Since 1981, Specialized's Stumpjumper has been a staple on the mountain bike scene. Now, celebrating its 50th year in the trade, Specialized is commemorating the occasion with the very latest edition, the Stumpjumper 15, and the brand says that it combines the benefits of big and small travel thanks to its new Genie technology.

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Specialized is pushing the fact that the Stumpjumper. This time round there's no Evo model but there is more suspension travel to fill the gap between the Enduro and the Epic 8 Evo. As such, the new Stumpjumper gets 145mm of travel at the rear and 150mm at the front.

2024 specialized stumpjumper 15 hero s.jpg, by Liam Mercer

While that might sound rather unexciting, the shock is very interesting because the brand has joined forces with Fox to develop the Genie shock. Specialized is no stranger to proprietary tech having worked on innovations such as Brain on its older XC bikes. 

Genie isn't without its claims and percentages, as it's claimed the technology ushers 16.3 per cent better bump-force management (the shock moves more, basically) than the outgoing Stumpjumper Evo. It's said to deliver a 57 per cent reduction in traction loss time and 39 per cent fewer severe bottom-outs compared to regular air springs. This has helped Specialized balance the benefits of both coil and air shocks.

2024 stumpjumper genie diag.jpg, by Liam Mercer

To achieve this, Genie employs two positive air chambers resulting in a large positive air volume for that coil-like feel. Then, inside the shock is something that Specialized calls the 'Genie Band' and as the shock dives deeper into its travel (70 per cent into its travel, to be precise), the Genie Band blocks the ports to the outer air chamber. The result is a significant ramp-up in progression throughout that last 30 per cent of travel. This is how the shock avoids harsh bottom-outs while retaining control.

As for the rest of the bike, it borrows much of what we saw on the Stumpjumper Evo. The Stumpjumper 15 benefits from Specialized's Fact 11 carbon-fibre frame which ditches the Sidearm design to reduce mass.

2024 specialized stumpjumper 15 fact.jpg, by Liam Mercer

That new frame also gets a redesigned Swat box. The Swat 4.0 is a sleeker solution that's flush to the frame with improved weather resistance.

The Stumpjumper 15 uses Specialized's S sizing system with six sizes on offer `– all of which utilise their specific chainstay lengths. With that, the chainstay stretches from 430mm on the S1 frame up to 445mm on the S6. Other figures include the 64.5-degree head tube angle and on an S4 frame, there's a 76.5-degree seat tube angle and a 475mm reach.

However, few of those numbers are set in stone as the bike benefits from a host of adjustment opportunities. The eccentric headset offers three head angle settings allowing riders to choose from 63-, 64.5-, and 65.5-degree settings. There's also 7mm of bottom bracket height adjustment. Through the use of aftermarket links, riders can then choose from a 29-inch or 650b rear-wheel, although the bike in S3 sizes and up ships with 29-inch wheels at both ends. S1 and S2 bikes are mullet-only for clearance reasons.

2024 specialized stumpjumper shock 2 s.jpg, by Liam Mercer

Specialized's new Stumpjumper 15 is available in five full builds. There's also an S-Works frameset on offer. All bikes get Fox suspension and SRAM AXS T-Type drivetrains and benefit from Roval wheels and finishing kits. However, there is a special Ohlins build that ditches the Genie shock for an Ohlin's TTX Coil shock.

Prices start at £4,000 for the frame only with builds starting at £6,000. The S-Works build tops the range at £10,000.

We managed to get some time on the new Stumpjumper 15 so if you're after some early impressions on Specialized's latest trail bike, check out our Specialized Stumpjumper 15 S-Works first ride review.

• www.specialized.com

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