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Prototype SRAM BlackBox Derailleur and BoXXer Damper

Jun 6, 2013
by Mike Levy  
Another flashy new Blackbox item is this new drivetrain. This new DH specific Blackbox derrailleur is on it s second generation on Aaron Gwin s bike this weekl.

Prototype SRAM BlackBox Derailleur

Spotted on the back of Aaron Gwin's Specialized Demo 8 Carbon race bike today during practice for the Fort William World Cup, this prototype XX1-style derailleur is actually the second functioning generation of the concept. It employs the same 'straight parallelogram' geometry that sees it move straight across the cassette rather than at an angle, as well as the 'Type 2' clutch system that limits chain slap and the chance of derailment. While there isn't much info on the prototype at this point, it is safe to say that it also features a shorter P knuckle - the segment between the cage and parallelogram, similar to that of the standard X0 DH derailleur - that allows the upper pulley to track a tighter range DH cassette closer for more consistent action. The derailleur was only spotted on two other bikes: Steve Smith's Devinci Wilson Carbon and Sam Hill's Nukeproof Pulse. Is this a DH-specific prototype, or what we can expect the upcoming X01 derailleur to look like?


We've had nothing but good things to say about SRAM's XX1 drivetrain that we've been using for the last six months, but we also wondered how long it would be until SRAM applied the same principles employed in the XX1 derailleur to a downhill specific unit. After all, the XX1 rear derailleur concept was originally conceived purely for DH use where the bikes use only a single chain ring. The thought was that current rear derailleurs must also handle duties as a consequence of having multiple chain rings: that is, take up the extra chain slack, or allow for enough slack to shift up to the big ring. Eliminate those two jobs and the rear derailleur can be optimized strictly for rear shifting. That early prototype featured a 'straight parallelogram' that moved directly across the cassette, unlike the angled, 'slant-parallelogram' design found on all modern derailleurs. The slant parallelogram is necessary to keep the derailleur's upper guide pulley close to the cassette cogs while the pulley cage is busy trying to reel in and pay out excess chain as the front changer is shifted between chain rings.

Gwin's bike was also sporting a trick seven speed cassette that looks to use the same 'X-DOME' technology as the current XX1 unit, and it is hard to tell if the one on his bike isn't just a trimmed down version of a production XX1 cassette. The cassette uses an inner guard, quite clearly a one-off unit in the photo shown below, that helps to keep the chain from jumping off into the spokes on fast, rough terrain. It has been very interesting to see the progression of these downhill specific compact drivetrains over the last few seasons, beginning with
the six speed gearing pioneered by Jason Chamberlain and Brandon Sloan of Specialized for Team Monster Energy - Specialized in 2010. Yes, cut down cassettes are nothing new in the downhill world, but combining a smaller than usual chain ring with a pint sized nine or ten tooth cog, as well as the freehub that allows the system to run such a small cog, has changed drivetrains on the World Cup circuit for the better.


The DH sized cassette is also similar to the XX1 Cross Country variety.


Prototype RockShox BlackBox Charger Damper in the BoXXer

We were very impressed with the action of RockShox's new Pike fork when we first put time on it in Sedona, Arizona, earlier this year, with much of our praise being heaped onto its sealed 'Charger' damper. All of RockShox's current lineup, excluding the new Pike and the BlackBox BoXXer forks shown here that also use the Charger damper, utilize some variation of an emulsion-type damper - this refers to a layout where the damping oil is free to mix with air in the system. Open bath dampers from Marzocchi would fit into this category, as would RockShox's Mission Control damper that they use in their BoXXer and Lyrik forks, as well as FOX's Open Cartridge found in their Evolution series. In an emulsion damper air is used to compensate for damper shaft displacement as the fork compresses and extends. Oil does does not compress, meaning that the fork would not be able to compress if the leg or cartridge body were only full of oil. This design is often simpler but can mean that the oil and air can mix enough to cause the resulting air bubbles to pass through the damping circuits, resulting in a loss of damping and control. The opposite of the above, a closed and pressurized damper like the Charger system is completely full of oil and has essentially no air within it, meaning that there is far less opportunity for it to foam during hard use. It makes a lot of sense for RockShox to drop this type of damper into their downhill race fork given that this is the sort of environment where suspension is pushed to the max.

There s some new Blackbox suspension goodies floating around various pits here in Ft Bill as well. Some of if was tested recently in plain sight and nobody was the wiser. Pictured is Troy Brosnan s new Blackbox Boxxer with a prototype Charger Cartridge. This is an extended version of the same cartridge in the new Pike.

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But how does the damper compress if it is completely full of oil? In order for a closed damper to work, it must utilize some form of compensator that allows for expansion under compression - picture the internal floating piston (IFP) in the piggyback of a rear shock that pushes against the air trapped on the opposite side of the oil, thereby allowing for oil displacement. Rather than an IFP, the Charger damper uses an extruded rubber bladder to accomplish the exact same task, with the bladder expanding as the damper shaft travels into the cartridge as the fork compresses. Again, this isn't a new idea, but it is one that makes a lot of sense within a fork because a bladder does not present any of the friction and packaging issues of an IFP design.

