SRAM's new 2023 Drivetrain allows full power shifts

p3eps

E*POWAH Elite World Champion
Subscriber
Dec 14, 2019
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Scotland
I got an email about this an hour ago and was reading about it.

My question / fear is that the derailleur hanger is a £10 part that bends / snaps when you catch the derailleur on a rock / log etc. You can carry a spare in your pack and potentially get back up and running at minimum cost.

What happens when you clatter this off something? Does the whole derailleur need replaced?
 

Zimmerframe

MUPPET
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Jun 12, 2019
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Brittany, France
It does look impressively solid and with the axle going through both sides, well supported.

Wonder how it handles the dreaded jumping stick feeding into the pulleys when you're pedalling full tilt though ...

1679413567046.png
 

Dave_B

E*POWAH Elite World Champion
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Aug 29, 2020
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Newquay
I wonder how much a GX version will be for just the mech, shifter and chain.
(Assuming any 12sp chain ring will work with it)
 

Rob Rides EMTB

Administrator
Staff member
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Jan 14, 2018
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Surrey, UK
Here's some FAQ:

Can I upgrade my mountain bike to Eagle Transmission?
Any frame that fulfills the “UDH Specification” featuring a hanger-less interface can be upgraded. Complete specification information can be found at universalderailleurhanger.com

How will I know if my bike is UDH (Universal Derailleur Hanger) compatible?
SRAM UDH Bike finder lists all UDH bikes that are compatible with Eagle Transmission. bikefinder.sram.com

Do I need the AXS app to set up my Eagle Transmission every time?
No, you can install Eagle Transmissions quickly and easily without ever using the AXS App. If you need installation instructions, set-up key configurations, or the chain size for your bike, you can consult AXS Web, the installation manual for Eagle Transmission, as well as the installation videos.

Derailleur hangers break or bend to protect the rear derailleur. What happens if I crash with Eagle Transmission?
Bent hangers can cause several issues, from bad shifting to, with a severely bent hanger, the rear derailleur jamming into the wheels and can result in catastrophic damage. The Eagle Transmission rear derailleur is connected to the axle system and is designed to be extremely robust against side and frontal impacts so you can continue your ride after a crash.

What does the “Setup-Key” do?
The “Setup-Key” in the correct position for your bike paired with the correct “Setup- Cog” allows chain gap pre-adjustment without B-Screw in the repair stand (without sag) so the chain gap will be correct when the bike moves into the sag position while riding. No more phoning a friend for chain gap setup.

The Eagle Transmission derailleur cage looks bent, is this normal?
The “Inline Cage” is bent by design. It always points the chain towards the front chainring – in any gear, helping achieve the smooth and quiet operation of the transmission in all cogs.

How do I know, what “Setup-Key”-position is needed for my bike?
Please visit the SRAM AXS App or AXS Web Eagle Transmission Setup and search for your bike.

How do I know what size chain to use with Eagle Transmissions?
Chain length for Eagle Transmissions is determined by the chainstay length of the bike at full extension (not compressed), and the chainring size. Chain length can be found in the AXS app set-up guide, in the manual, or on the chain chart found here: Eagle Transmission Chain Length Chart

Do I have to re-adjust the system after I take the wheel out?
No, the adjustment position will be maintained when the axle is loosened and re-installed.

Do I have to re-adjust the system when I change the chainring size/ chainstay length?
Yes, these changes affect the chain length needs of the system and the position of the upper pulley, which is important for the best shifting performance. You need to check the correct chain length (with the app) and
adjust the chain accordingly. Next, re-do the set-up process to adjust the position of the upper pulley wheel to the new setup. The same is true for any other drivetrain system.

Are Flight Attendant and Eagle Transmission compatible?
Yes. Flight Attendant requires a pedal sensor to detect the rotation of the crank. Eagle Transmission can be equipped with SRAM AXS Eagle Transmission spider or spindle based Quarq power meters which function as the Flight Attendant pedal sensor, as well as a power meter.

Is there a mullet configuration for Eagle Transmission on road and gravel bikes? Yes, SRAM 1x AXS Road chainrings are compatible with T-Type chains. Therefore, Eagle Transmission can be used with a SRAM AXS road chainring and crank for a mullet configuration. The frame needs to be UDH compatible.

Why does Eagle Transmission use a 55mm chain line and what is the result?
Eagle Transmission features a SRAM MTB WIDE crank with 55mm chain line while using the Boost 148mm Over- Locknut Dimension hub standard. This is made possible by the frame adjustments implemented with UDH to allow for more clearance around suspension bearings, tires, and chain stays. Eagle Transmission cassettes move outboard by 2.5mm to optimize for this wider, 55mm chain line. For bikes with SuperBoost 157mm hubs,
a 55mm chain line crank can be used. For bikes with a 142mm hub spacing, a 52mm link crank must be used.

