Specialized 2012 StumpJumper FSR Comp 29, Carbon Versus Aluminium Review

by FatBob on March 6, 2012

The 2010 Specialized StumpJumper received high praise from 29erOnline. We loved its 130 mm rear travel and its all around trail versatility - wrapped up in a moderate weight package. Since we first tested it, the StumpJumper has undergone some refinements. In addition, a carbon version has been added to the lineup. In truth, any excuse to get more time on a StumpJumper is a good excuse to me. Add some refinements and a carbon frame and I had all the excuse I needed to put in a request for a test bike.

We received not just one, but two 2012 StumpJumpers with the Comp trim. One Specialized Comp Carbon 29, which lists for $4,100 and a Comp 29, which lists for $3,000. The goal here is, not only to report on the changes made and the package that is the Comp, but also the difference between the carbon StumpJumper and the alloy version. It was very important to get the same parts on both bikes to make sure the comparison was as fair as possible.

Dueling StumpJumpers

Carbon has been one of the materials synonymous with high end in the bike industry for some time now. Early efforts at carbon fiber gave the material a reputation for great riding but also for being unreliable. Our experience from last year’s carbon Specialized Epic and various carbon parts has shown that carbon fiber has come a long way. So, why spend the extra $1,000 for carbon fiber? Is there a real benefit? Or, are we just victims of an industry trend, latching on to the next, latest and greatest? I am sure the answer is, partly yes to both questions. Our goal is to be able, not only decide what, if any, the benefits are, but also if the so-called benefits of carbon fiber are $1,000 dollars better or not.

alloy model with 400 gram pedals

weight with 500 gram flat pedals

To introduce the bikes I would like to go through the parts that are exactly alike first. Bars, stem and seat post are all Specialized branded parts. The setback seat post is a single bolt fastened to a curved square edged mount. Get the tilt on the saddles nose you like then adjust the forward or backward orientation by sliding the seat further or closer on the saddle rails. Pinch down the bolt with a number 5 allen key and proceed. The saddle is a Specialized  Henge saddle in a 143mm width. This is Specialized’s medium width saddle. Overall, it is a well liked saddle by a variety of rider types who come in a variety of shapes and sizes. The Henge has a good amount of padding and a flatter profile with a relief channel to add comfort and minimize the chance of erectile dysfunction. It is easy to move around on and it doesn’t get snagged on your shorts very easily - most likely due to its rounded profile. If you are a women and looking at this bike, I would recommend switching to one of the women's specific models Specialized makes. Our ladies love the Ariel model and it comes in three widths toaccommodate different sit bones and shapes.

Both our StumpJumper Comps are size Large. Realistically, we can squeak a 5'9" rider on at one end and up to a 6'2" rider on at the other end. Outside this range, we would need a different size. Related to fit, the stem is interesting. You can change the angle of it by adjusting a shim that goes between the stem and the steer tube. You can also run it positive or negative rise to get the fit you like. The only downside is that it is a bit heavy and the angles to work with are a bit extreme at + or - 8 to 16 degrees. It would be easier to use a tighter and less dramatic angle range. Still, by combining headset spacers, and riser or flat bar varieties, we can get most people to fit the bike to their comfort.

adjustable angle stem

The shock on the Comp model is a variation of the Fox/Specialized collaboration Triad shock. It does not have a Kashima Coating, but does have pro-pedal, open, and a lock-out setting that can be accessed from the saddle. I keep knocking it out of position when I reach to remove my water bottle on the Carbon Comp version. It will be interesting to see if the alloy version has more clearance. That bike was photographed, weighed and whisked off to Calvin so this test could get under way quickly. More later...

The big news about this shock is the proprietary feature called “auto sag”. All StumpJumper 29er models come with the Auto Sag feature. This “auto sag” feature takes much of the guess work out of setting up these StumpJumpers. Just fill the shock up to 300 psi, hit the auto sag air release valve, (also known as “the red one”) and cycle through the suspension. Then, press it again and your sag should be set. Just dial in the rebound, which can even be done while you are pedaling. Proceed at your own risk - just because you can, doesn't mean you should! My observation, so far, is that it puts me at about 20% sag. So, I view the auto sag as a reliable starting point. I am presently riding at 25% sag and I may get down a little further - closer to 30%. At 20% the ride is very firm and progressive through it's entire stroke. So, my recommendation is to start with the auto sag determined setting, ride the StumpJumper for a while, and adjust from there. Overall, I don't feel it is as completely dummy proof as some of the bigger magazines make it sound but it is a massive step in the right direction.

