Again in July, Specialised introduced the up to date Stumpjumper 15 carbon – As of in the present day, the alloy fashions have arrived. The Stumpjumper has all the time been a flexible path bike, and its newest updates together with elevated rear journey, adjustable geometry, and new Genie rear shocks have affirmed its standing as a top-tier ‘do something’ path bike.
Specialised has determined their carbon Stumpys ought to serve the higher-end market, whereas the alloy fashions supply lower-spec builds that come proper right down to entry-level costs. Nevertheless, the alloy bikes get the identical adjustable body geometry and suspension kinematics because the pricier carbon fashions. Two of the entire builds additionally include the brand new extremely adjustable Genie rear shocks Specialised debuted with the carbon Stumpys.
Stumpjumper 15 Alloy – Body Options:
The brand new Stumpjumper 15 Alloy frames are made out of M5 Alloy. Just like the carbon model, the alloy body’s entrance finish, rear finish, and hyperlink have been designed to make sure they work collectively to supply the quantity of stiffness Specialised supposed. Additionally just like the carbon Stumpy, there is no such thing as a longer a ‘sidearm’ on the alloy body. Specialised realized they might reinforce the hyperlink as a substitute, which gives a cleaner have a look at the identical weight because the outgoing design.
The Stumpjumper 15 Alloy comes with 29” wheels on S3-S6 frames, and MX wheels on S1 and S2 frames… besides the Fox Coil mannequin, which runs MX wheels on all body sizes. S2-S6 body sizes are mullet suitable by including aftermarket shock hyperlinks which keep the body’s geometry and kinematics with the 27.5” rear wheel.
Six geometry settings are potential between the body’s adjustable head angle and BB top, providing a variety of tunability to go well with totally different terrains or driving kinds. The top angle is adjustable by swapping out the headset cups. Impartial cups come pre-installed, and +/- 1° cups are included with every bike. BB top is adjusted by way of a flip-chip on the rear finish of the chainstays.
The up to date Stumpjumper 15 Alloy body does get Specialised’s SWAT down tube storage compartment. On the alloy Stumpys, the storage door is similar because the one discovered on the aluminum Stumpjumper EVOs. The brand new flush-mount door launched on the carbon Stumpjumper 15 wouldn’t work because of a distinction in tubing thickness. Specialised did say the amount of house inside is similar to the carbon fashions. A zippered software bag is included with every bike.
The alloy Stumpy frames get inside cable routing with entry ports on the down tube. Not like the carbon model, the alloy frames get routing for a rear derailleur cable, so that you’re not caught with wi-fi drivetrains solely!
Dropper put up journey numbers differ as Specialised shares totally different manufacturers on totally different fashions, however relaxation assured all body sizes supply sufficient room for ample size posts. For instance, S2’s come inventory with 150mm posts and S3s run 170mm posts. The Stumpy body accepts 34.9mm posts.
The frames additionally go away loads of house for water bottles. I reviewed the carbon Stumpjumper 15 Professional this summer season and the S3 body match a big bottle simply. Facet entry SWAT bottle cages are included on all fashions.
Different key fitments embrace Increase 148mm rear axle spacing, a 73mm threaded BB, and SRAM UDH-compatible dropouts. For body safety, the bike contains chainstay/seatstay guards, and a decrease down tube guard.
In the event you are inclined to hold bikes for the lengthy haul you’ll be glad to listen to Specialised now gives free lifetime alternative of all linkage pivot bearings to the unique proprietor.
Suspension:
The Stumpjumper 15 alloy gives 145mm of rear journey pushed by Specialised’s FSR linkage. Fork journey is 140mm on S1 frames, and 150mm on all others… besides the Fox Coil mannequin, which runs a 160mm fork on all body sizes.
Specialised strove to make sure the brand new Stumpjumpers would supply nice small-bump sensitivity, the vigorous experience you’d need from a mid-travel bike, and loads of functionality to soak up exhausting hits from tough terrain or huge drops.
