Cannondale Topstone Carbon Lefty 1 review

Last year's Cannondale Topstone – with its innovative Kingpin suspension frame – was one of our favourite gravel bikes and a finalist in our Bike of the Year award. This year Cannondale has gone one better, adding front suspension into the mix and taking the Gravel Bike of the Year crown for 2021.

And Cannondale being Cannondale, a company that likes to go its own way, it has of course gone for a distinctive single-bladed Lefty fork. After all, why have two blades when one will do?

The same is also true when it comes to chainrings, this Topstone coming with a SRAM Force AXS 1x chainset paired with a 12-speed cassette and a rear mech from SRAM's off-road Eagle X01 groupset.

The Topstone platform is compatible with both 650b and 700c wheel sizes – the new Lefty-equipped models have the smaller 650b size while the non-Lefty carbon Topstones are specced with 700c wheels.

With its super-low-slung back end and mono-blade fork, Cannondale's Topstone Carbon Lefty 1 is a very striking-looking bike.

The Topstone's intricate brake fittings, with their quick-release system, look like a glimpse into the future and it all holds together well, with the metallic colour-shifting finish and high-grade finishing kit you'd expect on a bike at this price.

Cannondale Topstone Carbon Lefty 1 frame

The most obvious feature of the Topstone Carbon Lefty 1 is something that's rare in the world of drop-bar bikes – suspension.

Both the frame and fork are designed to offer 30mm of travel, which may not sound a lot compared with modern mountain bike suspension, but it makes a world of difference to how this bike handles over even the poorest of surfaces.

The frame's Kingpin suspension system is designed to offer 30mm of travel at the saddle, with around 25 per cent of that (7.5mm) at the rear axle. Cannondale has engineered the Topstone's seat tube to work as a leaf-spring, with flex zones in the frame's chainstays and top tube to enable the movement.

The pivot at the top of the seatstays runs on a maintenance-free bearing, which allows the rear end to move freely without the added complexity or additional weight of a shock unit and linkages.

The leaf spring design is proportional to the size of the bike, so that whatever size of frame you're riding, they will all feel the same.

The difference in diameter on the thinnest section of the seat tube is marked – measuring 16mm on the small frame, 28mm on the XL. Tube cross-sections and the laminate of the carbon fibre are also scaled to deliver a consistent riding experience whatever the size of the bike.

The frame has a thru-axle, in this case with a 'Speed-Release' dropout – a thru-axle but with one of the dropouts slotted. This lets you release the wheel without having to take out the axle completely.

This brings us to the single-bladed Lefty fork. Cannondale undertook a major redesign of its Lefty mountain bike fork in 2018, moving away from the bulky twin-crown design to a single-crown fork with standard dimensions, allowing it to fit any bike.

The new Lefty Oliver fork is a scaled-down version of that design for lighter gravel use. The carbon version weighs 1,340g, which compares with the mountain bike version's 1,446g, while the alloy model's 1,610g undercuts the off-road fork's 1,735g – noticeable weight differences.

The reshaped single crown has clearance for 47mm 650b tyres and 45mm 700c tyres. The Lefty Oliver retains the same high levels of lateral and fore-and-aft stiffness as the mountain bike fork, which has earned a great reputation for stiffness, especially in its shorter-travel versions.

It features Cannondale's 'Delta Cage' needle-bearing system, in which the three roller bearing assemblies are held in a lightweight polymer cage. This means that the bearing sets move in unison and can't work against each other, vastly reducing friction.

Cannondale tells us it has done a lot of work to prevent any pedalling-induced 'bobbing' and claims the Lefty Oliver is both very stable and yet open on hits.

Cannondale has also isolated the fork's rebound adjustment from its compression and says the new Oliver offers 60 per cent more rebound range than the original Slate Lefty fork. But even with this claimed improvement in control, Cannondale has included a manual lock-out lever on the crown for when you're riding on the road.

This lock-out is designed to 'blow-off' though, so should you hit an obstacle, it will open up and allow the damper to absorb the bump.

The Oliver fork also comes with a quick-release system that allows you to remove the flat-mount brake assembly, which has a very secure locking mechanism when you replace it.