Triad feature

Another notable feature for 2012 is the switch from the 2011 model Rock Shox fork to the Fox 32 series 130 mm fork. Both are excellent forks, but the overall preference of the 29erOnline crew is Fox Forks. While talking with Eric Shuda from Specialized Bikes, I asked why Specialized went with the 32 series fork that had to be custom spec'ed to achieve a 130 mm travel range in the Evolution series instead of going with Fox’s  34 series. The simple answer seems to be weight. Remember that Specialized doesn't classify the StumpJumper line up as All-Mountain. It is a trail bike and, therefore, a bit more weight conscious. Specialized puts a high emphasis on keeping the StumpJumper as light as possible within it's intended purpose. This is a Trail bike that is extremely capable in the hands of an experienced rider. It was never intended to bash through obstacles and be ridden with reckless abandon. While certainly a sturdy bike, think finesse not brawn compared to the All Mountain designation.

The handle bars really stand out to me because they are wide and low. This is not uncommon. What sets them apart is that they bend backwards and flair upwards as well. In my mind, this is what makes a true riser bar. If you don’t like the width (730mm), you can always cut them down.

The drive train is mostly SRAM X7. As is common in the bike industry, the rear gets an upgrade to a SRAM X9 unit. The crank set is interesting. It is a SRAM crank with a 104 Bolt Circle Diameter that is set up for a 2x10 with a light duty bash guard. Take "bash guard" as more of a part classification than an actual mow-stuff-over endorsement. If you mow anything over, you will be disappointed with your bashed, bent up guard. Think of it more as a tidy guide ring. Again, think light weight, not brawn.

The wheels are Specialized Stout hubs with Specialized end caps that extend the surface area where it interfaces with the fork legs. Combined with the 15mm axle, the fork lowers promise to be plenty stiff. Rims are a Roval variety. To convert to tubeless, you will need to purchase tubeless tape, valve cores, and sealant. We have experience with these wheels on a few other test bikes, and have had zero issues with them in the 2 seasons we have run them. No, they are not the lightest or tightest but they are reliable and very good for the price point. The Purgatory 2.2 front and Ground Control 2.1 rear have been flawless in our wet winter conditions except for wet roots. Nothing works on them though. This is my go-to tire set up and we are working on making it our standard control tire set-up for the test bikes. In addition, the Control casings are durable, and set up tubeless better then any tire to date and with greater consistency, even as they get older. Specialized rubber gets a huge thumbs up!

Purgatory 2.25 front

Ground Control 2.1

Stopping comes from Avids Elixer brakes. The rotors are 200 millimeter front with 180 millimeter rear. They are very powerful. More on these in our final review. It’s hard to go without pedals and neither StumpJumper includes pedals, so make sure to budget in a set, or transfer your pedals over.

There are a number of notable, less obvious changes to the previous year’s models. The rear derailleur hanger has been changed and for the better. Instead of a hanger that bolts to the undersie of the frame where the 142x12 axle intersects the frame, the newer design bolts from the side - more similar to the traditional style of hanger. The newer system is much more refined and a welcome change. On the frame, the top tube shaping has been changed subtly, with the result being greater stand over clearance. The frame has internal cable routing for dropper seat posts. I did not take it on it's first ride without the Command Post Black Light seat post that is a must have for bikes I ride. We have 2 years service from the first version of the Command Post and have done no maintenance other than changing cables. For the bottom bracket, Specialized now uses a PF30 Bottom bracket shell. The PF30 bottom bracket uses press in bearings with plastic cups. This allows companies to make all carbon bottom bracket shells. To run GXP or Shimano, cranks you will need an adaptor.  Two companies (there are others these are two that seem readily available), Enduro and Wheels Manufacturing make adaptors for most varieties of cranks. It will be interesting to see if we can see benefits to this system over time. Lastly there is a chain device simply called the dangler.

Last among new features of the 2012 StumpJumper, is the 142x12 rear through axle. The 142x12 axle adds stiffness, and peace of mind, knowing the axle is threaded into the frame with a closed drop out. The phasing out of the old-style quick release axles is a welcome change and Specialized committed to it on all the high end mountain bikes they make.

Our goals over the test series include not only to seeing how all these changes make the bike compare to the 2010 StumpJumper we loved, but also we want to determine the differences between carbon and alloy frames. Please direct questions to the comments section. We will do our best to answer them all during out testing process.