Now Reading:

The story of the SRAM XX1 drivetrain

The story of the SRAM XX1 drivetrain

Billy Thackray Billy Thackray



SRAM invited a load of us to have a snoop round their European headquarters in Schweinfurt, Germany the other week to see the wheres, hows and whos concerning the development and testing of the XX1 drivetrain. Victor Lucas was in attendance with his camcorder and made a very nice film about the place and what went on. I look like a bit of a tool I know, but try to ignore that and focus on the what the professionals are saying about this 11 speed bit of kit. We’ve previously ridden the XX1 out in Whistler and we’re quite impressed by it’s performance.

We’ll be letting you know more of our thoughts on the XX1 and how it survives after a Winter in the thick Welsh mud at the Dirt office trails.

Us lot having a snoop round SRAM HQ in Schweinfurt.

One of the SRAM testing labs. Clean isn’t it?

The machining stages of the XX1 rear cassette.

Design Engineer Matthias Reinbold tells us how the cassette goes from a big lump of steel to the precision engineered final product.

Cut away of the XX1 cassette.

Frank Schmidt (SRAM development group leader) on the attributes of the XX1 chain ring.

Engineer Robert talks about the X-Sync rear mech.

Test engineer manager Markus Klier gives us the lowdown on the deMONSTRator test rig.

Markus talks about the XX1 shifting performance tests.

The wheel durability test.

The Liteville 301 (aka the Ball Chopper) kitted out with the new SRAM XX1 clobber that we’ll be testing. We’ll let you know how we got in a future issue of the magazine.

Photos: Sebastian Scheick.

Featured in this post

  1. Ralph

    Look at the ‘BIG’ chainring… shouldn’t these be the other way round!? : P

  2. andrew

    Looks rad!

  3. Nick Hamilton

    I tell you what… the victor lucas is bloody handy with a camera… and can put a sweet edit together and all!

  4. Hancock

    I still don’t get why they won’t just sell an 11-40 nine or ten speed cassette?
    I’m not a roadie, if you’re reading this you’re probably not a roadie either, I don’t give a crap about cadence management. I just want a fast 11t gear for down, a slow 40t for up and a couple of ratios in the middle for stuff that’s not up or down.
    Seriously, is it that hard to design a cassette with some nice big gaps between the ratios?
    While you’re at it Sram, how about some of those chain rings in a 104mm bcd, separate those good innovations from the proprietary bullshit and I’ll go buy them.
    Tl:dr, the mech, chain rings and wide ratio cassettes look ace, but SRAM are putting to much other crap around the good ideas.

    1. arthurk

      Hancock, for efficient shifting, the rule is one cog must be no bigger than 110% of the next cog, so if you had a 9 spdcassette with 40t max, it’dhave to be a 21-40t and 10spd would be a 20-40t. You get the gist

      1. Hancock

        At the risk of being rude Arthurk, that’s a load of marketing bollocks.
        If you look at five/six/seven speed cassettes you will find that the jumps on those are more than 110%
        The five speed on my commuter goes in 25% then 30% jumps, it shifts flawlessly, smooth, quiet and has been for more than a decade (although not the same cassette all that time).
        The 110% business is to do with cadence management, which is very important in road or cross racing.
        It’s largely meaningless to mtb riding, having a correct gear ratio that allows you to keep riding is more important than having 8% steps that allow you to maintain a precise cadence and power output.
        There is no engineering reason why you can’t have a wide ratio nine speed cassette. If you want to test it, you can take the small gears from a road cassette and the lowest ratios from a mtb cassette and mount them on the same hub. That’ll give you a jump far bigger than 110%, bigger than 130%, it’ll still shift just fine.
        Unfortunately what manufacturers tell customers often has little to do with engineering. When a company says something is impossible, what they frequently mean is that they didn’t even consider it.

    2. Taylor

      Im with you man. I usually skip shift anyhow. Skipping at least 1 if not two everytime i shift. Thats bith up and down.