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The photo above shows a Charger damper from a Pike fork, but the concept and layout of the version in the BlackBox BoXXer forks are likely very similar.




61 Comments

  • 88 3
 Ahhhh PB I love you today, so many good articles
  • 25 1
 It's a good day when darth vaders derailleur has an article
  • 37 0
 I want to see 6 or 7 speed go standard for dh, and un turn the spoke flange on the hub can move out, making a sturdier rear wheel.
  • 10 2
 Already made my own, machined a back spacer out of aluminum and use the lower 6 cogs. Been doing it for 3 years now.
  • 8 2
 It would be cool if they started building hubs with the same overall width but a shorter cassette body that allow for flanges to be equidistant from the centreline. It would make for a laterally far stronger wheel build and even spoke tension. I would have thought a 135/142x12 using this method be just as stiff as a 157/150x12 using current methods. So why have they not done this yet?
  • 10 0
 I don't really ride DH myself, but that seems like the way to go. I think 150mm hubs should have 6/7sp freehub bodies, and 7sp 11-28 cassettes with 10sp spacing. That way you could use standard 10sp shifters and derailleur with the lower cogs limited off.
  • 8 0
 exactly why would I need 11 speeds on a dh bike. In my gambler there is a 10 speed casset and the difrence between neighbour cogs is so small that i need to shift at least 3 cogs to feel THE difference. Plus the chain is super tight between cogs. I want to see stock 7 speed system!
  • 22 0
 On the original parts that Specialized prototyped for the Monster Team, we had a dedicated 7-speed cassette body with wider hub flanges. You can actually put the spokes WIDER with a 135 7-speed than a 150 9/10-speed.

What we found is that with the high quality modern rims and spokes, the wider flange stance was not needed. Standard spacing worked flawlessly with never a taco'd wheel. The bigger problem with DH racing is flat spots and rim dings.

But in theory you are right - wider is better.
  • 2 0
 I would try to make a gearbox and try to catch the weight as low as possible (i think the weight wouldn't be much higher after all), can be integrate it into the rear hub or center of the bike. A rear deralleur can be easily trashed down in a crash which wouldn't be with a gearbox - so i believe it will be much more responsible to go with. I think it is important not just for the racers but for the average riders too, to tell the truth i don't care if my bike weight 500-600 gramms more, if my bike is fully fit and forget. No one likes to service his forks and shocks every 2-3 months - even the max before service time is about 1 year (for example open bath forks), i would be pretty happy if this service times comes after every 3 years, and in this time it would be absolutly careless, while i can enjoy my riding all of the time. Anyway it is good to see Downhill bikes still upgrading and parts getting better and better over time (i just don't like the theory to get the weight down too much as these parts will snap in half of the time than the previous models did for example my 2006 Marzocchi 888 rc2x still happy and working just like i bought it, no sign of wear down - i know you must sell these parts but make up to performance instead [better damper, better seals, better stanchion tubes, better bushes etc...] don't sell overpriced parts which will fail in no time...)
  • 1 0
 I thought Gwin was going to be on Fox and Shimano? Is this his bike, or Troy's?

My mate's bike has a proto 9 speed cassette with only 7 sprockets (9 speed spacing I mean) and a hub with no dish. I'd rather run that than a 7 out of ten block with a massive waste of space between block and spokes.

I agree with you hellslayer about the forks. I've got a marz DJ which needs servicing pretty much never, and a Totem air which needs doing every 5 hours to keep it sweet
  • 2 0
 Gwinn id on fox sudpension and sram everything else, he wanted to keep fox so they did
  • 1 1
 And the bike in the shots has rockshox forks, so it's not his yes?
  • 1 0
 My 7 speed set up, no mods just spaced out

www.pinkbike.com/photo/9057427
  • 2 0
 Troy Brosnan's bike
  • 1 0
 A mate of mine used a hope pro ll trials rear hub and fits 5 8speed sprockets on it. Paired with a 36t front chainring, he gets around just fine. And gets a heap more engagement points because its the trials hub not the standard pro ll.
  • 21 1
 Keep up the XX1 development. I am eagerly awaiting the trickle-down products!
  • 12 8
 Or better yet, actually design something progressive that eliminates the weakest link on all modern mountain bikes: the lightweight 200 gram contraption with vulnerable linkages that hangs off the right side of the rear axle, waiting to be destroyed by rocks, roots, branches, and crashes.

