Cannondale Synapse Lab71 review: the smartest new bike of 2025, but I could only afford a far cheaper option

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Cannondale’s new Synapse Lab71 sets a new standard for endurance bikes, injecting high performance into the genre.

The Synapse Lab71's top-grade specification is matched to a lightweight carbon frameset and the drivetrain choice is bold.  

A single-chainring groupset on a bike designed for the road makes the Synapse Lab71 stand out among the best endurance bikes.

But with a sublimely balanced ride, integrated tech that enhances the ride experience and makes you safer, and excellent gearing, the new Synapse is 2025’s smartest bike.

However, it will be the most divisive design, too, and the price of £13,000 / $16,000 will put out of the reach of most.

Cannondale Synapse Lab71 frameset

The new Synapse Lab71 frameset takes its cues from both the lightweight road-racing SuperSix Evo and the race-oriented gravel machine, the SuperX.

The design details bring the Synapse in line with the current Cannondale road offerings. It uses the Delta steerer from the SuperSix Evo, with a standard 1-1/8x1.5in headset that still enables the brake hoses to route internally.

It also has a threaded BSA bottom bracket and uses the same seatpost as the SuperSix Evo, while the rear dropouts use SRAM’s Universal Derailleur Hanger (UDH) standard.

That means replacement gear hangers should be easy to come by (because they’re universal, not frame-specific), and it enables compatibility with SRAM’s direct-mount rear derailleurs.

Currently only found on Red XPLR AXS and the American brand’s mountain bike rear derailleurs, I reckon it will make its way soon to tarmac-focused drivetrains too. If so, the Synapse has an element of future-proofing built in.

With its blend of dropped slender stays and the smooth, slick integration of the fork crown into the hybrid truncated aerofoil and hourglass head tube, it’s a fast-looking endurance bike.

The seat tube, which blends the aero shape of the Evo into its top third with a tapering, curved leaf-spring-like design inspired by the SuperX, gives it an all-roader/gravel bike slant. When paired with the 49mm-deep Reserve carbon rims and big-volume tyres, it looks right, but on some of the lower-priced options in the range, it can look a little 'happy'.

Cannondale claims the new frame design offers 20 per cent more compliance than the previous model, while both head tube and bottom bracket stiffness are increased by unspecified amounts.

The Synapse frameset comes in two constructions: Carbon (1,150g, 56cm) and Hi-Mod (sub 1000g, 56cm), which refines the layup and carbon recipe to drop weight further. The Lab 71 frameset uses hi-mod for both frame and fork, the fork being 49g lighter than the carbon model. It also gets a special paint finish and hardware to reduce weight further.

SmartSense integration

The Synapse frame comes with plenty of features that are welcome on an endurance bike, such as mudguard/fender and bento box mounts, plus provision for a front derailleur mount and routing for Shimano Di2 wires.

The biggest change from the previous Synapse is how Cannondale has integrated the SmartSense system.

The down-tube indent and strap to hold the battery are replaced by a large storage chamber on the down tube, accessed by a quick-release cover under the bottle cage. The space is voluminous enough to house both the SmartSense battery and a good-sized storage bag (included).

Cannondale Synapse Lab71 geometry

The Synapse's geometry is largely unchanged from the previous generation – and that’s a good thing. The subtle blend of a more upright riding position and quick but stable handling has served every generation of the Synapse well since the Bike-of-the-Year-winning 2014 model.

The changes are more adaptations that help the Synapse achieve its class-leading 42mm tyre clearances. However, the new fork looks to have clearance for much wider tyres.

The head tube angle has been relaxed by 1.5 degrees to 71.5, although this has been mitigated by the use of a longer fork and a tweak to the offset (55mm). That makes for a 61mm trail figure with the standard 32mm tyres.

In comparison to the SuperSix Evo’s 58mm trail, the Synapse offers a little more stability and slightly slower handling.

The larger tyre clearance has also increased the wheelbase, thanks to longer chainstays, up to 43cm from 41.5cm.

Cannondale Synapse Lab71 specification

The elephant in the room with the Synapse Lab71 is its £13,000 price, although it does offer a no-compromises spec sheet.

The wheelset consists of Reserve’s 42mm front and 49mm rear carbon rims matched with premium DT Swiss 180 hubs and Sapim CX-Ray aero spokes. All in, it has a claimed weight of 1,341g.

The differential rims come with a 25.4mm internal width up front and 24.8mm at the rear. Reserve says the rim shape is optimised for tyres between 29 and 40mm. The wheels are set up tubeless and come with Reserve’s clever Fillmore valves, with their fast-flow, no-clog, valve-core-free design as standard. This wheelset alone would set you back £2,399 off the peg.

The wheels are wrapped in 32mm Vittoria Corsa Pro Control TLR tyres. It all adds up to rolling stock that's well suited to the bike.

Up front, the cockpit is the one-piece Cannondale System Bar R-One, designed in collaboration with automotive design house Momodesign. It’s a great-looking bar with an aero-optimised top and a comfortable mid-sized shape (80mm reach, 130mm drop).

It comes with a claimed 375g weight (400x110mm) and in plenty of options, from 380mm with 90/100/110mm stem, 400mm with 90/100/110/120mm and 420mm with 100/110/120mm. My 58cm test bike comes with the 420x110mm option.

