On-One Carbon 456 XT Pro – First ride review

Top value carbon ride

Our rating 
4.0 out of 5 star rating 4.0
GBP £1,799.00 RRP | USD $2,964.76

Our review

A light, stiff, strong but amazingly comfy frame. Good value too
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On-One’s steel-framed 456 has almost become a legend in its own lifetime. Cheap, strong and versatile, it’s the weapon of choice for riders looking for a no-nonsense long-travel trail hardtail. Now it’s got a carbon cousin based on the same geometry but promising better ride quality and lower weight. The question is, is it worth the extra £300 or so?


Ride & handling: Low weight with big-hit ability

Long-travel hardtails used to be big, heavy and unwieldy beasts. They didn’t like being pedalled uphill much and, without a light touch, they were totally capable of pounding their rider to a pulp on the descents too. Not any more.

The Carbon 456 builds on the success of the original by taking tried-and-tested long-travel geometry, losing some weight and adding a dollop of carbon comfort. Although this is a super-stiff frame, the light build and inherent vibration damping qualities of carbon give this bike a lithe, agile feel that’s completely at odds with its ability to swallow boulders whole.

With 140mm of travel plugged into a chassis that’s incredibly resistant to twist and flex, it’s no surprise the On-One descends well. But the low weight and comfy vibration-absorbing frame also make light work of climbs, giving this bike genuine potential for all-day epics.

You can buy the Carbon 456 as a bare frame for £499 or fully built from £1,200. Our test bike is the range-topping XT Pro, kitted out with a full complement of Shimano’s genre-defining Deore XT groupset – right down to the wheels – and a RockShox Revelation fork with 140mm (5.5in) of travel. It’s a good value package that works well, even if the frame is crying out for a fork with a bolt-through axle.

The frame is stiff, but it has a light, agile feel: the frame is stiff, but it has a light, agile feel
Steve Behr

Frame: Like the steel 456 but 2lb lighter and with a more comfy feel

Metal frames use a bunch of tubes welded together and while you can vary tube shapes, diameters and thicknesses up to a point, a tube is ultimately a tube. With carbon there are fewer constraints. The designer can put material where it’s needed and remove it if it isn’t.

In the case of the 456 Carbon, the result is a frame that weighs at least 1kg (2lb) less than the steel equivalent, but still passes the tough new CEN standards for using forks with up to 160mm (6.3in) travel. It looks good too, with a smooth, sculpted appearance that belies its strength.

The tapered head tube houses a massive 1.5in lower bearing and there’s enough mud clearance at the rear to run 2.5in tyres in the thickest gloop you can find. Probably. Bolt-on dropouts make for an easy singlespeed conversion too.


There’s little to criticise, though we had some trouble adjusting our test sample’s headset and we prefer the steel frame’s fully enclosed rear gear cable housing. The carbon version’s exposed cables run along the seatstay and may need slightly more winter maintenance due to water and grit ingress.

The whole bike is kitted out with shimano’s deore xt groupset: the whole bike is kitted out with shimano’s deore xt groupset
Steve Behr

Product Specifications


Name Carbon 456 XT Pro
Brand On-One

Brakes Shimano Deore XT
Fork RockShox Revelation 140mm (5.5in) travel
Frame Material High modulus carbon fi bre
Front Derailleur Shimano Deore XT
Handlebar On-One Ultralight
Rear Derailleur Shimano Deore XT
Saddle On-One Bignose
Seatpost Thomson Elite
Shifters Shimano Deore XT
Stem FSA Gravity
Weight (kg) 12
Weight (lb) 24.9
Front Wheel Shimano Deore XT
Rear Wheel Shimano Deore XT