to my hardtail MTB with 2.35in tyres.

Of course, these trails were threaded together by roads but, as with most places in the UK, a lot of these roads would probably pass for light gravel in places with a higher standard of tarmac.

The updated geometry that increases the trail of the fork certainly inspires confidence on steeper, loose terrain. It was really pleasant to settle into the Diverge and throw it down some technical trails I know well. 

While it took me a while to get used to the more upright position when cruising along at a steady pace, as soon as I started to push on some singletrack, the position and geometry made sense.

The longer top tube, paired with a shorter stem, made for really responsive handling while maintaining a stable ride that didn’t feel sluggish or wallowy. I went into the test ride assuming the shorter stem would make the bike really twitchy, but I didn’t find this to be the case. 

Although I couldn’t tangibly feel the Future Shock absorbing bumps (wide tyres at lower pressures have much more impact, in my experience), I have no doubt it went some of the way to keeping the front of the bike stable when chattering over loose surfaces. 

Some of the trails I tackled are definitely better suited to mountain biking, but the Diverge more than held its own in such challenging terrain.

The bike was responsive and flickable on technical trails, while maintaining stability when cruising on roads or more mellow gravel.

I was able to hop between tyre tracks on some of the farm tracks I rode on and – when climbing steep, slow, technical off-road climbs – I didn’t find the front end floating. I was able to winch up almost anything, unless my cranks ground out on a rock, root or step, of course.

Specialized Diverge 4 bottom line

I really enjoyed my time testing the Diverge, but I wish Specialized had made the most of its increased tyre clearance when speccing the bike. This would solve the issue I had with clipping my pedals, while also enabling me to get much more out of the bike as it’s intended to be used.

The build on this model is really great, and the new Rival AXS groupset performed flawlessly, which is even more satisfying when you consider that this Expert build is £250 less expensive than the previous model. 

However, the previous iteration of the Expert model included the adjustable previous-generation Future Shock – which I think would be a notable upgrade over the non-adjustable version.

Value-wise, this is still a relatively expensive proposition, and competitors are offering more for less. Canyon, for example, has its Grail CF SLX 8 AXS priced at £5,149, and that features SRAM’s next-tier-up Force groupset and a power meter. It’s nice to see Specialized bring its prices down a bit from previous model years, but it has a way to go yet for ultimate value.

Overall, the Diverge 4 is a really fun bike that feels equally at home on technical singletrack as wide-open gravel roads. Specialized says this is the perfect bike for gravel racing, adventure riding and bikepacking, and I’d say that’s pretty much on the money, even if there are spec and value question marks.