The top racers in the world used to all ride hardtails for minimum weight but tougher courses mean most of the best XC mountain bikes are now full-suspension models.
For information on Bike Perfect's testing procedures and how our scoring system works, see our how we test page.
The great news is that the shift has led to some really versatile high-velocity, short-travel machines that are as happy raving on your favorite singletrack as they are ripping up a race course. But which are the winning machines and what do you need to know before you buy? Here's everything you need to know to find the best XC mountain bike for you.
Meet the tester
Why trust BikePerfect Our cycling experts have decades of testing experience. We'll always share our unbiased opinions on bikes and gear. Find out more about how we test.
Guy Kesteven is Bike Perfect’s contributing tech editor. Hatched in Yorkshire, he's been hardened by riding round it in all weathers since he was a kid. He spent a few years working in bike shops before starting writing and testing for bike mags in 1996. Since then he’s written several million words about several thousand test bikes and a ridiculous amount of riding gear.
The best XC mountain bikes with full suspension
Santa Cruz haven’t had a proper podium-focussed full-suspension XC race bike in their line up for years but the fourth-generation Santa Cruz Blur impressed us so much that we awarded it five stars in our full review.
While Santa Cruz's trail bikes from Tallboy to Megatower all look the same and share the same suspension system, the Blur is totally different. The 'Superlight' suspension system uses flex in the seat stay and a top tube mounted shock to give 100mm of travel. That’s matched by the ultralight RockShox SID SL fork up front but there’s also a 120mm TR version of the bike available.
SRAM’s X01 Eagle AXS wireless drivetrain along with SRAM Level RSC brakes delivers top spec stop and go. Lightweight Reserve carbon rims are responsive yet controlled while the 100mm Fox Transfer SL dropper post is just enough for jiving on tech trails. Despite being seriously light you still get a full lifetime warranty on frame, rims, bearings and handlebars, and no weight restriction either.
It's the effortless acceleration and effervescent flow and fun of the Blur that really made it a favourite of our testers, though, both on the race track and off.
Check out our in-depth five-star review of the Santa Cruz Blur.
The Scott Spark is by far the most successful cross-country race bike of the last decade, and the latest model is faster and more controlled, as well as looking uniquely sleek.
The most obvious change is that Scott have hidden the rear shock inside the frame so that it’s not exposed to the elements. The brand has also bumped up the rear suspension travel to 120mm on all Spark models, not just the downcountry/trail ones. The already progressive, control-boosting geometry can also be made a degree slacker in just a couple of minutes on the trailside.
The Team Issue AXS is a real sweet spot in terms of value for racers too. The excellent RockShox SID fork and Deluxe rear shock suspension feature bar lever controlled open, traction and lock settings for maximum efficiency. The SRAM GX Eagle AXS electronic drivetrain is flawlessly fast and you get the superlight Syncros Hixon all in one carbon cockpit. The Syncros Silverton wheels are light too and Maxxis Rekon 2.4in tires roll super fast while staying rocky section safe.
All it's really lacking is a dropper post, although some racers still don't use them so the omission is forgivable. Also, if you’ve got the cash for an ultimate race bike, even lighter HMX and HMX SL versions of the frame with carbon Syncros wheel options are available.
Read more about the bike in our full Scott Spark Team Issue AXS review.
The best downcountry bikes
With trail bikes getting heavier and travel getting longer all the time, a new breed of agile, responsive but still impressively controlled and fun-to-rally 'downcountry' bikes have appeared. A lot of the models that claim to be in this category are too heavy or slow, however, so we've picked our favourites carefully.
The Izzo is YT's debut into the lightweight full-suspension bike category is more downcountry than cross country with 130mm of travel front and rear. However while this may not be a pure-bred race bike, it can keep up with the pack on climbs and then shred them on the descents.
The suspension is Kashima-coated, Fox Factory series with a 34 fork up front and Float shock at the rear, and the shock has a remote lockout. The bike is outfitted with a SRAM X01 Eagle 12-speed drivetrain and SRAM G2 brakes. The DT Swiss XMC 1200 Spline wheels are wrapped in Maxxis tires.
While the Pro Race launch spec version we tested was already light for its category, YT have now bought out an 'Uncaged 7' version of the Izzo with RockShox SID suspension and Maxxis Rekon Race tires at both ends. This drops travel to 120mm but at just 11.4kg and with faster rolling rubber it’s a proper rocket ship.