I hit my rear derailleur on a trailside object, and it rotated backwards. How do I reset it?
How do you know if it is reset? Check that the rear derailleur has rotated relative to the knurled ring by inspecting the hash marks on the inboard top side of the hanger-less interface, they should be aligned. If they are not, you can push the rear derailleur forward by hand until they align or loosen the axle and allow the rear derailleur to rotate forward under the spring force of the cage. Resetting the mount bolt is not required.

What is the correct torque for my axle when using Eagle Transmission?
Axle torque plays a role in how hard it is to rotate the Eagle Transmission rear derailleur rearwards with an impact, as well as how hard it is to reset it manually. Follow the axle torque recommendations specified by the bike or axle manufacturer.

Can I use the POD controller on previous Eagle AXS drivetrains?
Yes, the POD electronic controllers can be used with Eagle Transmission, as can any other two button SRAM AXS electronic controller. Eagle Transmission is also compatible with eTap AXS Wireless Blips.

Can I mix Eagle Transmission parts with Eagle drivetrain parts?
No. Eagle Transmission does not work with any previous Eagle components. However, Eagle Transmission T-Type chainrings are backwards compatible with Eagle chains, so can be used on the current Eagle drivetrains. Non-T- Type Eagle chainrings will not work with Eagle Transmission chains, however.


Why are Eagle Transmission cranks and chainrings 8-bolt pattern?
The 8-bolt pattern is required for use with Quarq AXS power meters. The 8-bolt pattern on Eagle Transmission allows all cranksets to be upgraded to a spider based power meter if desired.

Shifting Eagle Transmission in the repair stand seems rough compared to when riding. What is wrong?

Our Transmissions are designed to be ridden, and riding happens at SAG for full suspension bikes. The radically simplified set-up of Eagle Transmission accounts for the SAG position to properly set chain gap. When a full suspension bike is fully extended, as in a bike stand, the chain gap is smaller than optimal and may result in rough shifting. Ride your bike at SAG!

I hit my rear derailleur and scratched up the outside of it. Can I make it look fresh again?
In most cases, yes. Eagle Transmission rear derailleurs are designed to have replaceable points of frequent contact: the skid plate (if equipped), the outer parallelogram link, and the cage and damper assembly if needed. Go to your retailer to find SRAM Eagle Transmission replacement parts.

Do the T-Type chainring bash guards fit on any Eagle chainring?
No, the Eagle Transmission bash guard only fits on Eagle Transmission chainrings. If your Eagle Transmission Chainring
did not come with a Bash Guard as specified by the bike manufacturer or as an aftermarket kit, go to your retailer
to find SRAM Eagle Transmission Bash Guard parts. Eagle Transmission XX SL chainrings and spider based power meters are NOT compatible with Bash Guards.

When I shift Eagle Transmission repeatedly, the rear derailleur takes time to catch up and shift. What is going on?
With Eagle Transmission, you can shift under full load. Cassette shift mapping utilizes rigorously designed shift ramps on the cassette to ensure both up and downshifts happen at precisely the right time, for the smoothest shifting. Aligning the chain with these T-Type shift ramps delivers the best shifts. Do not wait for the shift, just keep pedalling under power!

Can I run Eagle Transmission on my E-MTB?
Yes, absolutely. Eagle Transmission was designed to shift under load, for E-MTB applications. Choose Eagle Transmission for the best performance on E-MTBs. It is not recommended to use Eagle Transmission XS-1299 T-Type Cassettes or XX SL Chains on E-MTBs. These parts are designed for the lightest weight applications and will wear out prematurely on E-MTB applications.

The Eagle Transmission chain looks like a 12-speed road chain, is it cross compatible with road 12- speed drivetrains?
No, the Eagle Transmission shares a silhouette of the SRAM AXS Road chains but has a unique design to achieve its performance.

The Eagle Transmission drivetrain doesn’t have High, Low, and B-gap screws to set up the derailleur. How is that possible?
Eagle Transmission is like no other drivetrain and takes advantage of a radically simplified set-up process due to the rear
derailleur direct-mounting to the frame, removing the variation in RD position from bike to bike. Follow the faster than
ever before installation method of Eagle Transmission for best-in-class performance.

Eagle AXS Transmission rear derailleur battery life seems shorter than with previous AXS rear derailleurs. Why is there a difference?
Eagle Transmission rear derailleurs have a higher cage damper force than previous Eagle AXS rear derailleurs and therefore require more force and energy to shift the Transmission into inboard gears. Also, the improved shift quality naturally makes riders shift more frequently per ride.