The Stumpy’s FSR linkage was tuned to require little or no power to get into its mid-travel vary. In comparison with the Stumpjumper EVO, the brand new Stumpy will use 100mm of journey going through the identical quantity of impression power that will use 86 mm of the EVO’s journey. This preliminary softness goals to make the stumpy really feel prefer it has extra journey than it actually does (and after driving the carbon model, I’d agree it does accomplish this). The tune additionally ends in higher bump-force administration and considerably improved traction versus the Stumpy EVO.
To make sure wonderful pedaling prowess, the Stumpy’s anti-squat was fine-tuned to sit down proper between the earlier Stumpjumper and Stumpy Evo fashions.
Genie Rear Shocks:
Specialised’s new Genie-equipped Fox Float Efficiency rear shocks come on the Comp mannequin and alloy frameset. They aren’t included on the Fox Coil mannequin or the bottom ‘Alloy’ mannequin. It is a good time to level out that whereas the Genie shock was developed alongside the Stumpjumper, the bike can run different rear shocks.
For a full rundown of the Genie shock know-how, try my Stumpjumper 15 carbon launch article. Briefly, right here’s the way it works: The shock includes a distinctive outer air chamber, and Genie sleeves inside that slide forwards and backwards because the shock compresses and expands. The outer air chamber stays open for the primary 70% of journey, and with that added to the shock’s typical interior air chamber the additional quantity may give the shock a extremely delicate, coil-like experience really feel. Nevertheless, the spring price of the outer air chamber is tunable: By including spacers to that chamber, you may cut back the general air quantity within the shock and produce a extra supportive, vigorous experience.
What’s essential to notice is these changes solely have an effect on the primary 70% of the shock’s journey. At 70%, the Genis spacers slide over a set of ports and shut off the outer chamber. The final 30% of journey will get extra progressive because the air quantity within the shock is immediately decreased. Moreover, the interior chamber’s shock price is individually tunable utilizing typical eyelet quantity spacers.
Specialised has added an additional air quantity chamber to the shock with out utilizing a piggyback or distant accent, and so they’ve made it so each bottom-out resistance and the mid-travel vary you spend most of your time driving inside will be tuned individually.
Geometry:
Stumpjumper 15 Alloy frames can be found in sizes S1 – S6. The Stumpy Alloy’s geometry is strictly the identical because the carbon fashions.
Please notice: Because of the longer 160mm fork and 27.5” rear wheel on the Fox Coil mannequin its geometry varies barely from the opposite fashions, and it isn’t obtainable within the S1 body dimension. See Specialised’s web site for the coil mannequin’s geometry.
Specialised has taken the strategy of holding standover heights shut throughout their body dimension vary, so riders can select the attain that matches their driving type or choice. The Stumpjumper gives six sizes to decide on your ultimate attain from – The smallest S1 body is 400mm, the most important S6 is 530mm, and the sizes in between develop by 25-30mm every.
There are 4 totally different chainstay lengths throughout the six body sizes. The S3 and S4 frames share the identical dimension, as do the S5/S6 frames. Specialised stored the rear ends on the shorter aspect, which I’d say is appropriate for a ‘do every little thing’ path bike.
The Stumpy’s head tube angles are adjustable from a brilliant slack 63° to 65.5°, and the seat mast angles differ barely by body dimension however vary from 76.5° to 78°. The BBs experience fairly low at 337mm within the Excessive place or 330mm within the Low (besides the S1 body which sits 3mm decrease).
Mannequin Lineup:
The Stumpjumper 15 Alloy is offered in three full builds and as a frameset. In the event you drooled over the carbon Stumpys however discovered them a bit past your worth vary, you’ll be glad to see the rather more attainable fashions within the alloy lineup. Try Specialised’s web site for full construct specs on every mannequin.
- Stumpjumper 15 Fox Coil Alloy – $5,500
- Stumpjumper 15 Comp Alloy – $4,500
- Stumpjumper 15 Alloy – $3,000
- Stumpjumper 15 Alloy Frameset – $2,300