Check out our full review of the YT Izzo Pro Race.
The Epic has been Specialized's flagship XC bike for a number of years now, and this year the brand introduced an EVO version for those who want a bit more travel and handling prowess.
The suspension is bumped up to 120mm front and rear, which is handled by a RockShox SID combination. You also get a 150mm dropper post from X-Fusion to keep the seat out of the way. A SRAM groupset and brakes complement Roval rims wrapped in Specialized's own tires.
The Epic Evo is on the lightweight side of the downcountry bike segment, and can still keep up on technical race circuits. If you're looking for a bargain, the Comp version of this bike has all the trail-shredding capability but is even greater value for money.
It's light enough to race but rowdy enough to rally – out our in-depth opinion in our Specialized Epic Evo Expert review.
The best XC bikes for rapid trail riding
The RC9000 version of Merida's XC race bike lineup features sorted suspension, a stiff frame and improved handling. The presence of Kashima-coated Fox Factory suspension front and back, and a full Shimano XTR groupset also helps make it a proper flagship machine. Like most Merida bikes it offers great value for money compared to top XC bikes from other brands.
Even though this bike is a bit heavier than its competitors, it's still effortlessly efficient with a blisteringly quick baseline. Slacker and longer geometry than previously hysterical Merida race bikes means acceptable stability for attacking fast technical XC circuits. It's also less stressful for extended distance rides or marathon events. There's a longer fork version if you want to gain rally capability at the expense of race weight, though if you get this flagship version, watch out for the awkward remote lock out and bleed-needy brakes.
If you want more detail check out our full review in which we went epic in full winter conditions to test the Merida Ninety-six RC9000.
Cannondale's Scalpel full-suspension mountain bike can slice and dice with the best XCO bikes out there. The SE model range keeps the speed but relaxes the bike's geometry to move it more towards the downcountry space.
A 120mm suspension platform is filled out by a RockShox fork and rear shock that lead to efficient pedaling and excellent sensitivity on technical trails. The build kit is provided by Shimano with an XT drivetrain which will be a welcome sight for old school riders who prize reliability. The XT brakes need careful bleeding to meet similar expectations but they're great when they do work.
The Scalpel SE's geometry isn't the most extreme that we've ridden but will still make you want to ride both flowy and technical trails all day. A dropper post specced as standard helps when things get really hectic but don't believe the 'trail bike' hype as any Scalpel will always be first and foremost about speed.
Read more of our thoughts in our full Cannondale Scalpel SE 1 review.
Giant's Anthem has matured from an addictively feisty privateer racer into a more measured and controlled all rounder. We tested it with the latest Fox Live Valve automatic suspension, although there are more affordable analogue models now too.
While the Fox batteries and control boxes mean a middling 11.45kg mass, the actual Anthem frame is 250g lighter than before. Like the Santa Cruz Blur that's partly thanks to Giant swapping from a twin link (Maestro) design to a simpler flex stay set-up. We did find it collected some of that weight back in terms of mud collecting near the BB, but Giant says the shaping gives them 20% more pedaling stiffness.
While the Live Valve didn't always play ball, the basic bike is clearly well balanced and confident thanks to a 67.5º head angle and 450mm reach on the medium model. It's also naturally fast whether or not the 'sentient' suspension decides to open the shock and fork. Although the bike launched with Live Valve only, there's a manual remote shock version available now as well. Check you're getting the latest version, however, as the steeper angle Maestro suspension version is also available on the Giant website.
If this has got you tempted, check out Graham's full review of the Giant Anthem here
Cards on the table, I haven't actually ridden this bike and I normally refuse to write anything I – or other members of the Bikeperfect team – haven't ridden for Buyer's Guides. However it's essentially identical to the NS Synonym bike I have ridden, so I'm going to go out on a slight limb here and have a 'very good guess' at how it'll go.
The big win is that the Vitus is far cheaper than the NS. There is a fancy sub-11kg (claimed) flagship CRX version with RockShox SID Ultimate suspension and carbon wheels for £3,999. However, I reckon it's the CRS here that's the ultimate cut-price podium hunter. The SID Select fork and shock combo are excellent and proper racers will be stoked by the remote lockout for both. Rekon Race tires are FAF too and come set up tubeless for survivability.