Though my experience of single-sided forks suggests you rarely need to remove the wheel for switching tyres or repairing punctures, removal only really becomes an issue when it comes to brake maintenance or serious wheel issues.

Cannondale Topstone Carbon Lefty 1 kit

The Topstone Carbon Lefty 1 has a 'mullet' drivetrain – small at the front, large at the back. It mixes components from SRAM's Force AXS road groupset and Eagle AXS mountain bike groupset.

The 12-speed setup with its 40t chainring and 10-50 cassette provides a massive range of gears. The 40×10 top gear is around 108in with the Topstone's wheels and tyres, equivalent to between a 50×12 and 50×13 on a compact, while the 21.5in delivered by the 40×50 bottom gear is much lower than the 28in of a 34×32 pairing.

This means you'll have an easier gear for climbing, where on a lot of bikes you'd be reduced to walking. At the other end I'd say the top gear is plenty for even the fastest off-road riders – and ample for most of us on the road 99 per cent of the time.

If you're a smooth-pedalling roadie you may find the jumps between gears larger than you're used to, but in low-traction, rough-riding situations you don't tend to shift gears quite as much as you do on the road. And, frankly, I'd much rather have a bike with a gear range that keeps me turning the pedals than closer ratios where I'll end up pushing – I want to be riding, not hiking.

The shifting is up to SRAM wireless AXS’s usual accurate standards and AXS's intuitive shifting logic – right hand harder, left hand easier – works well here.

The SRAM Force brakes and Paceline rotors offer bags of stopping power along with fine control

Connect AXS to SRAM's app and you can control the settings and record numerous metrics on every ride. Want to know what gear you use the most and how many times you change gear (you do, don't you?) as well as a wealth of GPS data, well, this will give you that.

You can also add a power meter and heart rate monitor for the full complement of facts and figures. It's quick and easy to connect to a Garmin too, so you can see your gear data on screen and keep track of the battery level.

The SRAM Force brakes and Paceline rotors offer bags of stopping power along with fine control, progressively ramping up the braking through the lever travel, and the Lefty suspension fork doesn’t dive even under full-on braking loads.

The HollowGram 23 Carbon wheels are an ideal complement to the Topstone's frame and their 23mm internal rim width is perfect for the Cannondale's large volume 47c tyres.

Their DT Swiss internals should prove durable and they're laced to the rims with DT Swiss spokes. The rims are from Cannondale's mountain bike stable, and their high-impact carbon is designed to take serious abuse.

The Topstone's front wheel has the addition of the Cannondale's Wheel Sensor, which was developed in conjunction with Garmin. This measures speed, time and distance and has on-board storage for up to 900 hours.

It works with Cannondale's own app or any head unit compatible with BLE and ANT+. I connected it to a Garmin Edge 1030 where it automatically recorded all rides. It runs off a single CR2032 cell and has a claimed battery life of a year.

You connect the app to your bike by simply spinning the wheel, which lets you register your bike for its warranty. In addition to the usual metrics, the app can also display calories burned and even how much CO2 you've saved compared with doing the journey by car. It also gives you maintenance reminders – for lubing, servicing, bleeding the brakes – and you can add bike fit details, too.

And there's more: you can also add your achievements and goals, technical manuals and there's even a fun X-ray function – an augmented reality screen that shows what’s going on underneath the skin of your bike, the internal cable routing for instance.

You can use the app as a standalone ride log as well – it instantly logs rides and can save 30 days of riding – or in conjunction with Strava.

There were a couple of areas where I would have changed things. I'd have liked a little more flare in the handlebar because this is a bike that's designed to be ridden off-road. I'm not a big fan of excessively flared gravel bars but I do like a little more wrist clearance than is offered here.

It is a high-quality cockpit though, pairing the excellent SAVE SystemBar and SAVE stem Cannondale uses on the EVO, which look great and add comfort. I'd have just liked a little more flare.

Dropper posts, which let you lower the saddle in an instant, are now staples of mountain bikes and given the Topstone's impressive off-road capabilities, being able to drop your saddle – especially on technical descents – would have been a real bonus. The Topstone Lefty 1 is at least dropper post-compatible but given its price, I'd like to have seen Cannondale include it as standard.

