Last week you saw pictures of the new 2011 SRAM XO group
in our coverage of Ashland's 12 Mile Super D race, but inside you'll finally be able to read my initial thoughts on the new 10 speed component group
and how it performed throughout the weather challenged time that I spent on it.Read on...Riding Impressions:
When SRAM introduced their top tier XX family last season it displaced XO as the no holds barred component group. While the XX kit is lighter, uses slightly more carbon here and there, as well as ceramic bearings, XO will still be the go-to grouppo for the majority of riders looking for lightweight and functional parts. The engineers at SRAM knew that while XX will be used on XC race and uber-expensive trail bikes, XO needed to be built to handle conditions from XC racing to rigorous All-Mountain riding. While I only had three days to gather my initial thoughts on the 2011 X.O. group, it gave me a good idea of the ins and outs of how it performed. The weather during the first two days was any drivetrain's nightmare, with a mixture of rain and snow that stirred up a gritty stew that managed to find itself into every nook and cranny on the bike, which was very convenient for testing purposes.
The 2011 XO group will be available with blue, red, gold, or black highlights
While the XX shifters have a lighter feel and take slightly less thumb effort to move the chain across the cassette, XO retains the positive and tactile solidness at the shifter that many SRAM users are fond of. There is a pronounced "ka-chung" to each shift that leaves no doubt as to how many gears you just dropped. I've always been a fan of this SRAM specific trait and now with an extra cog out back it makes even more sense. Shifting only needed the slightest adjustment to rein in a bit of cable slack as the new housing settled in, but was otherwise flawless despite the nasty trail conditions. For those who are convinced that having 10 cogs out back spells disaster when mud and grime strike, I'd argue that there seemed to be little to no noticeable difference between SRAM's 9 and 10 speed systems shift quality, even when the drivetrain was plastered in gritty mud. In fact, I even managed to bend my bike's derailleur hanger at some point bad enough that it was clear to see when viewing the bike from behind, but shifting performance remained excellent. Very impressive. Shifting to the large 36 tooth cog was as good as moving the chain up to 32 or 34 tooth cogs, quick and seamless. The tighter tolerances of the 10 speed cassette does mean that there is slightly more drivetrain noise than you'd find on a 9 speed cluster when things get dirty, but you have to listen quite hard to notice the difference. My test bike used a HammerSchmidt crankset so I was unable to put any proper trail time on the new XO carbon cranks, but stay tuned for a longer term evaluation of the complete group that will include the entire XO drivetrain and brakes.
A slightly revised cable pull ratio helps to keep the new 10 speed system running smooth
Three days surely isn't enough time to properly test these parts, but initial impressions are very positive. The new XO level 10 speed kit performed impressively despite the challenging conditions that it faced during the first two days. Although the XO family is no longer the premiere group in SRAM's lineup, it still performed every bit like the components that originally put SRAM on the map. My personal bike is now kitted out with the entire 2011 XO group with intentions of flogging it hard over the coming months. Stay tuned for a longer term review in the future!Keep reading below for more information on individual parts, as well as some great technical information!
The new carbon XO crankset
The sharp looking XO crankset uses new technology that forgoes the aluminum skeleton in favor of a lighter foam core. While the carbon arms have a similar (but different
) shape to the premium XX crankset, they are actually an entirely different beast altogether. Despite looking similar, the XO cranks use different materials and manufacturing techniques and are SRAM's first 'spineless' crankset. The new XO arms use a replaceable aluminum spider as opposed to the XX's one piece carbon unit. While this adds a few grams, it will allow riders to swap out the spider to allow the use of SRAM's soon to be released 24 and 36 tooth ring combo. Those who live in places where the trails head straight up, but still want to use the 2 ring system, will appreciate the new lower gearing. It will also be available in a three ring configuration that uses the common 64/104 mm bolt pattern.
Cross section of the XO crankset reveals where the carbon arm meets the aluminum spider
Just like the XX crankset, the new XO units don't make use of an aluminum skeleton that would add unneeded grams. If you were to cut your XO crankset in two you'd find that it is filled with a stiff and hard foam material. This internal foam unit is what the carbon is laid over as the crank is being manufactured, as well as being keyed at both ends to hold the pedal insert inline with the crank spider.
