2011 Shimano XTR – Complete Technical Overview
When Shimano started work on the completely redesigned 2011 XTR, it wanted to expand the group’s appeal beyond it’s XC-racing history and offer a top-of-the-line group for all types of riders.
Given the growing variety of riding styles – All Mountain, Trail, Freeride or just plain ol’ classic Cross Country – XTR needed to expand it’s options to suit the varied needs of today’s riders. The XC oriented XTR groups ofÂ yesterday just weren’t what more aggressive riders were looking for. The freeriders rocking Saint groups still wanted something more high end, and so XTR has split into two sides: Trail and Race.
After talking to a lot of riders and sponsored racers, Shimano boiled their customers down to three groups: XC racers, gravity and “the rest of us.” The Trail group is really for that middle group called “the rest of us.” We still like to go fast, and we still want lightweight parts, but we want something that is designed to really handle anything we can throw at it.
THE CRANKSET AND GEARING
Debuting earlier this year on their XT and SLX groups Shimano calls their new DynaSys “a generational improvement thatÂ increases efficiency with a wide range gear ratio so you stay in a bigger gear longer with less energy loss to chain tension.” It’s a mouthful for sure, but versus a traditionally geared triple crankset, the benefits of DynaSys are:
24T = 10% reduction in chain tension overall versus 22T granny
32T = 30% reduction in tension in 32/36 versus 22/25 (both equivalent to a 0.88 gear ratio)
42T = 30% reduction in 42/36 (or reduced cross chain at equivalent effort)
How does that help? Read “more” for the complete breakdown of the impressive improvements on each component and the system as a whole…
Chain tension causes power loss through chain stretch, chain friction and unwanted suspension movement. On a bigger chainring, there’s less of an angle out on the chain going around the ring, which creates less friction. Most suspension bikes are optimized for riding in the 32 middle ring, so by making the big ring smaller and the granny larger, you’re bringing the gears closer in position to that sweet spot.
Plus closer gearing means less of a cadence change, fewer cadence recovery shifts and less momentum loss.
For the “Race” XTR double cranksets, the gear combos use a 12T difference with the exception of a pro-spec 44/30. Options for us mere mortals are 42/30, 40/28 and 38/26. The smallest of these uses the same crank arm as the triple setups, which means you can remove the outer caps off the big ring bolts and install a bash guard. You could also swap out and run three rings, but you’d want to switch front derailleurs as they’re optimized for double or triple ring set ups. You wouldn’t have to switch shifters, though, just change the setting on the left shifter.
The middle ring on the “Trail” XTR triple cranksets has titanium teeth with a carbon fiber reinforced engineering plastic base, and the granny and big rings are aluminum. On the double cranksets, both rings are aluminum.
Dyna-Sys also promises enhanced stability increasing the lenght derailleur like increase the length of the arm that the cable pulls on, which gives the shifter better leverage over the derailleur spring, leading to Shimano’s light action feel. It also means reduced cable tension, which makes shifting performance less susceptible to lousy cable runs or contamination.
In the photo above, you can see how the arm that holds the end of the housing and the lever that the cable pulls are both extend a good ways off the back of the derailleur. This, combined with the comparatively long throw of the shift lever, gives you incredible leverage when shifting. The result is feather-light shifting going up the cassette, yet it’s plenty snappy going to a harder gear, too. Yes, you have the push the lever a bit further than competing models, but it never feels excessive and the reward is the easiest, smoothest shifting we’ve ever felt. Seriously. Ever. And it’s just as good shifting up and down the chainrings, too.
Shimano also designed in a very linear level of effort required to push the lever across the entire cassette range. This means it’s just as easy going from the first (smallest) to second cog as it is going from the 9th to the 10th (largest).
When they introduced the DynaSys chain with XT and SLX, little attention was paid to the chain other than to say it was directional. With the XTR launch came the full story:
Rather than just use their 10-speed road chain, Shimano redesigned it for mountain biking to perform better in mud by removing a bit more material on the inside of the outer plates, giving more clearance for mud and gunk to fall out. For those worried about durability, they’ve reworked the rivet to be stronger than their 9-speed system. Lastly, the rollers and rivets are strengthened over their road chains to accommodate the higher shifting loads placed on MTB drivetrains. The HG-X chain is directional, like their road stuff, and the only difference between the SLX, XT and XTR chains is the finish, so this is where you could save some coin without affecting performance. Click on the images above to see the differences between their Dura-Ace (blue) and XTR (red) chains.
The key to the best performance of the system, of course, is putting the directional chain on in the right direction, a point Shimano really wanted us to drive home to you, dear reader. They said they see a lot of bikes with them installed incorrectly, which means you’re losing shifting performance. As Mark Weir put it eloquently: “If you put it on backwards as I did initially, it’ll shift like a dump truck.”