  5. DrippyHippy

    when do we get the trickledown in the lower end groupsets? c’mon you guys know surely

  6. arthurk

    Hancock, for efficient shifting, the rule is one cog must be no bigger than 110% of the next cog, so if you had a 9 spd cassette with 40t max, it’d have to be a 21-40t and 10spd would be a 20-40t. You get the gist

  7. mad_homer

    maybe you are not totally wrong but at my father cannondale commuter with shimano nexave groupset there is a 8 speed cassette with 11 – 36 tooth ratio. May what Hancock requests is a setup that would not shift superbly but offers the ratio.
    the engineering bits and pieces from sram look ace but to be honest the main intention is to sell new stuff. It was clear that they would have to offer 11 instead of 9 or 10 because that’s already there. So comparing to the competion they seem to be ahead simply because it’s 11.
    For me it’s clear I will not buy in because of incompatibility with other drivetrain parts. maybe you don’t need to by the cranks and the chainring up front (which really is ridiculous after all the 104mm pattern is pretty accepted!) but you definitely need to by shifter, Hub (or free body if you own I think DT or Hope for now), cassette and derailleur.
    To make it clear, there is no technical reason why the xx1 parts have to incompatible with other sram or shimano parts. It’s only reason is to avoid the endcustomer to find it’s own most effective way through their offering and to avoid mixing sram parts with competition.
    I would say wait until the new zerode trailbike gets out and get it with alfine 11sp hub. then you will stop thinking about drivetrain. which results in mentally freedom…
    by the way you can even ride your bike uphill with a 9sp 11-36×33 setup and also downhill and it’s not perfectly light and not shifting like a dream but it’s reliable and durable and cheap.


  8. Gor

    well, isn’t that nice, to start your morning by listening to some engineers with such a lovely German accent!

  9. mattjevans

    I’m with Hancock, practically all of the benefits of this system could be achieved for the average 1×10 rider with a 12-42 10 speed cassette, admittedly with 104 BCD front ring the smallest you can go is 32T but I don’t see that as all that much of a limitation

    Personally I think a company releasing a 42 tooth shimano 10 speed compatible cog, or even selling a modified cassette, could do a good trade. If I had any mechanical skills I’d be doing it myself

  10. mattjevans

    Thinking about it properly obviously it has to be at least a half cassette, you need to replace all the large size cogs from 19 to make the gaps smooth enough

  11. Down n Dirty

    Not related to the above topic.I was wondering if the Achive footage on the video section on the site is down,as i cant seem to view the videos from times gone by.here is a example it might be my browser,can some one hit this link and see if it works for them please http://dirt.mpora.com/uci-world-cup/sam-hill-andorra-crash.html

  12. Big Al

    I think the point of it is, is weight. You have a 1×11 with a good spread of gears, but you also have a single ring upfront that doesn’t need a chain device. Straight away that is 120 grams saved over a 1×10. The other thing is the rest of the kit is as light or lighter than what is about now. It’s an upgrade from 1×10. Simple as that.

  13. Andy

    The video just seems to be a great big advert for SRAM. Shame since the xx1 appears to be a useless bit of tat!

  14. Paco Loco

    I agree with Hancock.
    All the features of XXI are pretty good but they don’t need to be mutually exclusive. They could release a 10 speed casette with that spread and make a lot of people happy, but they want to sell you a whole groupset not just a casette.

  15. Paco Loco

    This is how I see it: a hell of a lot of riders (not just DHers) are moving over to a 1-by-whatever setup on their bikes as they realise they don’t actually need multiple chainrings. For gear manufacturers this is bad news, since people now need only half the components – no front mech, shifter, or multi-chainrings required any more.
    So how do the manufacturers continue to extract the same amount of cash from people who actually need less bits from them? Simple – they make up all this “special” XXI type stuff which costs even more and is not compatible with any existing stuff.

  16. Neil

    Or maybe they just decided to make the ultimate, no compromise, single ring drivetrain without worrying about cost. I’m not going to buy it, but only because of the price, it’s not hard to imagine how good it would be to ride. I can’t imagine they’re expecting to sell that much of it straight off, but once the prices come down, or it filters into lower groupsets you’d have to think people will get on board.
    Would be great to see some of it made for 10x too – can’t see why they couldn’t make a version of that chainring for current drivetrains for instance. I’d buy one.

  17. Kevolution

    The shifting test doesn’t account for dirt ingress into the system. So the test is inconclusive for real world use of the system.
    Once again, the end user becomes the test pilot for durability.
    I replaced so many SRAM components that promised so much over the last 7 years, my default setting is skeptical.


Next up in News

2013 World Cup Rumour Mill with @Team Rumours