What is the Q-factor of the Pedal Assist Cranks?
All Pedal Assist E-MTB Cranks are designed to be Q174, note the output-Q is always depending on the spindle length of the motor, which varies from every supplier and even within supplier e.g., BOSCH Gen 4 vs. Gen 6. That is why we have different offsets in the cranks. The BOSCH offset is higher (shorter spindle) the crank arm is straighter and has less offset to work with the longer spindle. It would be more accurate to call out the crank offset, but for the rider the BOSCH vs. BROSE has more value. When paired with the motor platform called out in the part description, our E-MTB Pedal Assist Cranks are roughly 180mm, with variation due to the motor spindle.

What Q-factor is the ISIS Pedal Assist Crank based on?
Our ISIS variant (neither calling out BROSE or BOSCH) is based on the BOSCH offset and fits most other motors that feature an ISIS interface.

Can the ISIS E-MTB Pedal Assist Crank be used with the 3-bolt cap?
No, the ISIS cranks are not designed to be configured with the cap that visually covers the space between the crank and spider/chainring and are therefore not recommended to be used with BOSCH motors, to avoid the visual gap.

Does SRAM manufacture E-MTB spiders for my bike?
SRAM MTB does not manufacture spiders for E-MTBs, except for Specialized’s Mahle motor platforms. SRAM Road offers a BOSCH and Fazua spider.

Is there an Eagle Transmission crank with a narrow Q-factor?
There are narrower Q-factor crank available in the XX SL crank offering, while maintaining a 55mm chain line for Eagle Transmission. These are 168mm Q-factor and use the DUB SL spindle.
1679417546175.png
 

yorkshire89

E*POWAH Master
Sep 30, 2020
468
661
North Yorkshire
That's neat .. but if the stick gets pulled along the bottom chain line and then gets gobbled by the bottom jockey wheel, the chain force will still try to tear the mech off ??

True, there's only so much you can do when you still have a mech in this position. The mech will rotate backwards if it his impacted from the front which should help to an extent.

As good as it is I'd still prefer a gearbox...
 

B1rdie

E*POWAH Elite World Champion
Subscriber
Feb 14, 2019
845
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Brazil
I have a question!
Does it shift with the pedals idle like the new shimano di2?
 

iadmtb

Member
Jan 23, 2023
53
32
Thousand Oaks, CA
So in order for Specialized Turbo Levo users being able to use this drivetrain, we'd have to use a SRAM crank and chainring, but they don't have a 160mm crank, correct? Shortest crank they offer is 165mm? Do they offer a chainring that we can use on existing stock turbo levo cranks?
 

head

Active member
Jul 2, 2020
120
115
Slovakia
So in order for Specialized Turbo Levo users being able to use this drivetrain, we'd have to use a SRAM crank and chainring, but they don't have a 160mm crank, correct?


"Available with 160mm crankarm and 36T chainring"
 

beanzz

Member
Feb 7, 2023
331
275
United Kingdom
I got an email about this an hour ago and was reading about it.

My question / fear is that the derailleur hanger is a £10 part that bends / snaps when you catch the derailleur on a rock / log etc. You can carry a spare in your pack and potentially get back up and running at minimum cost.

What happens when you clatter this off something? Does the whole derailleur need replaced?
I mean just watch some of the videos on it, eg the pinkbike one has him full on jumping on it while it's attached
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,892
20,583
Brittany, France
Eagle AXS Transmission rear derailleur battery life seems shorter than with previous AXS rear derailleurs. Why is there a difference?
Eagle Transmission rear derailleurs have a higher cage damper force than previous Eagle AXS rear derailleurs and therefore require more force and energy to shift the Transmission into inboard gears. Also, the improved shift quality naturally makes riders shift more frequently per ride.
@Rob Rides EMTB ... Well spotted whilst you were testing it !
 

Streddaz

Active member
Jul 7, 2022
267
382
Tasmania
I got an email about this an hour ago and was reading about it.

My question / fear is that the derailleur hanger is a £10 part that bends / snaps when you catch the derailleur on a rock / log etc. You can carry a spare in your pack and potentially get back up and running at minimum cost.

What happens when you clatter this off something? Does the whole derailleur need replaced?
It's actually a myth that the hanger is designed to protect your derailleur. It was initially designed to protect your frame, so if something catches your derailleur, yes it would wreck the derailleur, but the hanger would bend before your frame. Once upon a time the hanger was a part of your frame. When aluminium bikes started appearing, straightening an aluminium section in not a good ideas due to the way aluminium fatigues, so a bolt on failure point was created.
Just look at most hangers, they are way thicker than the parts on a derailleur, the derailleur is definitely going to break first.
Will the new direct mount damage your frame? Possibly not but time will tell. The derailleur cage (which is the part that usually gets caught up on objects) will still bend before anything else.
 
Last edited:

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