Cannondale has launched the Topstone Carbon gravel and adventure bike featuring a novel new Kingpin suspension system providing 30mm of compliance for a "smoother and more capable" ride, wide tyre clearance and mounting points for extra bottles, racks and mudguards.
At a glance:
Cannondale’s Topstone gravel and adventure bike has been given a carbon fibre makeover and incorporates a radical Kingpin rear suspension design providing 30mm of bump-absorbing compliance, along with lots of bottle and rack mounts, wide tyre clearance and SpeedRelease thru-axles.
Last year Cannondale launched the Topstone, an aluminium gravel/adventure bike named after a dirt road near the company’s Connecticut offices in the US. It followed in the wake of the Slate, a 650b all-road bike with a Lefty suspension fork, but where that bike shocked many, the Topstone had a more modest brief to be as affordable as it was versatile and open up mixed terrain riding to a greater many.
The new Topstone Carbon carries a lot of similarities to that bike but there are some radical differences that set it apart, not only from that bike but also most other bikes in this sector. With the new Topstone Carbon, Cannondale has set out to create the smoothest all-road and gravel bike, a bike that is comfortable on the road and highly capable off the road.
“Topstone Carbon distills our experience making fast race bikes, comfortable endurance bikes and ultra-light dual suspension mountain bikes into an exceptional machine, designed for maximum fun in places beyond most gravel bikes' abilities, or maximum comfort in more ordinary terrain,” says Cannondale.
The most radical aspect of the new bike is the Kingpin suspension. Its Cannondale’s name for flex zones in the chainstays, seat tube and top tube which, in conjunction with a thru-axle pivot connecting the seat stays to the seat tube, provides up to 30mm of compliance.
It works much like a leaf spring suspension system. Key to the design is a thru-axle pivot halfway up the seat tube spinning on two small sealed cartridge bearings. This pivot increases the rotation in the rear triangle when the rear wheel hits a bump and allows the seat tube to bow forward more than it would with fixed stays. It’s this bowing of the seat tube, enabled by the carefully shaped top tube and chainstays, that provides the compliance by allowing the seatpost and saddle to rotate backwards.
Cannondale claims this additional compliance, boosted by the SAVE carbon seatpost, provides not only increased comfort in the saddle but extra traction on rough and loose surfaces. It reckons it’s the equivalent of riding a 9mm wider tyre.
There’s no adjustment nor a rider weight limit. The bearings do add complexity to the design but not to the same degree adding linkages and shock would do. They are regular bearings and replaceable, and Cannondale has strenuously tested them and reckons they’ll easily last a year before needing a service. It’s worth adding at this point that full suspension mountain bikes use similar bearings and they don’t need replacing all that often, but it's definitely something I'll be keen to test once I get a bike in for an in-depth review.
Pivots and bearings do add weight, to the tune of about 100-150g, producing a frame weight of about 1,100g, thus ensuring it’s still a competitive weight with rival carbon gravel bikes.
The Topstone frame incorporates the Kingpin suspension with no sacrifice to the frame stiffness or pedalling efficiency according to Cannondale. The thru-axle pivot locks the left and right seatstays together to prevent any unwanted movement so it shouldn’t flex under load. Cannondale has also beefed up frame stiffness via a massive downtube connecting the tapered head tube and press-fit bottom bracket using a BB30 standard. You didn’t expect Cannondale to use anything else, did you?
Cannondale has chosen not to match the rear Kingpin suspension with any front suspension, defying some expectations for a rebirth of the iconic Headshox from the 90s or an updated Lefty as we saw on the Slate several years ago, or utilising the newest mountain bike Lefty Ocho. Offsetting my concerns about an unbalanced ride feel with the rigid front-end, Cannondale’s Design Engineer Darius Shekari assures me they have maximised the splay in the front fork to ensure the front-end provides a good amount of compliance.
Proportional Response is Cannondale’s name for a size-specific frame design that aims to ensure each rider has the same experience regardless of frame size.
The shape of the tubes and the carbon layup varies from size to size to provide the necessary stiffness and deliver a consistent experience for every size rider. The biggest sign of this is in the seat tube. It’s drastically different across the size range, from the biggest to the smallest frame size.
Cannondale has clearly defined stack and reach progressions across its road bike range, from the aggressive fit of the SystemSix aero race bike to the more laid back geo of the Topstone and Synapse, which share very similar numbers. The SuperSix Evo sits in the middle of these two extremes.