I wonder if Sam is missing that 9 tooth cog he used to have? This is not progress, just another distraction from progress.
  • 8 2
 And who says money can't buy happiness3
  • 39 0
 people who dont know where to shop
  • 9 0
 Poor people
  • 6 0
 at first i thought it said, "new dampened BlackBox Derailleur"
  • 2 0
 Basically, this non-slant parallelogram design rear derailleur is made to reduce the effects of bumps having a negative effect on shifting. With a standard slant parallelogram design, any bumps that jostle the rear derailleur will cause it to move up the cogset to larger cogs. Even though the spring will bring it back down, this could happen at an inopportune time causing a misshift or jumped cog. This non-slant design eliminates that particular problem and stabilizes the RD somewhat.
  • 1 0
 Thanks for explaining that! Never thought about it. I've once destroyed almost all spokes on the drive side and the derailleur when going over some bumps at very high speed, it snapped the limit screw right off and sucked it in between the cogset and spokes, tearing everything apart. Will definitely upgrade to this when it becomes available in 1-2 years hopefully Smile
  • 2 0
 Only been asking for this RD and cassette for about 7 years, been cutting down Sram cassettes for ever as well, though no way am I taking a hacksaw to my $600.00 XX1 cassette, us poor people who work for a living cant afford that chit, nice for Gwiny!
  • 2 0
 SRAM, Shimano, please make it stop. External gearing and mechs are not good for off road riding. They remain exposed and vulnerable to destruction. Inboard Gearboxes. (or resurrect something akin to the Hammerschmidt-retrofit capable) Please.
  • 1 0
 I notice that specialized runs those derailleur guard things that attach to the rear axle. This would prevent your d hanger from getting bent. However, isn't the whole purpose of the hanger is to bend and break in impact, so there is less stress on the derailleur?
  • 6 3
 Looks like something quite close the the Shimano saint... But.... I'm more of a sram guy myself..
  • 3 0
 i want to buy the other black box stanctions from danny harts bike are those available yet
  • 2 0
 free BlackBox shit is really the best reason to change drivetrain sponsors. yet still keep the fox 40. well played aaron, well played.
#gwinning
  • 3 0
 He probably switched to SRAM cause he was pissed about what happened with his brakes at Worlds last year.
  • 1 1
 well done rockshox you have taken another step backwards, and letting your competition exceed you further.

ported damping is a massive step back and then not using a pressurized cart to help prevent cavitation? bad bad move.
  • 2 0
 Sram: The moment you make a 7 speed shifter to it, I quit internet, my soul will be at peace
  • 1 0
 I would think less gears the better for strict DH use. Less gears + wider hub flanges = stronger and lighter rear wheel
Oh, wait.......that wouldn't be marketable.
  • 2 2
 The XO1 is coming out this fall and I'm sure an X9 version is coming out next year. Wonder when Shimano will take a crack at a system like this?
  • 6 4
 Saint is their dedicated DH clutch-equipped derailleur system. You can easily run it with fewer than 10-speeds with slightly longer limit screws.
  • 2 0
 Boxxer charger damper? Yes please!!
  • 3 1
 I'm more impressed by the heat colouring on Gwins rear rotor.
  • 1 0
 Must be nice to be fast enough where people try new technology on your bike...for free!
  • 1 0
 so the sram deraillure is like a crappy version of the shimano xt deraillure(not xtr the xt is compliment enough)
  • 1 0
 Personally I want a 39 geared DH drive train..........yeah, that will win me world cups!
  • 1 0
 I want dat derailleur Drool Awesome stuff.
  • 2 1
 Just looks like a DH specific Sram clutch mech!
  • 4 4
 I'd just like to purchase a 9-speed clutch derailleur. Seems they are only available in 10-speed, and apparently 7-speed.
  • 4 2
 Get a 10-speed 11-36 cassette and a 10-speed clutch derailleur, then block off the 36t cog.
  • 3 0
 Obviously. However, the point is that I don't want to replace my entire drivetrain (cassette, shifter + cable, chain) for each of my bikes.
  • 4 1
 You can run a 10-speed derailleur on a 9-spee drivetrain.
  • 4 1
 There is a way to do it. A combination of a shimano detailer and any 1:1 ratio shift pod. There is an article about how to do it. Think it was on Vital website.
  • 2 0
 Apparently (do some searching) but the only thing that will work is a 9 speed cassette, 9speed chain, 10sp shimano (eg Zee) with a 9 speed sram derailleur. The only way for it to work is the pull ratio has to be the same. The shifter is what makes the derailleur stop at the correct location on the cassette. I haven't tried but that is the word going around.
  • 2 0
 + 5mm spacer. Getting pretty hard to find a zee rear mech right now though. Then get the shimano 9 speed 12-36 cassette and put an 11t on it.
  • 1 0
 That looks like a good old FIT cartridge.
  • 1 0
 is it possible that rs actually has a non half-assed damper?
  • 1 0
 Bladder you say... Smells like Marzocchi 05'
  • 1 1
 Sram is the shit i will sell in my shop____________0^0___________
  • 2 2
 I can already tell, these parts will suck
  • 1 2
 i was under the impression gwin was on shimano????
  • 1 0
 he was last year. but not any more
  • 1 0
 last year he was, but now he is on sram. Anyway he's still on fox suspensions
  • 6 0
 Why don't Racers use Avalanche Racing cartriges They are better And custom tuned,not to mention have been in the buisiness with moto -essentially this black box one is prob a bit lighter ,but does it have the blow off recirculating feature - out of all the suspension ive tried nothing can match that of 03 Monster t the plushest.for single crown applications Rock shox wins with there Totum coils -that can be made even better by insalling Avalanche internals.
  • 1 0
 because avalanche is overhyped and support would be nothing at races compared to other brands
  • 2 3
 Personally I don't see why we need 11 speed drivetrains on downhill bikes

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