Premium Cannondale dealers will allow you to choose your preferred option. Alone, the bar retails for £450.

The bottom bracket is a Lab71-specific threaded BSA unit made by CeramicSpeed. It's good to see Cannondale hasn’t cut any corners on parts you don’t see. The same goes for the featherweight thru-axles at only 23g and 29g – that’s less than half the weight of standard axles, with my 2020 SuperSix EVO's two axles weighing in at 129g.

The drivetrain will divide opinion because it comes from SRAM’s gravel-focused XPLR range.

The gearing here mixes a 44-tooth chainring with a wide 10-46t cassette, offering 460 per cent range. Despite this, the nine smallest ratios are only one- or two-tooth jumps, like most modern 2x systems, although the jumps get progressively larger as the sprockets get bigger.

Compared to the classic endurance ratios of 50/34T with an 11-34t cassette, with its 1:4.55 highest gear and 1:1 lightest, Red XPLR AXS offers 1:4.4 highest and 1:0.96 lightest gears. It trades a small amount at the top end, but gives a more climb-friendly option at the other end.

You also get an integrated SRAM power meter spider, which is useful for tracking and pacing your efforts.

The other opinion-dividing specification with the Synapse is the SmartSense kit.

The new front light, which is made in conjunction with Korean company Lightskin, is much slimmer and more slickly integrated into the underside of the cockpit this time round. It’s also much more powerful at 800 lumens (400 for STVZO-compliant countries). 

The rear light and radar is Garmin's Varia eRTL 615, an ebike-specific version of the standalone RTL615 radar. It differs from the standard RTL615 because it's designed in a horizontal orientation and is wired to the central battery rather than USB-C rechargeable.

The central battery is hidden in the Synapse’s down-tube storage chamber and has a 43.5Wh capacity. The battery even includes a built-in flashlight – when you open the storage hatch, you’re met with illumination, like opening a fridge door.

The battery also powers the AXS shifting and can be recharged in place through the USB-C port above the storage hatch or removed and charged off the bike.

Any battery woes affecting shifting have been considered, with protection for shifting built in, and Cannondale tells us the battery at 5% charge is still higher-capacity than a standard SRAM AXS battery.

Completing the build is Cannondale’s slender 20mm-offset (0mm-offset on smaller sizes) carbon aero seatpost, topped with Fizik’s range-topping Vento Argo 00 saddle. It’s a good match for the quality Fizik Tempo Bondcush handlebar tape.

All in, my size-58cm test bike weighs 8.3kg with all of its SmartSense accessories and bottle cages.

Cannondale Synapse Lab71 ride impressions

I’m one of the few who liked the previous-generation Synapse and the first-generation SmartSense kit, despite its flaws.

The new Synapse, however, gets everything right. The ride quality is sublime – it’s all at once remarkably smooth, hugely responsive, fast, forgiving, and above all, fun.

Over multiple rides (I’ve notched up more than 450 miles / 725km of testing so far), this Synapse has been epic. On rolling terrain, it's rapid, easily feeling as quick as my SuperSix Evo in a straight line.

The SmartSense system links to Cannodale’s smartphone app, along with the wheel-speed sensor, and can be set to wake as soon as you're moving – set the intensity of the light, and pair the radar to any compatible bike computer. I’ve tried it with both Garmin and Hammerhead units, and it's worked flawlessly with both.

Providing a real-time graphic of vehicles approaching from the rear with colour coding to represent the speed of their approach, it makes riding on the road safer and adds confidence. I’m not sure I’d want to be without one for road riding on busier routes.

The excellent wheels and tyres contribute to the responsive ride, with the large-volume tyres adding to the smooth chatter-free ride. The bike handles rougher road surfaces with ease, and even a few small excursions onto unmetalled roads were taken in its stride.

Overall, I’m enamoured by just how well the Synapse handles – its stability at speed, and on imperfect road surfaces, is up there with the best endurance bikes, such as the Specialized Roubaix, Trek Domane and Giant Defy.

A new approach to gearing

The SRAM Red XPLR AXS gearing is brilliant, with the direct-mount rear derailleur faster and more accurate than anything I’ve tried before. It won me over completely for gravel riding, but I had a few reservations about using it on a road bike. Happily, though, my fears were unfounded.

For me, whose climbing style was once described as akin to a diesel truck chugging upwards at a relentless single pace, there was more than enough scope for finding a gear to plug into at the base of a climb and spin a steady, constant cadence to the crest.

I never felt undergeared on the flat, either, although if you’re worried about a lack of top-end speed, a larger chainring (up to 46t) can always be swapped in.

Cannondale Synapse Lab71 bottom line

The new Synapse Lab71 achieves something quite brilliant. It’s a fast and fun bike, yet also supremely comfortable both in its ride position and road-chatter smoothing character. It's also versatile and practical if you embrace the SmartSense kit and the simplicity of the 1x drivetrain.

The downside, though, is that at £13,000 / $16,000, many won’t be able to afford it, although plenty of its rivals are similarly priced.

Ignoring the price, the Cannondale Synapse Lab71 is one of the best endurance bikes I’ve ridden in almost 30 years of testing bikes.

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