Earlier this year Specialized unveiled the 15th edition of the Stumpjumper, adorning it with fancy Genie technology and geometry adjustment but there was one glaring omission – an alloy bike. Today, the Californian bike brand has fixed that, introducing three alloy-framed bikes to the mix to complete the Stumpjumper collection.

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And the best bit is that each of the bikes shares a lot of the tech found on the carbon bikes, such as the downtube storage and the geometry adjustment. So that's both bottom bracket height and head tube angle adjustability, as well as the option to run either 29in wheels or a mullet wheel setup.

2024 specialized stumpjumper 15 comp alloy.jpg, by Liam Mercer

The big headline of the carbon bikes is Specialized's new Genie technology. It's essentially a dual-chamber shock design with a larger main chamber and a smaller secondary chamber designed to work in tandem – helping to provide a linear feel as the shock compresses. That is until it reaches the 70 per cent mark, where the secondary chamber is closed off, thus ramping up progression in that last portion of the travel. The idea is to achieve a sensitive but plush feel throughout the bulk of the travel without opening it up to harsh bottom-outs.

2024 specialized stumpjumper 15 alloy.jpg, by Liam Mercer

Genie is found on one of the alloy Stumpjumpers, the Stumpjumper 15 Comp Alloy as well as the frameset option. However, the Stumpjumper 15 Fox Coil Alloy introduces a coil shock.

The geometry of the alloy builds follows suit with the carbon models with an S4 frame getting a 64.5-degree head tube angle, a 76.5-degree seat tube angle and a 475mm reach. There's then a 435mm chainstay and a 1,244mm wheelbase.

As for the builds themselves, the Stumpjumper 15 Alloy welcomes RockShox's new Psylo Silver fork with  X-Fusion's 02 Pro RL shock, delivering 150mm and 145mm of suspension respectively. This model runs Shimano's Deore 12-speed shifting with Shimano BR-MT410 four-piston brakes and Specialized's alloy rims laced to alloy hubs. Those are then wrapped with Specialized Butcher and Eliminator tyres. There's also a TranzX dropper post with up to 200mm of travel.

2024 specialized stumpjumper 15 fox coil alloy.jpg, by Liam Mercer

The Stumpjumper 15 Comp Alloy benefits from the Genie tech with a Fox Float shock and a Fox 36 Rhythm fork. Shifting is provided by a Shimano SLX 12-speed drivetrain and braking is handled by TRP's Evo four-piston brakes. This bike gets Specialized's hookless alloy wheels and the same set of tyres as the base alloy build. There's also an X-Fusion Manic dropper.

Turning things up another notch is the Fox Coil Alloy build. As its name suggests, it boasts Fox's DHX Factory coil shock that's paired with a Fox 38 Factory fork. Shifting and braking are handled by the same kit found on the Comp Alloy bike but this one gets Roval Traverse wheels and a Deity finishing kit. The dropper post comes from PNW and the Loam dropper provides toolless travel adjust and up to 200mm of drop.

As for prices, they start at £2,750 for the Stumpjumper 15 Alloy and go up to £4,600 for the Stumpjumper Comp Alloy, and £5,000 for the Fox Coil Alloy. Framesets are not available in the UK.

• www.specialized.com

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