It’s been one of worst-kept secrets in the world of mountain biking, but SRAM has finally announced its all-new 12-speed single ring mountain bike drivetrains, called XX1 Eagle and X01 Eagle. BikeRadar was there to ride the new groupset and get the full lowdown, so read on for all the specs and tech details and the reasons why we think this news is the beginning of the end for the front derailleur.
If you don’t care about the tech and just want to know how it rides, you can check out our initial impressions of SRAM 12 speed Eagle in our first ride review.
1. It’s got a gear range comparable to many double ring setups
The most obvious change over the outgoing XX1 and X01 groups is that the twelfth sprocket on the cassette is a rather humongous 50t item. That gives you an impressive 500% gear range with a single ring up front. For comparison, Shimano’s new 11-46t cassette only has a 418% range with a single ring setup and a 36/26t double with 11-40t cassette gives a 504% range.
Okay, you could run a Shimano double with the new wider range cassette to get a range up to a staggering 592%, but that doesn’t seem much use unless you regularly pedal up near vertical slopes before cranking it downhill on steep and smooth trails; hardly a common mountain bike riding situation. Front rings are available from 30T-38T, so there’s plenty of choice to tune the gearing to your riding needs too.
Another smart thing about Eagle is that it uses the same steps between gears as SRAM’s existing single ring drivetrains, while the jump from the 42t cog to the new 50t is only 19%. The overall width of the new cassette isn’t far off an 11spd item either, thanks to a slightly narrower chain width and gap between cogs. The 10t cog sits in the same place, while the 50t is slightly more inboard than the largest 42t cog of an 11spd SRAM cassette thanks to a dished profile.
SRAM has worked with a large number of wheel manufacturers to make sure it’ll work with pretty much every wheel on the market today too – if it you can fit an XX1 cassette on there, you can fit an XX1 Eagle item on there. The Eagle cassette is made in the same way as current XX1 and X01 too, with the first 11 cogs being machined from a single piece of high strength steel, with the 50t cog being made from aluminium and riveted to the steel block. The different chain width and spacing does mean that there’s almost no backwards compatibility with SRAM’s 11spd groups though – chainring is the only part that will work with an 11spd chain.
2. There’s hardly any weight or price penalty over existing SRAM 11spd drivetrains – and it’s much lighter than any double
3. SRAM says it’s going to be much longer lasting
4. It’s going to revolutionise bike design
5. It’s eventually going to trickle down to affordable bikes
You can read more at BikeRadar.com