It’s a well-known fact that the bragging rights for any given ride are taken on the hills, and specifically when you’re going up them. Strava trophies are awarded to the King/Queen of the Mountain after all, and the most prestigious segments are climbs.
So, if you want to be the best climber, you’re going to need the best climbing bike, right? It all makes perfect sense.
With that firmly and irrefutably established, what are the most important things you should be looking for in a bike designed for climbing?
Best climbing bikes: what to look for
It perhaps goes without saying, but when you’re riding uphill, gravity is always trying to pull you back down.
Reducing the total rider plus bike system weight means less energy (or power, in cycling parlance) is required to maintain a given speed while climbing.
Therefore, if you want to ride uphill faster, or simply make the hills a little easier for you, a lightweight bike is an obvious move.
It’s for this reason we see hill-climb obsessives chopping and changing practically every component to bring their overall bike weight down to its lowest possible limit.
Until fairly recently, climbing bikes made no concessions to aerodynamics. But with the rise of computer modelling, on-bike aero sensors and other advanced testing techniques, this has all changed.
Even dedicated climbing bikes are now launching, touting their aerodynamic efficiency.
Take Trek’s recently launched 2021 Emonda, for example. Trek says it has been designed specifically for the rigours of iconic Tour de France climbs such as Alpe d’Huez (a 13.85km monster in the French Alps), yet still features extensive aero treatment.
We won’t deny that there’s usually a minor weight penalty associated with such aero features, but clearly brands have deduced that, on balance, it’s worth it.
We’ll discuss this particular issue in more detail in our buyer’s guide at the end of the article, so keep reading once you’ve read all the reviews.
Now, onto the best climbing bikes in 2021.
The best climbing bikes in 2021, as rated by our team of expert testers
- Cannondale SuperSix EVO Hi-Mod Disc Dura-Ace Di2: £9,000 / $11,500 / €10,499 / AU$12,999
- Focus Izalco Max 9.7 AXS: £5,699 / €6,199 / AU$8,999
- Giant TCR Advanced SL 0 Disc: £9,699 / $11,000 / AU$13,499
- Orbea Orca OMX M10i LTD D: £7,899 / $9,299 / €8,999 / AU$12,999
- BMC Teammachine SLR 01 Two: £9,800 / $10,999 / €10,499
- Canyon Ultimate CF SL Disc 8.0 Di2 Aero: £3,749 / €3,999 / AU$5,299
- Giant TCR Advanced Pro 2 Disc: £2,999 / €3,100 / $5,199
- Specialized S-Works Tarmac SL7: £10,500 / $12,000 / €11,499 / AU$18,000
- 2021 Trek Emonda SL 6 Pro: £3,350 / $3,799 / €3,799 / AU$5,499
- Vitus Vitesse EVO CRS Di2: £3,699.99 / $4,499.99 / €4,199.99 / AU$6,399.99
- Specialized S-Works Aethos: £10,500 / $12,500 / AU$18,500
Cannondale SuperSix EVO Hi-Mod Disc Dura-Ace Di2
- Fast, comfortable road bike with excellent spec and wonderful handling
- Comes at a high price, and the extra payment needed to activate the power meter is irritating
- Price: £9,000 / $11,500 / €10,499 / AU$12,999
The successor to one of the most renowned carbon climbing bikes, Cannondale’s latest evolution of the SuperSix EVO Hi-Mod broke with tradition and added features such as aerodynamic tube shapes and components, and disc brakes.
Yes, these features have added a little weight, but being built around a frame and fork that weigh 866g (56cm) and 389g respectively, this top-end build is still competitive in the weight department.
Our size 58cm test bike weighed 7.51kg, and that’s with aero wheels, 25mm tyres, an aero cockpit and a spider-based power meter.
The obvious downside is the price, but those less willing to part with such lofty figures might also consider the Cannondale SuperSix EVO Carbon Disc Ultegra, which comes in at a third of the price but only weighs around 800g more.
There are also three women’s-specific builds available, built around the cheaper, non Hi-Mod frameset.
- Weight: 7.51kg (58cm)
- Gearing: 52/36, 11-30
Focus Izalco Max 9.7 AXS
- Racy handling and fast feeling road bike
- Decent value compared to the competition
- Price: £5,699 / €6,199 / AU$8,999
Similar to many other bikes in this category, Focus has evolved its Izalco platform to be more well-rounded.
The latest version takes both weight and aerodynamics into account, but doesn’t go so far as to ignore practicality completely – the aero cockpit, for example, uses a standard stem and handlebar set-up to make fit adjustment and maintenance a little easier.