SRAM XO crankset details:
The aluminum pedal insert is keyed to fit into the stiff foam core
• Carbon composite crank arms
• Replaceable aluminum spider
• 2 ring options: 26/39 tooth and 28/42
• 3 ring option: 22/32/44
• BB options: BB30, PF, PF30, GXP
• Available in 170 mm and 175 mm lengths
• Color options: black, red, gold, and blue graphics
The foam core replaces the older versions aluminum skeleton to save grams
The XO crank will be available in BB30
For 2011 the XO crankset will have bottom brackets to fit pretty much any frame under the sun. Options include BB30, Press Fit and Press Fit 30, and the original GXP external BB. Total weights will range from 728 grams (BB30), to 788 grams for the 3 ring GXP option. In typical SRAM fashion there will be four graphics color schemes to choose from, including black, gold, red, and blue. The two length options will be 170 and 175 mm.
Destructive testing pushing the carbon crankset well past real world conditions. The result is a safe failure of the steel spindle long before the carbon arm or the bond between the two shows signs of giving up
SRAM uses destructive testing to find out not only when a part will fail, but also how it will fail. They know that anything can happen out of the lab and in the real world and knowing exactly how a part will give up is crucial in the design process. This was especially evident when they showed me an XO crankarm and spindle (Pictured above
) that had been pushed well past what a rider would be able to do. The crank spindle was clamped in place and enormous amounts of load were applied to the carbon arm. The result was a damaged steel spindle that twisted long before the carbon arm showed any signs of stress or the bond between the spindle and arm failed. The important thing to note about the test is actually how
it failed. The mode of failure would not have compromised the rider's ability to control the bike and the part never separated from the bike. This is called a "safe failure", as opposed to a failure that could have resulted in rider injury.
All of SRAM's 2 x 10 chainrings are designed to work specifically with their matched counterpart
The chainrings used on the XO crankset are designed to work together with their specifically sized mate. The two combinations available in the dual ring setup are 26/39 and 28/42 and the differences between the small and big rings are no coincidence. The gearing choices allow SRAM to place their ramps and pins in just the right spot to encourage the chain to move from one ring to the next. On top of carefully placed pins and ramps, the larger ring has a beveled inner surface that helps to guide the chain when it's going both up and down. The pictures below show the the large ring in various stages of production.
You can see the shift ramps taking shape on this ring early into it's production
Further down the line more material is removed and it begins to take shape
A nearly finished 2 x 10 chainring with it's ramps and rivets in finished
The new XO rear derailleur features some neat updates over older models
The new XO rear derailleur is not just a simple redo of the previous 9 speed version, but incorporates a number of smart updates and changes that will make it more reliable and user friendly. This includes limit screws that thread directly into the metal parallelogram as opposed to the older models plastic inserts that could be easily damaged. Further raising the reliability is SRAM's decision to no loner rely on C-clips to hold the bottom of the parallelogram pins in place. Some riders, especially those who spent a lot of time on tight trails, found that they were clipping the derailleur and dislodging the vulnerable bottom C-clips. This should no longer be an issue. The new 10 speed XO rear derailleur (as well as the XX model
) uses slightly revised cable pull ratios to move it across the 10 speed cassette, but this does mean that it is not compatible with previous years 9 speed shifters.SRAM XO rear derailleur details:
• 10 speed rear derailleur
• Available in short, medium, and long cage
• Exact Actuation Ratio
• Compatible with 36 tooth cassette
• Sealed pulley bearings
• Composite outer cage
• Black, red, gold, blue, graphics option
• 190 grams
SRAM's 10 speed XO cassette
One of the most exciting bits in SRAM's new 10 speed family is the XG-1080 cassette. While XX's machined steel X-Dome cassette is truly something to behold, the amount of time it takes to make the impressive unit rules it out when cost is factored in. It would be easy to mistake the new 1080 cassette for its more expensive sibling when looking at it from the back because of the unique construction that leaves the innards hollow. The difference is that the XO level cassette uses separate stamped steel cogs that are held together with short steel pins, as opposed to the XX versions nearly single piece construction. The result is a light 260 gram cassette that retails for much less than the XX model. Although it isn't available to the public quite yet, when the time comes you'll be able to choose between both 11-32 and 11-36 options.
XG-1080 cassette details:
The XO cassette uses an aluminum large cog likes it's more expensive sibling, but the remaining cogs are separate stamped steel units as opposed to the XX's slightly lighter one piece design
• New 10 speed cassette
• 11-32 and 11-36 options
• Separate stamped steel construction
• Aluminum large cog
• Aluminum lockring
• 260 grams
Avid XO brake details:
The new XO brake and shifter
• 333 grams with carbon lever blades
• TaperBore lever with integrated reservoir
• Aluminum lever body and caliper
• Tool free reach adjust
• Tool free Contact Point Adjust
• Black, red, blue, gold graphics option
Visit the SRAM website to see all of their goodies!
Day 1 and 2 at the Ashland Super D
Ashland Super D race coverage
Ross Schnell's trick Trek Remedy at the Ashland Super D