How do you know if it’s on correctly? You should be able to read the logo on the outside of the chain, right side up on the section at the top of the big ring. And all you cyclocrossers, take note: They do NOT recommend putting the MTB chain on the road drivetrains, and vice versa.
Another note worth mentioning: Shimano has done away with the quick link, instead recommending using a new pin whenever you need to break and repair your chain. They also recommend using a 10-speed specific chain tool if possible.
The new 10 speed cassette has “rider optimized gearing” that puts the additional gear in the middle of the cassette, where most people are going to be spending the bulk of their time. On the smaller gears, they’re the same range as the 9 speed cassettes, then you get a bigger cog on the top end. The top five cogs are ttanium, the other are steel. Technically, each piece shown here is its own part number in Shimano’s system, so if your bike shop’s favorite distributor decides to stock the parts, you’ll be able to order individual sections if you happen to bend just one of them or something.
One thing you’ll notice right away is that the top-end XTR cassette is about as different from SRAM’s fully machined, one-piece XX cassette as can be. In fact, it comes in eight pieces if you count the screw cap on the end. Shimano’s reps said that in it’s lightest iteration (meaning the “Race” 2×10 set up), the new XTR group is within 50g to 70g of the XX group, and most of that weight difference is in the cassette.
Even though you won’t see it when installed, there is some nice detail to the cassette’s spider. Despite the high number of individual pieces, during the press camp riding and subsequent racing on the group we haven’t noticed anything getting loose.
Besides DynaSys shifting, the biggest changes come with the brakes. Actually, it’s hardly fair to call them changes…these are completely new brakes from the ground up; levers, rotors, calipers and all. There are two different levers, the Trail (above) and Race (below) versions, but the calipers are the same for both.
As we cover the individual parts below, there’s one overall theme that played factored heavily in the redesign of each piece: Heat management. Shimano rethought the caliper, rotor and even the brake pads to reduce heat buildup dramatically, and the effect on performance is nothing short of amazing.
The Trail levers, which is what we rode and have on test, are designed to offer graduated leverage via Shimano’s Servo Wave lever design. The top image shoes the squiggly path within the piston body that dictates the amount of distance the plunger pushed into the piston. Even though power remains linear, the Servo Wave roller moves the pads into the rotors quicker at the beginning of the stroke all the way to pad contact, then gradually increases leverage (by slowing pad movement) to give you more power. In theory, to me anyway, this seemed backwards, but on the trail it works really well.
This not only lets the pads pull slightly further away when not in use (important just in case you bend your rotor), but it means the brakes start working quicker in those “oh s%$t” moments…not to mention giving them really good modulation once engaged.
The Trail levers also have tool-free reach adjust via the black knob on the outside of the lever, and there’s a tooled Free Stroke adjust that lets you set how much the lever will move before it starts moving the pads (you can see it better by clicking on the two bottom images to enlarge).
The Race levers are an exercise in simplicity. The piston body is super thin, there’s a tiny reach adjust screw inside the lever and that’s it. Like the Trail brake, the power is very linear, but the Race lever also has a very linear stroke feel since it lacks the ServoWave. The pads move equally with the lever movement, which Shimano says is favored by XC racers.
Both models get a new hose similar to Saint’s hose with a woven layer between two plastic layers to prevent expansion. Also, both levers’ pivot point is close to the bar, which maintains a good lever feel even when it’s pulled in close.
The calipers are the same for both Trail and Race models. Note the machined out mounting bracket.
The calipers have one-way oil flow, which limits the number of places that air can hide, and they’re made out of aluminum rather than magnesium to help further dissipate heat. Internally, the piston is ceramic rather than metal, which reduces the amount of heat transferred from the pads to the brake fluid. Calipers are now post mount only, no more IS options for XTR.
From there, Shimano started on the rotor.Â IceTech rotors use aluminum sandwiched between harder steel contact areas to run up to 100 degrees C cooler at the high end of braking activity, which should reduce fade. At that same level of braking, the finned ‘Radiator’ pads can reduce heat by 50 degrees C. The effect, they say, is like adding a rotor size without adding the weight of a larger rotor.
Click to enlarge and you can see the different layers of material within the rotor. The rotors are the same for XC and Trail. They’re a 2-piece design with an oversized alloy spider to save weight and improve rigidity, and the holes are designed to shed mud.
The last step in reducing heat was the brake pads…and they managed to shave weight, too.
What you’re seeing above is the Trail pad with cooling fins to further reduce heat. The Race versions look more traditional (non-finned), and there will be resin and sintered metallic pads offered in both versions.
The metallic Race pads have a titanium back plate to save weight, the resin Race pads have an aluminum back plate. The Trail resin pad has a full aluminum back plate with cooling fins,the sintered metallic Trail pads have an aluminum plate with cooling fins plus a steel backing plate for better strength. Race brakes will come with the resin pads as OEM and Trail brakes will come with the metallic pads, but you can swap them as you wish.
