Support road.cc

Like this site? Help us to make it better.

TECH NEWS

SRAM goes 12-speed

Will new mountain bike setup eventually convert to the road?

SRAM has introduced a 12-speed drivetrain called Eagle to the world of mountain biking, with no front derailleur; is a similar setup likely for the road market in the not too distant future?

SRAM has been beating the drum for 1x (pronounced ‘one by’) systems – with just a single chainring at the front and a wide-ranging cassette at the rear – for a long time now. Single chainrings have become popular in mountain biking, and SRAM has more recently introduced 1x versions of its Force, Rival and Apex road groupsets. That’s all of its road groups apart from top level Red.

The new Eagle mountain bike groupset is different in that it’s 12-speed as opposed to 11-speed, and it is only available as 1x. There’s no such thing as an Eagle front derailleur. 

SRAM Eagle - 2.jpg

Isn’t that limiting? Well, Eagle offers a 500% gear range (the difference between the bottom gear and the top gear), which is 20% more than SRAM’s existing 1x groupsets. That’s a larger range than a typical double chainring road setup.

The 12-speed Eagle cassette goes all the way from 10-tooth right up to – wait for it – 50-tooth. Bear in mind that 50-tooth is the size of the outer chainring of a compact chainset! You can use chainrings from 30-tooth up to 38-tooth with Eagle.

What’s the point in a 1x setup? SRAM says that it is simpler because there’s no front mech or front shifter, there’s no chance of the chain rubbing on a non-existent front mech, and it’s quieter on rough surfaces. 

SRAM says that the interface between the chain and chainring is better because their chainrings have tall, square teeth edges that engage the chain earlier, and the traditional sharp and narrow tooth profile helps manage a deflected chain.

Check out our SRAM 1X First Ride from last year. 

SRAM also says, “Eagle has a significant weight advantage over other drivetrains—XX1 Eagle weighs up to 300g less than 2x drivetrains with a similar gear range.”

We won’t go into too much depth on Eagle here because we’re a road website, after all. We’re more interested in whether this suggests that 12-speed is likely to make it on to the road and whether it heralds the death of the front mech. 

SRAM Eagle - 4.jpg

Assuming it was possible, would you ever need a 50-tooth sprocket on the road? Probably not, although if you wanted to run a 52-tooth single chainring in order to get larger gears, having a 50-tooth sprocket (on a bike with a 700 x 25 wheel/tyre) would give you a smallest gear size of 27.4in. That’s only a fraction smaller than you get using the 34-tooth inner chainring of a compact 2x chainset with a 32-tooth sprocket (that gives you a 28in gear).

In other words, the extra range offered by adding a 50-tooth sprocket could conceivably be useful if you wanted both very small and very large gears.

Would the change from 11-speed to 12-speed benefit you? Probably not much, although assuming you didn’t want a 50-tooth sprocket, SRAM could reduce the size of the largest jumps in sprocket size on its current cassettes.

Using SRAM’s 12-speed system requires a mountain bike-style XD Driver body (you already need one of these to use an existing SRAM 10-42-tooth 11-speed cassette) rather than a standard freehub body, but the overall width of the cassette isn’t very different from an 11-speed one because of a narrower chain width and a smaller gap between the sprockets. If your wheels currently take an 10-42 cassette, they’ll take a 10-50 cassette.

We’re guessing that getting a 12-speed cassette to fit to an existing 11-speed freehub body would require some work from SRAM but that it would be possible. 

SRAM Eagle - 3.jpg

Obviously, SRAM would have to alter the rear derailleur of its existing road systems if it wanted to offer the 500% gear range of Eagle (for Eagle, it has increased the length of the cage and the size of the lower jockey wheel compared with existing models, and updated the Roller Bearing Clutch) but, again, that doesn’t seem beyond the realms of possibility.

We have absolutely no inside knowledge that SRAM is working on such a system but we wouldn’t be at all surprised to see 12-speed coming to a road bike near you shortly.

Let us know your thoughts.

Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

Add new comment

18 comments

Avatar
Tjaardbreeuwer | 7 years ago
0 likes

"Due to the huge sprocket & triangulation of the spokes, the 12th gear should be able to overhang the end of the existing 11spd cassette body."

It actually does overhang. SRAM must have had the same idea as you.

Avatar
Jay88 | 8 years ago
0 likes

Giving up 18 gear ratios (possibly 16 if we ignore large large, low low combo) because it's simpler, lighter and less noise? 

Avatar
fixit | 8 years ago
0 likes

Why anyone in the british countryside require a cassete with more than 32t at the rear and 38t single at the front on a mountain bike? and for road, 42t front and 11-28 rear is more than enough. do you agree?

Avatar
bikebot replied to fixit | 8 years ago
3 likes

tsarouxaz wrote:

Why anyone in the british countryside require a cassete with more than 32t at the rear and 38t single at the front on a mountain bike? and for road, 42t front and 11-28 rear is more than enough. do you agree?

No. Because your definition of "anyone" appears to be rather narrow.

Avatar
Morat replied to fixit | 8 years ago
2 likes

tsarouxaz wrote:

Why anyone in the british countryside require a cassete with more than 32t at the rear and 38t single at the front on a mountain bike? and for road, 42t front and 11-28 rear is more than enough. do you agree?

 

No, I don't. Maybe you're an ace climber or maybe you live somewhere with flatter hills than North Yorkshire but there's no way I'd get up some of my local hills with 42/28.