At 7.9kg (size large), it’s not the lightest bike we’ve ever tested but this does include 50mm deep aero wheels and, with a frame weight of just 890g (claimed), it could certainly be lightened up considerably with a few weight-weenie optimisations.
There’s also a slightly cheaper version, the Izalco Max Disc 8.8, that has Ultegra R8000 mechanical gears, but performed similarly well in our testing.
- Weight: 7.9kg (large)
- Gearing: 48/36, 10-28
Giant TCR Advanced SL 0 Disc
- Light, stiff and responsive race bike
- Price: £9,699 / $11,000 / AU$13,499
The TCR has long been a benchmark for race bikes and the new-for-2021 ninth generation of the bike remains a top performer.
While the TCR comes in many variants to suit different budgets, the Advanced SL 0 model is unapologetically high-end and its frameset sports an integrated seatpost with a topper rather than a conventional one.
With a full SRAM Red eTap AXS wireless groupset and carbon wheels from Giant’s in-house brand Cadex, it’s ready to race out of the box and is properly light.
- Weight: 6.7kg (L)
- Gearing: 48/35, 10-28
Orbea Orca OMX M10i LTD D
- Excellent all-round ride and generous tyre clearance
- Clean build with smart component integration
- Price: £7,899 / $9,299 / €8,999 / AU$12,999
The new Orca OMX has a wonderful blend of low weight, firm pedalling stiffness, decent aero credentials and confident handling that make it an absolute joy to ride.
We also really appreciate the care with which Orbea has integrated the cables. It makes for a beautifully clean front end, without any compromises in fit, and it’s not overly complicated to put together either.
Our test bike weighed 7.5kg (size large), complete with aero wheels. This doesn’t trouble the UCI weight limit, but with an 833g frame and 370g fork (claimed weights), it could certainly be built lighter, if you felt the need.
Orbea also offers the slightly cheaper Orca M25 Team-D.
- Weight: 7.5kg (large)
- Gearing: 50/34, 11-30
BMC Teammachine SLR 01 Two
- Lightweight and faster than ever before
- Very little to fault, but it comes at a high price
- Price: £9,800 / $10,999 / €10,499
Only very recently announced, the latest iteration of BMC’s excellent Teammachine learns lessons from the Timemachine (BMC’s aero road bike) to improve its aerodynamic efficiency, without adding too much weight.
In fact, its 7.09kg weight makes the BMC Teammachine SLR 01 Two one of the lightest bikes on this list, and that’s seriously impressive considering it has aero wheels, disc brakes and plenty of other aero features.
The omission of a Dura-Ace crankset is perhaps the only minor criticism we could make of a bike that’s otherwise extremely hard to find fault with. There’s no denying it comes at a very high price though.
- Weight: 7.09kg (56cm, including two bottle cages)
- Gearing: 52/36, 11-30
Canyon Ultimate CF SL Disc 8.0 Di2 Aero
- Lightweight and aero optimised, but the sharp handling may not be for everyone
- Excellent value build
- Price: £3,749 / €3,999 / AU$5,299
As always, Canyon provides an excellent value, race-ready package, right out of the box.
Despite the lack of dropped seatstays, the back-end is still comfortable. So much so, in fact, that the sharp front-end handling initially feels a little out of step with the rear, but this is a race bike after all.
At a shade over 7.5kg, it’s lightweight for a bike of its size, which has disc brakes and aero wheels, and three are women’s-specific builds available too.
- Weight: 7.54kg (large)
- Gearing: 52/36, 11-30
Giant TCR Advanced Pro 2 Disc
- Solid all-round spec with lively ride quality
- Lots of tyre clearance
- Price: £2,999 / €3,100 / $5,199
The legendary TCR has finally gone aero for 2021, but that doesn’t mean a huge increase in weight, fortunately.
At 7.87kg, it’s not the lightest bike on this list, but it’s very competitive in its price range and could likely be lightened considerably with some component upgrades.
It also offers a noticeably smooth ride, with confident handling and clearance for up to 32mm tyres, which is very welcome.
Giant’s sister company Liv offers a women’s-specific version called the Langma Advanced Pro Disc.
- Weight: 7.87kg (medium/large)
- Gearing: 52/36, 11-30
Specialized S-Works Tarmac SL7
- Flagship race bike as ridden by Peter Sagan
- Stiff, fast and beautifully finished
- Price: £10,500 / $12,000 / €11,499 / AU$18,000
Few bikes generate as much hype as the new Tarmac did when it launched in 2020.