Does all of this effort to keep heat away work? We’ve been testing the Trail brakes with finned resin pads on the Downieville (CA) DH course and I rode three of the six days at Breck Epic on them down some blistering, lengthy descents. In every instance, they’ve provided plenty of stopping power with no noticeable fade and excellent modulation. Resin pads typically aren’t used for downhill or gravity-oriented riding, but for the all-the-way-up-then-all-the-way down of the Breck Epic’s course, these worked exceedingly well at slowing or stopping me on demand. So far, they’re very, very impressive.
Weight Weenie Bonus! All 2011 XTR brakes will come with a bolt (silver, in the bag) to replace the bleed nipple (black, on the caliper), saving about 10 grams on a bike. They’ll also come with a bleed tool (yell) for those that choose to do away with the bleed port.
There are three bits that make up the separate Race and Trail XTR groups. The first two are the brake levers and the cranksets. The last are the wheels. For the weight weenie cross country racers that want the full XTR experience, there’s the 1,480g Race wheelset. For Trail riders that want something that can take a little more abuse, there’s the 1,670 – 1,700g Trail set. Common traits are steel thru axles with the cones machined directly into them (reduces parts and weight). For the QR options, there’s a hybrid cone with steel surface at the bearing contact points, but alloy axles to save about 30g per wheel. They have a full lip seal with labryinth seal and have done away with rubber seal designs. Per usual for Shimano, the hubs use adjustable angular contact bearings, and they’re designed with Centerlock rotors in mind.
The differences are in axle options, spokes and rims, as follows:
The XTR Trail Wheelset, like the Trail brakes, get a little dark gold ano flair, in this case at the spoke nipples and front axle. Specs are:
- 559x21mm Scandium rim
- E-Thru 15mm front axle only
- E-Thru compatible 142×12 rear axle option (solid axle w/ replaceable nut)
- 14g butted spokes
- 1,670g per set with QR rear / 1,700gÂ with 12mm rear
You’ll notice there’s no 20mm axle option for the front. Shimano says that if it were offered, people would inevitably race DH on it and they’re just not made for that.
The Race wheels are all silver and dark gray with the following specs:
- 559x19mm Scandium rim
- Aluminum axles
- 15mm and QR front hub options (non-swappable)
- 15/17g super-butted spokes
- 1,480g per set
The comparison of the Trail (left) and Race rim widths.
Click to enlarge and check out the interior and exterior rim profiles. Both rims are tubeless ready and have no spoke holes so you can just mount the tire with some sealant and go. They work pretty good, too, because several of us at their press camp ended up (accidentally) running one or both wheels with no sealant. My front tire ran without sealant the first day and had no issues or leaks.
You may notice that there’s no 29er option…yet. They’re reviewing 29er wheel designs, but nothing currently available and nothing in the immediate future that they are willing to discuss. They do have an XT level 29er wheelset, though.
I’m going to admit it: It’s been almost 10 years since I’ve used an SPD pedal. I was tired of the mud clogging them up, the accidental releases and generally annoying performance. With these new pedals, I’m rethinking what to run.
Shimano’s new XTR pedal designs are slightly wider, which let them put the bearings wider and lower the profile slightly.Â This gives the rider a better platform, and engagement (particularly on the Trail model) is quick and effortless. Speaking of platform, the smooth, flat silver areas on the Race version are about twice as large as the contact areas on the previous model, which helps with shoe stability and a feeling of putting the power to the pedals. The Trail versions are even larger, which should work great with flat-soled or beefier all mountain shoes.Â They’ll also make it easier to just tool around town on your bike with regular shoes.
Both pedals are extremely low profile.
The Race model is not only lighter thanks to a slightly narrower spindle and ovalized outer housing, but the design should shed mud better thanks to the larger gaps around the spindle.
We got to ride both the Race and Trail models on alternate days, and my preference was the Trail model because of the bigger platform, but we’ve got the Race model on review and it’s been put through Breck Epic hell with no problems getting in or out of it, and no accidental unclips that weren’t easily attributable to my own errors.
Internally, the shifters now reel up more cable than older versions, which smooths out the shifter feel considerably. This, along with the changes to the arms on the rear of the derailleur are what gives the new XTR its easy, linear shifting.
Other than that, there’s not a ton new with the shifters save for refinements to the Multi-Release on the right shifter, which smooths out the double release of the release lever (shifts to a harder gear on the cassette). The changes mean you’re almost never going to get an accidental double shift, but it’s easy to do so when you want to. The lever’s touchpoints are slightly more rounded and dimpled, which are pretty comfy to use.
Overall, the 2011 XTR is an amazing group, and if you can get your hands on a set, you won’t be disappointed. We have yet to ride the 2×10 version (our test set is the Trail group with a triple crankset), but we should be getting the double in soon enough. And if XTR just isn’t in your future but you’re looking to take advantage of 2×10 and DynaSys, rest easy…we have it on good (anonymous) authority that 2×10 is coming for both XT and SLX.