It was no major shock to see Specialized unveil one of — what will no doubt soon be just one of many — of their new 650b (27.5in) bikes very recently. This means that for the time being at least, the Stumpjumper FSR EVO is available in all three wheel sizes.
Why? According to Specialized, the demand for the 650b-wheeled bikes, along with some of the benefits associated with the middling wheel size, were the key factors in bringing this bike market.
We took the new Stumperjumper FSR Comp EVO 650b for a spin to see just how this addition of 650b wheels pans out on the trail.
Frame and equipment: the right tools for a trail bike
Just like the 26in wheeled version, the new Stumpjumper FSR EVO 650b frame offers up 150mm (5.9in) of rear wheel travel which is also the case with the Comp – the cheapest of the Stumpy FSR line up – all controlled by a custom, Autosag-equipped Fox Float Evolution CTD rear shock. The FSR layout remains the same here too, with the shock’s lower mount connecting to the shock shuttle and letting it pivot on cartridge bearings rather than bushings.
The bottom bracket comes in the form of a press fit 30 and is surrounded by the ever so useful ISCG-05 chain guide mounting tabs. To boost rear end stiffness, Specialized have stuck with using a 12x142mm rear thru-axle. Interestingly, the head angle on our Stumpy 650b measured in at 68.4-degrees, making it pretty steep for a 150mm travel bike with wheels of this size. Chainstays measure in at 435mm (15mm longer than the 26in wheel version of the bike), while the wheelbase totals a reasonably short 1140mm.
Check out more of our Specialized 2015 coverage.
Ride and handling: nimble but predictable
Out in the hills, the Stumpy EVO 650b gets on with the job at hand with little fuss, and quickly proves itself to be a fun trail bike to ride. Laps at the trail centre or long stints on your favourite singletrack is where the Stumpy seemingly belongs. The new EVO 650b rides lighter than the 13.1kg (30.1lb) might have you think, and threading it along tight, technical trails can be done with relative ease in a confident manner while maintaining some decent speed. Geometry is well balanced, putting you in a good, fairly neutral position on the bike, making weight shifts rapid and effective.
Although it has what many would consider an ‘enduro friendly’ 150mm of travel at each end, when you do start to push things, you’ll soon find the limits of the bike. The RockShox Revelation is a good fork in the majority of situations, offering a smooth, supportive action, but plough it into a rough rooty section with harsh repetitive hits and it feels a little flexy and unsettled at speed, while the back end seems to work away quite contently. It’s worth noting that the pricier carbon version does use the stiffer RockShox Pike fork, which would certainly boost confidence at speed in more challenging terrain.
The relatively steep head angle does make it nice and nimble in the twisty stuff, but when you really are trucking, you’ll be wishing things were a little more raked out up front. We’d also switch the bars over for something with a lower rise too. Even with the stem dropped as low as possible, the front end still feels a little high. A couple of changes here – shorter, zero rise stem and lower rise bar – will make things feel a little more confident up front.
When it comes to the climbs, our medium sample provided just about enough cockpit room to make clawing up even the steepest trails a comfortable affair, but you’ll need to flick the CTD lever on the rear shock to help tame any pedal bob from the back end as you mash the pedals, especially at slower speeds.
On the whole, the new Stumpy EVO 650b is a good trail bike that you can flick and pick you way along technical trails, and although it won’t carry the same speed or pace as the 29in wheel version, it remains a lot of fun to ride.
|Name||Stumpjumper FSR Comp EVO 650b (14)|
|Brakes||Shimano Deore 180/160mm rotors|
|Rear Shock||Fox Float CTD Evolution with Autosag|
|Stem||Specialized XC 60mm|
|Shifters||SRAM X7 10-speed|
|Seatpost||Specialized Command Post Blacklite|
|Saddle||Specialized Henge Comp|
|Rims||Roval 650b 32H|
|Rear Tyre||Specialized Purgatory Control 2Bliss Ready 2.3in|
|Rear Hub||Specialized HiLo Disc|
|Cranks||Custom SRAM S-1250 double, 36/24T|
|Rear Derailleur||SRAM X9 Type 2|
|Handlebar||Specialized All Mountain riser 750mm|
|Front Tyre||Specialized Butcher Control 2Bliss Ready 2.3in|
|Front Hub||Specialized HiLo Disc|
|Front Derailleur||SRAM X7|
|Frame Material||M5 aluminium, EVO geometry with 150mm (5.9in) of travel|
|Fork||RockShox Revelation RC3 with 150mm (5.9in) of travel|