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Giant Fathom Range Review

Giant Fathom Review


£699.99- £1,019.15

Finance from:

£74.92/month (0% APR)


Trail hardtail


MTB trail riding


12.4Kg (27.3Kg)*

Designed for the sort of trails that mountain bikers love to ride most, the Fathom is a great alternative to a full suspension bike.

2019 Update

The Giant Fathom now rolls on 29” wheels as well as 27.5” hoops. The three different Fathom models are available in both wheel sizes. The component selection is similar with both wheel sizes, although the 29ers have a 100mm travel fork instead of the 120mm on the 27.5” bikes.

Updated: 12th November 2018


With dialled trail geometry and a 120mm travel (100mm on the 29er) suspension fork, the Giant Fathom is one of a new breed of hardtail mountain bikes made for riding more challenging trails. Available with either 27.5” or 29” wheels, and three different component specifications, each Fathom model we review here features a high quality ALUXX SL-Grade aluminium alloy frame.

The Fathom is aimed firmly at trail riders who want to take on more challenging trails than traditional XC hardtails were designed for.  With short stems, wide handlebars, tubeless tyres and a dropper post this is a bike that is ready for some serious trail fun straight out of the box. Prices around the £1,000 mark make the Fathom an affordable alternative to a full suss MTB.

*Fathom 2 - Size M tested, no pedals

Giant Fathom frame


High-Quality aluminium alloy

A thoroughly modern trail hardtail, the Fathom frame features a slack 67-degree head angle (69-degrees on the 29er) with a long top tube and short chainstays. This gives the bike a confident feeling at speed and on technical trail sections. The OverDrive head tube allows for oversized headset bearings and a tapered fork steerer for improved steering precision and durability.

ALUXX SL-Grade aluminium is the highest quality alloy that Giant use fro their MTBs. This state-of-the-art material is made from 6061 aluminium alloy and delivers best-in-class strength-to-weight ratio. The tubes are formed and butted to keep things lightweight and deliver a high-performance ride quality. Internal cable routing keeps the lines nice and clean, while the low stand-over height is great for those challenging sections.

Unlike most other bike brands, Giant make all their frames in-house, so you can be sure of the best quality and value.

Giant Fathom Suspension


High-end SR Suntour forks

120mm of suspension travel extends the range of the Fathom 27.5 onto more technically challenging trails

With a 120mm travel fork, the 27.5” wheeled Fathom bikes are aimed squarely at technical trail riding. The 29er models have more of a cross-country focus with a 100mm travel fork. That said, you can ride both bikes confidently at trail centres.

All the Fathom models feature plush air-sprung SR Suntour forks. Traditionally Suntour are associated with entry level forks. However, recently Suntour have been upping their game with high-quality forks to rival the big hitters like RockShox. At the top of the range, the Fathom 1 gets a Suntour Axon LO-RC fork that features low speed compression damping adjustment, for a more efficient ride, alongside lockout and rebound adjustment. The Fathom 2 and 3 both feature a Raidon fork with adjustable rebound damping and lockout. The Fathom 1 and 2 both get 15mm thru axles for a stiffer front end.

Giant Fathom groupset


Wide bars, short stems and dropper posts

The trail ready component spec on the Fathom is perfect for fast paced fun on challenging tracks.

The Shimano SLX 1x11 speed drivetrain on the Fathom 1 is a real standout feature. With a single front chainring, one-by drivetrains are much simpler to use, with less to go wrong, and combined with a wide range cassette give you plenty of gear options for all the ups and downs on your route. Both the Fathom 2 and 3 have shorter 10 or 9 speed cassettes, but you still get a wide gear range thanks to the double front chainring.

Giant have put a lot of thought in to the components on the Fathom. It is great to see wide 780mm handlebars and short stems on every bike as this gives you more control when riding challenging terrain. A dropper post is fitted as standard which means you can make the most out of every trail section without having to stop and fiddle with your seat clamp.

Giant Fathom wheels


27.5” or 29er

Like the frames, the wheels on the Fathom are made in Giant’s own factory, so you can be sure that you are getting a top-notch wheelset for the price point. Most of the bikes get Giant XC-2 wheels, which are lightweight and have a cross-country focus. The Fathom 1 27.5” gets an XC-1 wheelset that features a wider rim profile that offers better tyre support when running lower tyre pressures.

It is great to see Maxxis tyres on every Fathom. The Ardent is a fast rolling tyre that is ideal for hard-pack riding but does lack grip on looser surfaces. Hard charging riders will probably want to upgrade to a more aggressive tyre like a High Roller, especially at the front. The wheels and tyres on every model are tubeless ready, so you don’t need to convert them to make the most of this puncture reducing technology.

Tubeless ready out of the box, the wheels are a plus point for the Fathom

Giant Fathom

Best for

MTB trail riding

Designed for the sort of trails that mountain bikers love to ride most, the Fathom is a great alternative to a full suspension bike. Ideal for trail centre loops, these bikes offer a confident ride on technical trails. Lightweight enough for efficient climbing the Fathom is versatile enough for long-distance cross-country adventures too.

If you enjoy the descents more than the climbs and want to get the most fun out of every trail section without breaking the bank, then the Giant Fathom is an ideal choice.

Giant Fathom frame detail Giant Fathom disc brakes
Giant Fathom brake lever Giant Fathom dropper post
Giant Fathom fork crown lockout lever Giant Fathom fork crown

Giant Fathom range models

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