Giant Fathom 29 2 review | Budget Mountain Bike of the Year contender

Giant’s Fathom 29 2 is the most affordable model in the brand's range and boasts a lightweight ALUXX SL aluminium construction with double-butted tubing for a strong and lightweight build.

An update in 2023 relocated the frame bosses, improving seatpost insertion. A 27.5in-wheeled version is also available, sharing the 29’s geometry and component spec with a different tyre choice.

The Fathom impressed us most with the speed and control with which it handles technical, chunky natural trails – thanks largely to the frame compliance, great fork performance and capable geometry.

Giant Fathom 29 2 frame details

The Fathom 29 2 boasts construction featuring Giant's lightweight ALUXX SL, primarily utilising 6011 aluminium shaped into modern, sleek tubes.

The 12x148 rear dropout spacing unlocks upgrade potential and the seatstays have an ovalised profile, elegantly converging at the seat tube, just below the point where the top tube connects.

Equipped with four sets of bottle bosses, Giant has strategically placed a pair under the top tube, removing any limitations on seatpost-insertion depth; a wise adjustment over the 2023 model.

Additionally, two pairs of bosses grace the top of the down tube, while another finds its place underneath.

The Fathom 29 2 gets a press-fit bottom bracket instead of a threaded version. The integration of internal cable routing entry ports on both sides of the down tube enhances the bike's clean aesthetic.

Cables exit underneath the down tube, just in front of the BB, and then travel under the rear stays to connect to the derailleur and rear brake caliper.

Notably, all cable ports are supported by rubber grommets.

Giant Fathom 29 2 geometry

Despite its size designation as small, my test bike was quite big, attributed to its extended top tube measuring 592mm and a relatively high 310mm bottom bracket.

The stack height also adds to the overall stature, at 622mm.

A 425mm reach and 1,154mm wheelbase, combined with a 66-degree head angle, move the bike’s geometry towards trail bikes territory and away from the world of budget mountain bikes.

Relatively stout 435mm chainstays keep the small-sized frame’s balance in check.

Giant Fathom 29 2 specifications

The bike features plenty of Giant-branded components, such as the Crest 34 RCL 130mm-travel suspension fork with an adjustable air spring.

It also has external rebound and compression adjusters to fine-tune feel further. Giant’s AM tubeless-ready 30mm rims, Contact handlebar and stem, Sole-O grips and a Romero saddle also feature.

A Contact Switch dropper post, with frame-size specific travel, gives a premium feel. Small and medium frames have 125mm of drop, the large 150mm and the XL 170mm.

The Shimano Deore 10-speed drivetrain has an 11-46t cassette, KMC chain and a 30T chainring (upgradable to a maximum of 32T because of close proximity to the shaped chainstay).

The whole size range sports 170mm cranks.

Tektro HDM 275 brakes with 180mm rotors provide the stopping power and the bike rolls on 29x2.5in Maxxis tyres set up tubeless, featuring an EXO-casing Minion DHF on the front and an Aggressor on the rear.

This build comes in at a respectable 13.8kg (size small) on our scales without pedals.

Giant Fathom 29 2 ride impressions

Boasting trail-ready geometry and equipped with trusted and aggressive Maxxis tyres, the Fathom 29 2 is poised to tackle all the challenges you’d expect affordable hardtail mountain bikes to handle.

Giant Fathom 29 2 climbing performance

Giant says the Fathom is balanced harmoniously to provide a powerful climbing position.

While I found this claim to be valid, at 5ft 3in, achieving the optimal position required nudging the saddle forward on the rails. This suggests there's still room for refining the climbing geometry for greater efficiency.

The tyres' aggressive tread pattern, while enhancing traction on natural trail descents, impeded the speed.

Whether this is an issue for you will depend on the type of terrain you ride; the Giant's ride is grip-rich.

Directly comparing the Giant to its competitors underscored its generally muted feel.

Several factors contribute to its exceptional damping. Slightly dropped seatstays and tube shaping play their part in the frame’s feel and reduce unwanted rigidity.

Combined with Giant’s wide rims, large-volume tyres and the fork, comfort was impressive.

The Fathom is enjoyable to climb on, largely thanks to the 75-degree seat angle, which improved pedalling efficiency.

The 30t chainring was a redeeming component paired with an otherwise hard-going 11-42t 10-speed Shimano cassette, helping me spin rather than grind up steep ascents with punchy rock steps.

The forgiving contact points contribute to a comfortable hardtail riding experience. While the push-on grips may be too large for some hands, they offer a commendable level of grip.

Giant Fathom 29 2 descending performance

The bike's dimensions, including a 425mm reach and a 1,154mm wheelbase, made for an ideal position when standing on the pedals for technical climbs and descents.

This ensured a perfect fit and enhanced manoeuvrability.

The additional effort required to ascend with the slower-rolling tyres becomes entirely justified when the descent begins.

Within the initial metres of the trail, it became evident I could confidently release the brakes and start having fun.

The Fathom feels incredibly well-balanced, and with the aggressively grippy Maxxis rubber, I found myself seeking out trail features to pop off, adding a thrilling element to the ride.

The first, natural, chunky trail I tested left me with a ridiculous grin across my face and an appetite for gnarlier riding.

The confidence-inspiring ride not only felt fast and fun, exceeding my expectations, but was also muted and damped, offering plenty of grip and control.

I was able to lay down what felt like faster runs, resulting in quicker descents on natural, technical trails compared to the other bikes in our Bike of the Year budget mountain bikes category.

The Fathom’s range of performance is impressive; swapping out the grippy Maxxis tyres for faster-rolling versions unlocked more speed on smooth, flowy trail-centre surfaces.

Once again, the bike's muted feel and 29in wheels played a pivotal role, minimising the jarring sensations that can stall less forgiving bikes or ones fitted with 27.5in wheels.

The performance of the Giant Crest 34 fork stood out, displaying responsiveness to subtle trail chatter and handling repeated hits from root steps and rock gardens with ease.

The fork's rebound speed and support throughout its travel were particularly commendable.

This combination of features, coupled with the affordability of the setup, positions the Fathom as a highly compelling option for those in the market for a capable hardtail.

How does the Giant Fathom 2 compare to the Cannondale Habit HT 1?

The Giant and Cannondale have contrasting weight and geometry figures.

Checking in at 13.8kg on our scales, the Fathom is 1.9kg lighter than the Habit, which made a considerable difference on the climbs and for manoeuvrability on the trails.

With a wheelbase of 1,177mm, the Cannondale is 23mm longer than the Giant. However, the Cannondale's shorter reach and top tube give it a more compact feel than the Giant when seated and standing.

Despite its larger reach, the Giant's slightly shorter stays (435mm versus the Habit’s 440mm) relative to the front triangle provide a balanced and controlled sensation.

While the fork quality is comparable between the two, it's hard to determine which performs better due to the Cannondale Habit's stiffer-feeling frame, which imparts a harshness the fork cannot fully compensate for.

Consequently, the Giant emerges as the more plush and comfortable option for riding across various terrain.

Giant Fathom 29 2 bottom line

Giant's Fathom 29 2 impresses with top-tier components, especially its Giant suspension fork.

Despite being £200 pricier, it justifies the cost with an excellent ride, performance and comfort.

With frame sizes running larger than the competition, you’ll need to consider carefully before buying.

Riders shorter than 5ft 3in, unfortunately, may find this Giant too big. But for anyone else, the Fathom 29 is a compelling option.