Sure, the Deore groupset is a bit heavy, but you can upgrade if it ever wears out. The same applies to the DT wheels, but what we'd do is buy something cheap and very light (like Hunt's XC Race Wide) for racing, and keep the DTs as indestructible daily drivers. According to Vitus the whole bike still comes in under 12kg stock anyway, which is nearly 3kg lighter than the more expensive Trek Top Fuel.
The only thing you probably need to add is a dropper post, as the geometry is bordering on 'downcountry' with a 67º head angle at the end of a vast 500mm reach. That means most racers are probably best off sizing down, but if you want a super stable, ultralight marathon/epic ride bike then go long to, er, go longer.
The best XC mountain bikes: everything you need to know
What are the benefits of a full-suspension mountain bike?
On a smooth surface such as a fire-road climb or flat-out sprint down the start/finish straight, nothing is faster than a super-light hardtail like the ones in our best lightweight mountain bikes under 10kg guide. If you’ve got the skills you can skip and skim them through some pretty technical terrain, too.
When the surface gets relentlessly rough or there are big drops and rocks involved, however, full-suspension sucks up bike-stopping impacts to help you sustain speed. It also keeps the rear wheel more consistently connected for better technical climbing traction and cornering speed. In most cases, full-suspension mountain bikes for racing will have a remote lockout so you can turn them into hard sprinting pseudo-hardtails at the flick of a switch.
That’s why you’ll rarely see any of the fastest male racers on anything but full suspension bikes. That said, more of the top female riders still pick a hardtail – particularly on less technical courses with a lot of climbing – because they're generally lighter.
How much mountain bike suspension travel is best?
100mm is still the most common amount of wheel movement (travel) for race bikes. It’s enough to make a noticeable difference in control off drops and through rock gardens, but you still get to use the lightest possible front forks.
That said, there are an increasing number of race bikes – such as Scott's Spark and Specialized's Epic Evo – using 120mm of travel . If it's done right that extra 20mm really makes a difference on rough, technical sections. It rarely adds any weight to the frame of the bike either. And while 120mm forks are always a few hundred grams heavier, if the overall lap times are lower those extra grams are worth it.
Not all race bikes are adding suspension, however. Bikes like BMC’s TeamElite softail and Trek’s 60mm travel Supercaliber (with its ‘pump-action-shotgun-style' shock arrangement) have both won World Cup races this season.
What's the best XC mountain bike frame geometry?
The latest full-suspension race bikes tend to have slightly more ‘trail-style’ geometry such as 66 to 68 degree head angles for more stable steering. Top tube reach figures are growing slightly on some bikes to compensate for shorter stems, and increase confidence on more challenging courses.
But we’re still talking about race-focussed bikes built for close-combat responsiveness, rather than short-travel trail bikes for flat-out mountain descents. So while there are some 120mm travel bikes with identical geometry to 150mm travel enduro bikes, they’re not targeting the same sort of riding.
What are the best mountain XC bike components?
The more progressive riders on the circuit are also fitting trail-style components to their race bikes and we’re seeing that reflected in some off-the-shelf bikes, too. In terms of specifics, that can be as simple as wider handlebars (that you can trim down to taste) or enough space in the frame to run wider tires. Trek is the only brand brave enough to fit 2.4in rubber as standard on its new Top Fuel, though. Most of the latest short-travel suspension frames can also take an internally routed dropper seatpost, and it's becoming more common on XC bikes.
How much should the best XC mountain bikes weigh?
A sub 10kg (22lb) overall weight is the goal of most flagship XC full suspension bikes, but you need to throw a lot of carbon and money at most frames to get there. 'Downcountry' isn't helping either as some brands – including Trek and their Top Fuel – include short-travel trail bikes (weighing up to 15kg) in the XC category on their website.
That’s why it’s normally a good idea to look at frame weights to give you an idea of the potential outcome of any upgrade journey – or it would be a good idea if a large proportion of manufacturers didn’t massage their mass figures by not including shocks, axles, seat clamps, linkages etc.
That makes getting actual weights for bikes – take a scale to the shop if you have to – worthwhile when shopping. 11-12kg bikes are reasonably easy to find without completely emptying your race entry fund.
And if you do start upgrading to save weight, make sure you actually weigh the stuff you're swapping rather than assuming it's worth doing. Things like cassettes, or cheap carbon bars and seatposts can be massively heavy. in contrast some alloy kit we've weighed has been surprisingly light, so always do a full bike 'cost per gram saved' audit before starting to replace parts.