Cannondale Topstone Carbon Lefty 1 geometry

The geometry of the Kingpin-equipped Topstone Carbon Lefty 1 frame is based on Cannondale’s award-winning Synapse – our Bike of the Year back in 2014.

My large model has 610mm of stack, which is the same as a 58cm Synapse, with the 394mm reach figure 1mm longer than that of the Synapse.

That difference comes from the Topstone's slacker head angle – 71.2 degrees compared with the Synapse's 73 degrees – and its greater fork offset.

The Topstone's 55mm of offset, and wheel and tyre size deliver 58mm of trail, giving the Topstone a handling sweet-spot. The steering feels swift, like that of an endurance bike, with the relaxed head angle adding stability when the going gets rougher.

Cannondale calls this its 'OutFront' geometry and it has the added benefit of reducing the chances of toe overlap, and toe overlap is the very last thing you want on tight, technical terrain.

Cannondale Topstone Carbon Lefty 1 ride impressions

Now this is where Cannondale's new Topstone really scores well – on tarmac, trail and beyond the Topstone gives you just so much control.

The rebound from the fork feels natural. Even when you're riding fast, technical off-road sections with drops and jumps, the Lefty fork never topped or clunked, ramping progressively until very firm.

The 30mm of travel may not seem a lot but in the early days of mountain biking the likes of John Tomac would hit 50mph downhilling on a bike with a similar level of suspension.

The Topstone copes with bad surfaces better than anything else out there and will open up a world of new terrain to explore. Add in its mountain goat gearing, controlled compliance from the suspension and generous tyres and this is the most capable gravel bike I've tested to date.

The handling is quick but not twitchy, stable but not dull and inspires such confidence that it will allow you to throw caution to the wind.

Another factor that magnifies the Topstone Lefty 1's off-road capabilities is the use of tyres with differential treads. The front WTB Venture tyre has block edges that bite in the corners to provide plenty of grip, the WTB ByWay rear has a much slicker tread that helps transfer pedalling into forward motion.

This has long been an approach in mountain biking and cyclocross and it's strange that it's taken so long for road and gravel bikes to catch on. So credit to Cannondale for making the move.

I gave high praise to the standard 700c non-Lefty Topstone for its wonderful on-road manners – even mooting it as a replacement for Cannondale’s Synapse endurance bike for many riders.

This sprung Topstone Carbon Lefty 1, with its smaller wheels and fatter tyres, isn't quite the Synapse-killer of its unsprung sibling but it is capable enough on the tarmac.

The ride position is classic endurance and the WTB tyres' slick centre strips don't create as much drag as many chunky gravel tyres. I'd still emphasise that this is a bike built for the path less travelled rather than the road – but on tarmac sections between the dirt, it's still a sufficiently swift performer.

As for its 10kg weight? Forget about it. This Topstone Lefty doesn't deserve any body shaming because within a few turns of the pedal off-road you'll be believing this was a UCI limit-baiting lightweight, such is the way it flies over rough surfaces.

Try thinking of the Topstone less as a hefty drop-barred bike and more like a super-light drop-barred mountain bike that won't sap your energy on the road.

Cannondale Topstone Carbon Lefty 1 bottom line

Cannondale's Topstone Lefty 1 is a phenomenal companion for getting you way, way off-road, and it will let you ride faster over traditional gravel routes than its rivals.

Okay, so we are looking at Cannondale's most expensive Lefty-equipped Topstone but the range starts at £4,000 for the Topstone Carbon Lefty 3, which comes with an alloy version of the Lefty fork and 1x Shimano GRX gearing.

I'd go as far as saying if you are looking to get away from the old routine of riding day-after-day on tarmac, Cannondale's innovative Topstone Lefty 1 is the ultimate way to expand your horizons much further than you ever thought possible.

You really don't notice the little extra weight the Topstone's carrying, what you do appreciate is the control from the Lefty suspension fork and front- and rear-specific WTB tyres, its comfort and the Topstone's class-leading handling over rough terrain and technical off-road sections.