Last year at this time, the concept of a 27.5+ wheel size was littler more than a rumor – another feather in an already very full cap. In a very short period of time middle fat sizes have gone from ideas to full blown bikes. While the bigger companies have typically been more reserved when it comes to new sizes and genres, with 650b+, or 6Fattie as they call it, Specialized is jumping straight in.
After launching their 6Fattie dedicated hardtails known as the Fuse and the Ruze at Sea Otter, Specialized was quietly waiting to launch one of the first 27.5+ full suspension bikes as well. Given the fact that the 6Fattie uses the same Trail Chassis front triangle as the new Stumpjumper FSR which was just released, the fatter FSR had to wait for its debut. Now that the curtain has been pulled back, we got a chance to check out the Stumpjumper S-Works 6Fattie FSR in person and even get in an awesome ride in Graeagle, CA…
Even though the 6Fattie shares the same Trail Chassis front triangle as the standard Stumpjumper FSR, the 6Fattie is the only bike in the line up that makes use of a Boost 148×12 rear end. According to specialized, they weren’t sold on the benefits of the Boost system for standard wheels but the added tire clearance afforded by the wider hubs made it a good choice for the 6Fattie. Up front the bike again runs Boost 110×15 spacing with a Fox 34 Plus Factory fork set at 150mm of travel.
At the rear, the 6Fattie squeezes out 135mm of travel through the FSR 6-Pack linkage and a custom Fox Float Factory DPS shock with the Specialized Rx Trail Tune.
Built with a FACT 9m carbon front triangle and a custom 6Fattie M5 aluminum rear end, the bike has clearance for the Specialized 650b x 3.0 tires with room to spare, though these tires are mounted to 30mm wide Roval Traverse SL rims. All of the full suspension 6Fattie bikes roll on 29-30mm rims as opposed to wider rims on the hardtails. Because the front triangle is the same as the standard Stumpjumper, you’ll find all of the new features including full SWAT integration, and internal cable routing with captured housing that runs from the head tube to the front of the bottom bracket.
A welcome addition to the front of the bike is the new Specialized 6Fattie Purgatory Control tire which is quite a bit more aggressive than the 6Fattie ground control on the rear. Both tires are 3.0″ wide, 2Bliss ready, and 60tpi with a folding bead. After three days of riding in the Lost Sierras we were discussing the amount of flats on various bikes and compared to the mountain bikes with normal 650b and 29″ wheels, we’d estimate there were 10 flats on normal wheels and tires to every 6Fattie flat. That could be a total coincidence, but everyone, including the Legend Ned Overend, were riding the 6Fatties pretty hard.
When the new Stumpjumper FSR was introduced, one of the more interesting features was also one of the most commented on, with responses ranging from “awesome”, to “terrible.” After using the SWAT door storage system on both the 6Fattie and regular Stumpjumper FSR, our vote would be in the awesome category. After more than 3 years in the making, making SWAT possible was understandably more than just cutting a hole in the downtube. Specialized had to start with tooling they knew would probably be discarded in the end as they figured out how to create mandrels to make the inner walls as smooth as the outer and still allow for them to be removed. While the final design does add an estimated 100+ grams to the frame compared to a theoretical frame that was exactly the same minus SWAT, Specialized feels that the added convenience and lower center of gravity is completely worth it – and we’d probably agree. Combined with something like the Specialized SWAT bib liners and the SWAT equipped frames, riders can carry a full complement of tools, spare tube, around 70 oz of water, food, and more – all without a hydration pack. For anything other than the biggest rides, that should be plenty for most riders.
To access the SWAT storage simply undo the clip on the SWAT door, and then remove the door along with the bottle cage. Inside you’ll find two tool wraps which are the perfect size for a spare tube and pump, though that’s just the tip. Riders were stuffing anything from light rain jackets, to extra food, and even sandwiches in their downtubes. Yes, you’re adding weight to the bike, but that weight would otherwise be on the rider making for a higher center of gravity. Better yet, after 3 days of big rides none of the bikes we rode had any hint of a rattle from items stored in the down tube. Other SWAT integration on the frame includes the ability to run the EMT Top Cap Chain Breaker, and the SWAT multitool above the rear shock.
Available later this year, the Stumpjumper FSR 6Fattie will be sold along with the women’s version, the Rhyme FSR 6Fattie. Stumpjumpers will be available in the FSR Comp 6Fattie, Comp Carbon 6Fattie, Expert 6Fattie, and S-Works 6Fattie along with the FSR Carbon 6Fattie frame only. The 6Fattie Rhyme will be sold in the FSR Expert Carbon 6Fattie, Comp Carobn 6Fattie, and Comp 6Fattie models. The Rhyme will have an additional XS size though the rest of the geometry looks to be the same between men’s and women’s models with the exception of component sizing like bar, stem, and seatpost length.
First Ride Impressions:
I’ll admit that while interested in plus size tires and bikes, I was a little hesitant to hop on one while out in Graeagle, CA. Here we were starting around 6K feet of elevation and I’m about to ride with a bunch of super fast riders including Ned Overend and they hand me a 6Fattie? OK, then. Honestly though, after we started climbing out of camp towards the summit of Mills Peak there wasn’t one point in which I even thought to myself about wishing I was riding something else. The big tires climbed much better than they should, no doubt helped by the carbon rims.
After climbing around 1,900 feet, we reached the summit and prepared for the nearly 10 mile descent down Mill’s Peak Trail (if you haven’t ridden it, it’s worth the trip). Blasting down loose, decomposed granite trails, there were many situations where the added footprint of the tire was quite welcome. The added heft and rotational mass of the wheel and tires did take some getting used to – once they get going, really going, it can be harder to change direction quickly than on a regular mountain bike, but given the intent of the big tires in the Specialized line up, they seem to deliver a confidence inspiring ride at anything less than ludicrous speed. If you ask Specialized, they break the wheel sizes down like this – 650b is the most nimble, the 6fatty offers the most control, and 29 offers the greatest speed. I’m not about to give up standard mountain bikes in favor of 6Fatties across the board, but there is no denying the added control and confidence having those big treads underneath you provides.
Towards the bottom of the Mill’s Peak trail the tires really came into their own – especially on account of the weather and trail conditions. After a freak storm pelted us with hail, torrential rains made the remaining trail into a combination slip and slide and luge track. Even though I was riding with a number of shredders who normally could leave me in the dust, the fatter tires had me riding their rear wheels as they struggled for traction. To the haters of the half shell/goggle look, on this run goggles were a complete necessity.
Maybe the biggest takeaway from the ride, is that the 6Fattie rides just as well as the standard Stumpjumper FSR suspension wise, only with a bit more bite.