SRAM XO1 Eagle 12speed | First Ride

June 20th, 2016

By Andrew Dodd in Tech

SRAM XO1 Eagle 12speed – the full low down 

Back in March, SRAM unveiled the staggering new 12 speed transmission, which features the much talked about 10-50 range cassette.

Last week I spent a day with SRAM in the Forest of Dean, kitting out my Mondraker Dune with a full SRAM XO1 Eagle transmission and finding a bit more about the new technology…

The Details

As always, SRAM put on a slick presentation and sent along marketing man Alex Rafferty, to make sure we set our system up correctly and had all the facts.

The biggest question people have been asking about the new SRAM XO1 Eagle is how much heavier the huge 12speed cassette is than the 11speed options. The concern is that having a heavy cassette adds weight to the unsprung mass, which could affect suspension performance.

The 11 speed SRAM XO1 cassette weighs in at 268grams, whereas the new SRAM XO1 Eagle 12 speed version weighs in at 355grams – just 87grams more. Which is impressive considering the sheer size of the 50tooth sprocket!

The design of the cassette is very similar to the 11speed system, and mounts using the same XD driver body. With a 10-50 gearing spread (10, 12, 14, 16, 18, 21, 24, 28, 32, 36, 42, 50) you can climb virtually anything, and run a slightly larger chainring too giving a bigger high end gear.

SRAM XO1 Eagle

SRAM’s Alex Rafferty was on hand to help set up our Eagle 12 speed transmission, and explain how vital set up is for clean shifting.

The same SRAM layout is present throughout the new Eagle XO1 drivetrain – but things have been redesigned specifically to cater for the enormous gear range now on offer, and set up takes a little more care.

The rear derailleur still uses the X-Horizon design, and still has the Cage Lock – though it’s tucked further back. Most noticeably on the rear mech is the huge new 14tooth lower jockey wheel. The clutch is now a type 3 design, and is much smoother in use.

SRAM XO1 Eagle

I installed the SRAM XO1 Eagle transmission to my long term bike – the Mondraker Dune RR. Although the 50tooth sprocket is massive, it blends in and isn’t too hard on the eye.

First Flight With Eagle

Changing gear with SRAM XO1 Eagle is a nice experience – the same direct, positive click is there – though the shifter now feels more responsive. There’s less throw and a faster downshift too.

Although SRAM say the new Eagle carbon cranks are their stiffest yet – it’s hard to tell until we spend a bit of time on some rougher trails.

The X-Sync 2 chainring and Eagle 12 speed chain combination are noticeably quieter than some of our older 11 speed set ups though – we expected more noise, not less. Which is damned impressive.

SRAM XO1 Eagle

Although the SRAM XO1 Eagle chain has to contort through a huge range of gearing, it is incredibly quiet and shifts near enough silently. Unlike previous chains, the Eagle chain has no square edges on any of the plates – this makes a massive difference to how smooth it runs.


To cater for the huge gearing range, the lower jockey wheel is much bigger than before and has 14 teeth. Combined with the smoother action of the Type 3 clutch system, the new SRAM XO1 Eagle rear mech works excellently.

Smooth, quiet upshifts and lightening fast downshifts with that punchy feel that SRAM are known for.


SRAM XO1 Eagle

The 10-50 cassette really is a work of art – the construction is stunning and you can’t help but be amazed just looking at the thing. The slight weight penalty might play on the minds of some, but in reality it’s not noticeable when you’re out on the trail.


SRAM XO1 Eagle

The 500% gear range of the SRAM XO1 Eagle cassette might sound ridiculous – but there are always scenarios when you need that ‘get me home’ gear. Friends who compete in events like the Trans Provence have mentioned how it would be great to have that extra gear, and those who put the miles in will appreciate it too. Although we’ve not had to rely on the insane 50tooth to get us out of trouble yet, we’re sure it will come in handy soon!


Here are the full details of the SRAM XO1 Eagle drivetrain:

  1. XO1 Eagle carbon crank with X-Sync 2 chain ring  $390 | €426 | £328
  2. XO1 Eagle rear derailleur, Type 3 Roller Bearing Clutch $220 | €240 | £185
  3. XO1 Eagle trigger shifter $127 | €145 | £112
  4. XO1 Eagle XG-1295 12-50 Cassette. 355grams, 10-50, $360 | €392 | £302
  5. XO1 Eagle chain, $60-85 | €66-92 | £50-71
  6. Complete groupset price – $1,193 | €1,306 | £1,005

We Say

Although initially sceptical about how heavy the cassette would be; how smooth shifting would be and if we actually needed the enormous 10-50 gear range of the SRAM XO1 Eagle transmission – we can’t really find any faults at this stage. 

The shifting is very smooth – especially the down shift – and the chain seems to be the quietest yet.  It’s hard not to like this wild set-up from the off!

However, the jury is still out on whether this amount of gearing is actually needed for many riders – but we like that the option is there. Alpine riders will certainly benefit from it, as will those wanting to run bigger gearing up front without losing out on low range gearing.

We’ll be leaving the 12 speed transmission on until it wears out – we will keep you updated with any rear mech waggle or troublesome shifting that might occur in the coming months.

What do you think of the SRAM Eagle 12 speed transmission?

Is 12 speed too much, or what you’ve been waiting for? 
Let us know in the comments below…




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