Cannondale Topstone Ultegra RX 2 review

Curious to see what all the fuss was about, there were a couple of times last year when I took my trusty Cannondale CAAD8 off the tarmac and onto some – admittedly tame – off-road trails. The 25mm tyres could be nothing more than nursed over the rough stuff but, even so, I’d seen enough to put my hand up when Cannondale sent a Topstone – its flagship gravel bike – in for testing. 

Image 1 of 13

Design

The model you see here is the Topstone Carbon with Shimano Ultegra RX groupset. Cannondale makes an alloy Topstone but only with the Carbon frames do you get this bike's big selling point: the Kingpin suspension system. 

Rather than using a shock and linkages, this simply involves a thru-axle pivot where the low seat stays meet the seat tube, allowing the back of the frame to flex, with claimed travel of 30mm.  

Components and build

The Ultegra RX2 model sits above the 105 version but below the electronic SRAM Force eTap AXS, and slightly below the Ultegra RX. There are actually a couple of advantages of the RX2 over RX. You get a full carbon seatpost – which seems important given the emphasis on flex and suspension at the rear – and a pricier Fabric saddle. 

However, what swings it way back the other way are the wheels. While the RX2 comes with WTB KOM light alloys, the RX – and eTap – comes with far superior Hollowgram carbon rims.

The bike comes with hydraulic disc brakes, WTB Riddler tyres, and gearing of 46/30T front rings with an 11-speed cassette (11/34T). It weighs in at 9kg.

Riding impressions

While I’ve been thoroughly impressed by the bike, it was hardly love at first sight. The frame sizes aren’t measured in centimetres but in small, medium, large, and extra-large. At 6 foot 1, on paper, I fitted pretty snugly into the ‘large’ bracket, but I quickly found the bike was too big for me. 

With the seatpost rammed all the way down, and the saddle all the way forward, it was still too high and too far back for a comfortable pedal stroke. Instead of sending it back and asking for a medium, I cut the seatpost and dropped the stem slightly, and have actually settled on a position that feels great. While I’m happy with this set-up, and everyone is different, I’d warn that the Topstone sizes up pretty big and might feel like a lot of bike.

To compound the teething problems, I had three very early punctures, two of them on the road, which has hardly left me convinced by the 37mm WTB Riddler tyres. What’s more, they’re stubborn to seat on the rim, leaving me to resort to the soap and over-inflation treatment, and asking a hell of a lot from a mini pump on-the-go.

Despite those uncomfortable early outings, the bike has won me round. Pre-coronavirus pandemic, I used it on my commute, a 25km mixture of road and cycle path and was surprised how smoothly it cruised along. It doesn’t feel zippy, and the Kingpin flex, which claims to reduce almost completely when out of the saddle, does feel a tad spongy on steep inclines. However, when it gets up to speed, it’s remarkably efficient. The geometry is definitely over at the road end of the gravel market, and so those tarmacked kilometres that link the gravel are far from a drag.

Likewise, at the other end of the spectrum, I took it onto a couple of mountain bike trails, and it coped. The 37mm tyres struggled with the larger rocks, and the drop bars soon became uncomfortable. As it is, it gets you by on the more technical terrain, but to start really riding it you’d need to at least max out the 40mm tyre clearance, if not fit 650b rims, which in turn takes that max clearance to 48mm.

But less about what it ‘can also’ do, and more about what it was born to do. On the pure gravel, the Topstone truly comes to life.

The realisation was instant. Admittedly, my past experience had been on 25mm tyres, but the ride was so smooth and so assured. The suspension system comes into its own here and it does feel like you’re floating over the rough terrain rather than ploughing through it. My first tentative foray out of the saddle turned into a full-on 200-metre sprint and the acceleration astonished me. The traction, even on the looser stuff, is remarkable, and – aided by the solid bottom bracket at the bottom of what is a chunky downtube – you can put a lot into the pedals with a lot of confidence.

Verdict

In short, so far the Topstone has lived up to its billing as a true adventure bike. It’s a jack of all trades – able to comfortably eat up tarmac and take you off the beaten track – but still a master of one: pure speed on smooth gravel.

The coronavirus pandemic has thrown my plans for this bike into limbo, and it remains to be seen when I’ll be able to explore its true potential on day-long rides and even multi-day trips. My first impressions, though, have only whetted my appetite for that.

Specifications: Cannondale Topstone Ultegra RX 2

• RRP: £2,699
• Frame: BallisTec Carbon, 55mm OutFront
• Size: Large
• Weight: 9kg 
• Groupset: Shimano Ultegra
• Crankset: Cannondale 1 cranks, FSA 46-30T, 11-34T Shimano 105 cassette, Ultegra RX GS Shadow Plus rear derailleur 
• Pedals: Shimano
• Wheels: WTB KOM Light i23 TCS
• Tyres: WTB Riddler TCS Light 37C
• Brakes: Shimano Ultegra hydro disc
• Rotors: 160/160mm RT54 rotors
• Bar: Cannondale 3 alloy, 16-degree flare drop
• Stem: Cannondale 2 alloy
• Seatpost: Cannondale 2 carbon, 27.2 x 350mm
• Saddle: Fabric Scoop Radius Elite