This new flagship merged Specialized’s aero and lightweight platforms into one, claiming real aero gains over its predecessor and sporting a frameset weighing a claimed 800g for a 56cm.
The Tarmac SL7 is disc-only and has clearance for 32mm tyres. It’s a fast and uncompromising race bike that will delight riders who can kick out big power numbers.
In its halo S-Works spec this is a seriously expensive bike, but more affordable models are available, with the second-tier frame claimed to weigh a respectable 920g.
- Weight: 6.7kg (54cm)
- Gearing: 48/35, 10-33
- Read our full review of the Specialized S-Works Tarmac SL7
Trek Emonda SL 6 Pro
- Stiff and exciting ride quality
- Great quality components
- Price: £3,350 / $3,799 / €3,799 / AU$5,499
Inline with market trends, Trek has amended the Emonda’s design parameters to encompass a broader, all-round riding style, with the obligatory disc brakes and aero optimisation.
This does mean final builds won’t quite be able to match the positively feathery lows of previous models, but Trek is, unsurprisingly, adamant they will nevertheless be faster most of the time. Our tester broadly agrees with this sentiment too, heaping praise on it for its speed and stiffness.
It’s also worth considering Trek’s beautiful Emonda ALR. Not only are there rim and disc brake versions of that frame (as things stand), but it’s also substantially cheaper. We think it’s an absolute peach of a bike.
For 2021, Trek says the Emonda is now a unisex bike, and offers a broad range of sizes (from 47cm to 65cm) with the intention of fitting all different kinds of cyclists.
- Weight: 8.13kg (56cm)
- Gearing: 52/36, 11-30
Vitus Vitesse EVO CRS Di2
- Very competitive spec
- Racy personality and low weight
- Price: £3,699.99 / $4,499.99 / €4,199.99 / AU$6,399.99
The Vitesse received a major update for 2021 and is now a disc-only racer, one that’s ridden by actual pro cyclists. The frame weighs a claimed 910g and sports very up to date styling, with all cabling routed into the non-driveside.
More affordable builds than this one are available, but even with Shimano Ultegra Di2 and low-profile Reynolds carbon clinchers as we tested it, it’s keenly priced.
The Vitesse is a firm and focused ride that will appeal to racers, but may be a little uncompromising for more casual riders.
- Weight: 7.6kg (M)
- Gearing: 52/36, 11-32
- Read our full review of the Vitus Vitesse EVO CRS Di2
What we’ve included (and what we haven’t)
This buyer’s guide features lightweight bikes at a range of prices, reviewed by BikeRadar and having scored at least four stars in our testing.
While lighter bikes may be available (including custom builds and different models within a given manufacturer’s range), these are bikes we have tried and tested, and can confidently vouch for as a result.
Specialized S-Works Aethos
Not yet rated
- Lightest production disc frame on the market
- Stunning ride with a price tag to match
- Price: £10,500 / $12,500 / AU$18,500
Where the Tarmac is Specialized’s pro race bike, the Aethos ignores aero and focuses on being the best riding bike.
Its frameset combines more traditional features (non-dropped seatstays, a threaded bottom bracket, internal but not fully internal cables) with cutting-edge carbon construction and a huge spec. Claimed weight for a 56cm frame is just 585g, a truly astonishing figure.
We haven’t given it a score yet, but it’s safe to say this remarkable machine belongs in a list of the best climbing bikes.
- Weight: 6.1kg (54cm)
- Gearing: 52/36, 11-28
- Read our first ride review of the Specialized S-Works Aethos Dura-Ace Di2
Buyer’s guide to climbing bikes
Carbon vs aluminium
We’ve explored this many times before, but with carbon fibre frames and parts still commanding a healthy premium over aluminium ones, it’s worth touching on here.
Top quality carbon fibre is prized for its incredible stiffness to weight ratio, and rightly so – this is the reason it’s used in Formula One. If you can afford it, the lightest bikes and parts will almost always be made out of high-end carbon fibre.
At the lower end though, good aluminum is competitive with, or even better than, cheap carbon fibre. That applies not just to weight and stiffness, but also for ride quality and strength.
The very last of those characteristics is also a general worry for ultra-lightweight carbon fibre frames and parts, in general. You have to be very careful about sticking to recommended weight, torque and clamping specs, or else it’s very easy to break these feathery items.
