The Specialized Stumpjumper FSR Expert 6fattie is ready to rumble

It was just a few weeks ago that I was smitten by Specialized’s flagship S-Works Stumpjumper FSR 6fattie plus-sized trail bike – the copious grip, the cushy ride, the freakishly composed feel of those 3in-wide tires… and a price tag well beyond reach of most riders.

The second-tier Stumpjumper FSR Expert 6fattie is still a lot of money but with so few performance compromises made in the process, it’s akin to hitting the trail packing only a teensy bit extra around the middle the day after Thanksgiving – while having a fair bit left over in your wallet.

The Stumpjumper FSR Expert 6fattie boasts the exact same carbon fiber front triangle, welded aluminum rear triangle, and 135mm/150mm front/rear suspension travel (albeit with a slightly downgraded Fox rear shock and fork) as its top-end sibling. Naturally, the build kit is also subtly toned down, most notably with the aluminum (instead of carbon) Roval Traverse wheelset, SRAM X1/XO1 transmission, and Shimano Deore XT disc brakes.

The Specialized Stumpjumper FSR Expert 6fattie continues on with the company's long-running four-bar suspension layout

As a result, you get essentially the same great handling, proven suspension design, and tire traction features of the top model but with a bit of extra weight. Fully equipped with a bottle cage and Specialized’s neatly hidden SWAT chain tool and mini-tool, actual weight is just 12.92kg (28.48lb) – less than a pound heavier than the S-Works version and still remarkably light all things considered.

I’m just a few days into testing but so far, that initial revelatory experience is carrying over. Simply put, this thing is outrageously fun to ride. There’s incredible traction, it’s ridiculously comfortable, and most surprisingly, it’s proving to be silly fast with very noticeably reduced rolling resistance as compared with even top-end conventional trail wheels and tires, particularly on bumpier and rockier trails.

While many plus bikes come with low-profile tread designs to help with rolling speed, Specialized thankfully specs meatier tires for better grip

I have also noticed, however, that getting the tire pressure right on this plus-sized beast is absolutely critical. Too little and you end up with heaps of casing roll and uncomfortably vague handling; too much and you miss out on the traction benefits of ‘plus’ but still have to carry the extra rotating weight. That window is exceptionally small, too – just 1-2psi, and it’s conditions-dependent.

Further complicating that game is Specialized’s decision to spec such comparatively narrow rims on the 6fattie. Whereas other plus-bike makers are going with rims with internal widths of around 45-50mm, these are a scant 29mm and offer minimal support to the balloon-like tire casings.

So just how much stuff can you put in the SWAT box?

Ultimately, it’s a bit of a paradox that ‘plus’ is pegged as the ultimate solution for newer riders but that setup is so tricky, at least in this case.

That all said, now that I’ve got the pressure pegged for my local conditions (15-16psi here on the Colorado Front Range), it’s all systems go. Check back soon for a full review but given that I’m not exactly eager to give it back, be warned that this one might take a little longer than usual.

For more information, visit www.specialized.com.