Topstone Carbon uses the company’s Endurance Fit. It’s intended to be upright enough for comfortable riding over long distances yet still low enough for gravel racers who want to tuck into an aero position. It's the same as the alloy Topstone, and the stack and reach progression is similar to the Synapse. There are five sizes from XS to XL, here’s the geometry chart:
There are some diverging schools of thought when it comes to gravel bike geometry at the moment. On the one hand, you have some brands taking inspiration from mountain bikes with very long top tubes and diddy stems, while most are sticking closer to cyclocross or endurance bikes. What's right depends on the sort of rider you are and the riding you are doing, there's no right or wrong.
This new Topstone is only available in carbon fibre, using a frame constructed from the company’s BallisTec Carbon, with the same frame shared across the range. Along with the size-specific tubing, there’s full internal cable routing, compatibility with a 27.2mm dropper post, a BB30-83 Ai bottom bracket, and an internal seat clamp just like the Synapse.
It’s disc brakes only, naturally, with Speed Release 12mm thru-axles. Speed Release is a clever thru-axle developed by Mavic a few years ago. It offers the benefits of a regular thru-axle but much easier and speedier wheel changes because the axle stays in the wheel when removed from the bike.
It’s been a couple of years since the French company first introduced it but maybe now we’ll start seeing a few more bike companies utilise it.
There are lots of mounts all over the frame and fork too. You can fit mudguards using a removable seatstay bridge, add a third water bottle, fit a top tube bag and even a front rack to the carbon fork. It’s got all bikepacking and touring needs covered.
Remember the HollowGram SAVE two-piece handlebar that was first seen on the last release of the Synapse but quietly disappeared? Well, it’s back and a key part of the top-end Topstone Carbon Force eTap AXS bike.
It’s a carbon fibre aero handlebar with a small flare and an integrated stem that provides easy handlebar angle adjustment, as well as stack and reach changes with different length stems and width bars to choose from. The flattened top section is designed to provide increased compliance over a regular handlebar.
Lower spec bikes will utilise a new 6061 butted aluminium handlebar with a 16-degree flare drop and aluminium stem.
The Topstone Carbon is the latest bike in the company’s range to integrate the new wheel sensor it developed with Garmin and Cannondale App first debuted on the Treadwell urban bike a few months ago.
The small wheel-mounted sensor automatically records rides with speed, distance and time, with a 900-hour memory enough for more than 30 days of riding, and a battery that lasts a year. The sensor connects to the Cannondale app where a plethora of services await, from sharing your ride to getting personal health reminders and also providing warranty registration, bike servicing reminders, fit and setting details and much more. It can also connect to other sensors and be paired with Garmin and other computers.
What it does not do is record location and it can be used with it without a smartphone. Cannondale believes it’s about adding value to the ownership experience, to expand its focus from not just the bike but to the entire experience of owning a bike to make riders better and make bikes better.
There will be five models in the Topstone Carbon range priced from £2,099 to £4,799. The top model gets SRAM’s latest Force eTap AXS groupset in a 2x configuration with a 10-33t cassette and 46/33t chainset.
Wheels are Cannondale’s brand new Hollowgram 22 carbon fibre hoops with a 22mm deep rim and 25mm internal width, with tubeless WTB Riddler 37mm tyres fitted. There’s the aforementioned HollowGram SAVE handlebar and Fabric Scoop Shallow Race saddle with titanium rails rounding out the build.
Next up us the Topstone Carbon Ultegra RX (£3,499) which uses a Shimano Ultegra RX mechanical rear mech with matching shifters and hydraulic brakes, and Cannondale’s new HollowGram SI crankset with 46/30t chainrings paired to an 11-34t cassette. It also uses the new Hollowgram 22 carbon fibre wheels with WTB Riddler 37mm tyres.
There’s a women’s Topstone Carbon Ultegra RX (£2,699) bike which comes in three sizes - XS, S, M - and uses different contact points to tailor the fit. It also swaps the Hollowgram 22 wheels for WTB KOM Light rims on Formula hubs but keeps the same Riddler tyres.
The Topstone Carbon Ultegra RX 2 (£2,699) uses a Shimano Ultegra RX mechanical groupset with WTB KOM Light rims and a Cannondale crankset with FSA 46/30t chainrings.
Propping up the range is the Topstone Carbon 105 (£2,099) with Shimano 105 mechanical gears and hydraulic brakes, WTB ST i23 rims and WTB Riddler 37mm tyres and a Fabric Scoop Shallow Sport saddle, and a choice of two paint jobs.
I headed to Vermont for the worldwide launch the new bike where I got to ride the Topstone Carbon on a variety of pavement (what they call roads over here), graded dirt roads and some singletrack. It's clear Cannondale has built a bike that provides a very fast ride with good comfort and smoothness, and it was good at dealing with rough surfaces extremely well.
For more of my first ride impressions on the new bike, you can read my detailed first ride article here.
More info at www.cannondale.com
David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.