Avatar
700c replied to fixit | 8 years ago
2 likes
tsarouxaz wrote:

Why anyone in the british countryside require a cassete with more than 32t at the rear and 38t single at the front on a mountain bike? and for road, 42t front and 11-28 rear is more than enough. do you agree?

At the risk of feeding the troll.. no I don't agree. I assume you don't like to climb up steep hills for any length of time and/or you don't value your knees?

Given the proliferation of compact cranks in the UK and the short, sharp climbs we have here, you would appear to be in a minority and relishing your position as some kind of macho follower of 'the rules' or similar BS.

Avatar
ch | 8 years ago
0 likes

If the single crank could be moved laterally in concert with shifting, it would eliminate cross chaining

Avatar
Mungecrundle | 8 years ago
2 likes

If you could double up the function of the 50 tooth rear as a disc brake then you could really annoy some people.

Avatar
joemmo replied to Mungecrundle | 8 years ago
1 like
Mungecrundle wrote:

If you could double up the function of the 50 tooth rear as a disc brake then you could really annoy some people.

That sounds like a kickstarter project waiting to happen.

Avatar
antigee | 8 years ago
1 like

 

 

"I love my bike"        "It would also reduce the entry cost of an etap system."

this is where I'd like to go - one review of etap had individual component costs and the front mech cost was by far the most expensive component - using a microswitch and a sender unit on the bars makes MTB or flat bar road bike set ups attractive versus the engineering of etap into a traditional road lever

 

 

Avatar
mrmo | 8 years ago
0 likes

do have to wonder at what point it makes more sense to ditch the cassette and deraileur and seriously look at gear boxes, either  at bottom bracket or rear hub. 

Avatar
bikebot replied to mrmo | 8 years ago
0 likes

mrmo wrote:

do have to wonder at what point it makes more sense to ditch the cassette and deraileur and seriously look at gear boxes, either  at bottom bracket or rear hub. 

Well we have those, but a hub gear will never beat a derailleur on weight. A nexus-11 is 1.7kg, the Rohloff a little more.  

I would like to see somene make a pure electric shifting gear hub, using solenoids rather than mechnical links could lead to a much simpler and lighter unit.

Avatar
bendertherobot | 8 years ago
0 likes

I'm very fond of my Cannondale SI Hollowgram 52/36 with 11-28. Good range, very good at speed. For really quick riding I like it very much.

But I also love both my 1x setups. Both are 12-36 and 42 and 44t respectively. Great for all sorts of things. I'd love to have a gravel grinder with big balloony tyres and an even bigger rear cassette. Not sure I'd need 50t but if it's 12 speed it's nice to have. 

It's going to be a weird feeling having a rear cog that's as big as a road compact big ring mind.

Avatar
stephen connor | 8 years ago
0 likes

I'm currently running a 1 x 10 on my winter/second bike Giant Defy 3.5. Its a complete shimano mashup 52 Chainring (with bash guard and jump stop chain catcher), HG62 (Deore) 11-32 cassette, Tiagra 4601 GS rear mech and 105 5600 Sti levers. I wanted to try the setup before droping several hundred euro on the full kit. Its a great set up with a couple of caveats

  1. A clutch derailleur would be great as chain slack can induce the very odd chain drop to the outside when dumping several cogs down in quicj succession hence a chain guide / bash gaurd is essential.
  2. The ratio steps as you reach the upper end of the cassette (25-28-32) are slightly greater than ideal.

Chain slack / chain drop would be sorted by the narrow wide chainring and clutch derailleur. The large jump in cassette ratio would also be handled with the 12 speed cassette. The only issue with this is the smaller bottom gear of 34 or 36 may cause problem with the cassette fouling the spokes.

I've been using the setup for a couple months now and i believe with 11-34 or maybe 11-36 cassette I would be more than happy to use the 1 x "one by" option on a permanent basis for all my bikes. I have used my current setup some short steep climbs with section of over 20% for a couple of hundred metres.

Avatar
I love my bike | 8 years ago
2 likes

Due to the huge sprocket & triangulation of the spokes, the 12th gear should be able to overhang the end of the existing 11spd cassette body.

Seems perfect for round-the-world cyclotourists, beginner sportive riders & very cheap bikes. It would also reduce the entry cost of an etap system.

Existing 22 speed systems have duplicate ratios & limitations due to cross-chaining, so it might not have much larger jumps between ratios, or be like those of an 18spd?

Like a brake disc, it's not very aero though  1

Avatar
part_robot replied to I love my bike | 8 years ago
2 likes

I love my bike wrote:

Like a brake disc, it's not very aero though  1

I wouldn't be surprised if it's actually more aero. You're only increasing the frontal area by a tiny amount relatively speaking and - furthermore - in a region so turbulent as to almost not matter. Meanwhile, you're making quite a big difference on the frontal area in the smoother region by removing a chainring and a derailleur. Furthermore, the design opens up new geometries that could smooth the flow around the seat tube and bottom bracket area.

Avatar
Initialised | 8 years ago
0 likes

50 upfront and 10 - 50 out back with a clutched derailleur and customisable, gradient sensitive semi auto shifting. All you have to do in spin and steer. Purists will hate it!

Avatar
pedalpowerDC | 8 years ago
3 likes

Get ready for $400 cassettes

Latest Comments