Aero vs. weight for climbing
It would be easy to think that when you’re going uphill, weight is the only thing that matters. It is, of course, important. After all, a 5kg reduction in total rider plus bike weight will shave around 39 seconds off a 2km, 10 per cent climb, all other things being equal.
But with our many years of collective experience we’ve found that body weight matters much more than bike weight. Besides, unless you can get your hands on something like Berk’s 3.9kg bike, you’re going to struggle to shave anywhere near 5kg off your bike’s overall weight, no matter how deep your pockets.
On top of that, more and more brands are discovering that aerodynamics are still important when riding uphill, and for saving energy on the way to the bottom.
Even a brand such as Cannondale, which used to make the definitive, ultra-lightweight hill climb bike, believes its full-on aero bike, the SystemSix, is the faster on gradients up to 6 per cent than its own lightweight bike (the SuperSix) – even at the typically slower speeds mere mortals like us ride at.
True hill climb aficionados will no doubt be tearing their hair out at this point, exclaiming ‘anything under 10 per cent isn’t even a proper hill anyway!’, but if you want to go fast, aero always matters, regardless of the gradient.
It’s true that aerodynamic drag becomes a smaller part of the equation as gradients increase in severity, but the absolute amount of air resistance you experience remains the same for any given speed.
On top of that, the power to overcome any increase in air resistance is proportional to the cube of speed. So, if you want to ride your bicycle twice as fast, you’ll need eight times more power to overcome the extra drag force, unless you can reduce your aerodynamic drag.
In an ideal world, then, you want a bike that’s both lightweight and aero for smashing hills.
“Weight weenies should be Crr weenies”
So said Robert Chung, Professor and Theoretical Mathematical Demographer at the University of California-Berkeley. Chung is perhaps most famous for devising the ‘Chung Method’ of calculating aerodynamic drag, but he also reminds us of the importance of not ignoring rolling resistance too.
Using a power equation for wheeled vehicles (like the one found at www.kreuzotter.de), he showed that even a relatively small difference in rolling resistance (Crr stands for ‘coefficient of rolling resistance’) can be worth as much as large changes in weight, even on steep gradients.
Weight weenies should be Crr weenies. We can convert differences in Crr to "equivalent" differences in mass. Even small differences in Crr are equivalent to 100's of grams of mass difference on steep hills. pic.twitter.com/YSASEisid0
— Dr. Anti-social social scientist (@therealrchung) April 28, 2019
On a flat road, it’s clear that even a relatively small decrease in rolling resistance is worth more than practically any increase in weight. What’s really interesting to note though, is that changing from a GP4000 to a GP5000 is still worth more than 500g of extra mass even on a 10 per cent slope.
Yes, that’s right; the small difference in rolling resistance between two excellent tyres can have a greater effect on your efficiency than 500g of extra weight even on a 10 per cent slope, and that equivalent mass penalty only increases as the gradient gets shallower. On a 6 per cent slope, the difference is equivalent to a kilogram of extra mass.
The key takeaway is that you shouldn’t just look at weight figures when shopping for tyres. The differences in rolling resistance between tyres will be worth far more to your climbing speed than any minor weight variations.
Gearing and cadence when climbing
Some riders apparently enjoy using singlespeed or even fixed gear bikes for climbing hills! But most people are going to want gears.
For a long time though, back in the days when riders only had five or so cogs on their cassette to choose from, gears such as 42×21 were considered adequate for climbing mountains.
Thankfully, though, things have moved on and we now have access to compact/sub-compact chainsets, long-cage rear derailleurs and much larger cassettes. Used together, these can allow practically anyone to spin up steep climbs, rather than turning them into a series of leg presses.
Muscling up a steep hill in a massive gear might feel heroic, but it’s probably slower and it’s costing you more energy too, as anyone with a power meter will be able to attest to. These days, even the pros know you need to gear down when the road goes up.
Rim or disc brakes
Another thorny issue. In our opinion, there are two answers to this; a simple one and a nuanced one.
The simple answer is that rim brakes are, generally, lighter, and therefore are better for climbing bikes.
The more nuanced answer is that while disc brake-equipped bikes generally do come with a weight penalty over equivalent rim brake models (though this is becoming harder to measure because, despite what we wrote in 2017, new high-end rim brake bikes are becoming increasingly less common), the advantage of better braking will be keenly felt on the way down the hills.
If the only thing you care about is going uphill as fast as possible, then rim brakes could still be the right choice. Otherwise, the advantages of disc brakes in a more general sense might tip the balance.