SRAM Eagle Transmission

[Shane4XC]

I’m coming up on needing a new cassette. Is the legacy AXS eagle derailleur compatible with the transmission cassette and chain? I’m curious about the improvements claimed by SRAM, but would rather not replace all my AXS bits.

Basically I’m willing to replace cassette, chain, and chain ring to SRAM t type if it’s compatible… but if I need to change the derailleur I wouldn’t consider it worth it.

[EB]

Originally Posted by Shane4XC

I’m coming up on needing a new cassette. Is the legacy AXS eagle derailleur compatible with the transmission cassette and chain? I’m curious about the improvements claimed by SRAM, but would rather not replace all my AXS bits.

Basically I’m willing to replace cassette, chain, and chain ring to SRAM t type if it’s compatible… but if I need to change the derailleur I wouldn’t consider it worth it.

The Transmission cassette cogs move outboard by 3mm compared to previous gen Eagle cassettes. In a full transmission setup, the chainline also moves out from 52 to 55mm.

I have no idea if the previous gen AXS Eagle derailleur will work with that cassette. You could try playing with the limit screws and the micro-adjust to see if you can get it to line up. The flat top chain is also required - I am pretty sure the previous gen derailleurs work with that.

[Shane4XC]

Originally Posted by EB

The Transmission cassette cogs move outboard by 3mm compared to previous gen Eagle cassettes. In a full transmission setup, the chainline also moves out from 52 to 55mm.

I have no idea if the previous gen AXS Eagle derailleur will work with that cassette. You could try playing with the limit screws and the micro-adjust to see if you can get it to line up. The flat top chain is also required - I am pretty sure the previous gen derailleurs work with that.

Hmm. I wonder if I could put a spacer in front of the derailleur to help with that.

Seems like some pretty significant changes though

[Dave]

Try the SRAM owners page on Facebook.

[tootall]

The transmission cassette has ramps that allow shifts at specific locations on the cassette, and the derailleur is timed to the cassette to only move at the right time to hit those ramps. A non transmission derailleur moves whenever you tell it to, but the chain wouldn’t be able to shift until it got to the ramp. I think the time between would cause some issues in the sense of heavy rubbing and noise. If the chain works with the AXS derailleur and the spacing between cogs is the same you could give it a try, but that’s a heavy investment not knowing if it’s gonna work!

[Shane4XC]

Originally Posted by tootall

The transmission cassette has ramps that allow shifts at specific locations on the cassette, and the derailleur is timed to the cassette to only move at the right time to hit those ramps. A non transmission derailleur moves whenever you tell it to, but the chain wouldn’t be able to shift until it got to the ramp. I think the time between would cause some issues in the sense of heavy rubbing and noise. If the chain works with the AXS derailleur and the spacing between cogs is the same you could give it a try, but that’s a heavy investment not knowing if it’s gonna work!

Thank you for this! Will stick to the standard I think… unless a cheap GX eagle t type shows up.

[capt_velo]

Originally Posted by Shane4XC

Thank you for this! Will stick to the standard I think… unless a cheap GX eagle t type shows up.

https://www.sram.com/en/sram/mountai...e-transmission

[coreydoesntknow]

Originally Posted by Shane4XC

Thank you for this! Will stick to the standard I think… unless a cheap GX eagle t type shows up.

How cheap is cheap?

[tootall]

Originally Posted by Shane4XC

Thank you for this! Will stick to the standard I think… unless a cheap GX eagle t type shows up.

There's a cool explanation here on the synchronized shifting, and how it keeps the chain engaged during the shift for continuous power transfer (which I didn't know before).

https://www.sram.com/en/sram/mountai...e-transmission

[benb]

Originally Posted by Shane4XC

Thank you for this! Will stick to the standard I think… unless a cheap GX eagle t type shows up.

Doesn't GX use a different cassette/hub anyway?

This stuff is super confusing. My MTB has the lower end Eagle with the different hub.. makes it super confusing to figure out what I could change it too if/when I kill the original derailleur or cassette.

It is fine though, there is absolutely no reason to upgrade it till it breaks/wears out.

[benb]

Does this synchronized shift thing slow down shifting even more?

The huge cassette spacing + weird latency with electric shifting kind of seems like a step backwards sometimes. Slowing it down even more seems like an odd idea.

I don't think it really matters and if it lets you keep applying power I guess it's fine but it definitely seems odd.

I think I time my shifts anyway so I don't notice, but the electronic stuff I've ridden has not really impressed me on speed. Maybe I'd adjust to hit the button earlier if I actually bought one of the groups.

I think it is more cassette than anything.. 1x and a pie plate cassette just feels slow.

[rice rocket]

Originally Posted by benb

Does this synchronized shift thing slow down shifting even more?

The huge cassette spacing + weird latency with electric shifting kind of seems like a step backwards sometimes. Slowing it down even more seems like an odd idea.

I don't think it really matters and if it lets you keep applying power I guess it's fine but it definitely seems odd.

I think I time my shifts anyway so I don't notice, but the electronic stuff I've ridden has not really impressed me on speed. Maybe I'd adjust to hit the button earlier if I actually bought one of the groups.

I think it is more cassette than anything.. 1x and a pie plate cassette just feels slow.

That's common complaint on the Transmission reviews.

Interesting design choice for a groupset where terrain can change rapidly from down to up, or vice versa.

[tootall]

Originally Posted by benb

Does this synchronized shift thing slow down shifting even more?

The huge cassette spacing + weird latency with electric shifting kind of seems like a step backwards sometimes. Slowing it down even more seems like an odd idea.

I don't think it really matters and if it lets you keep applying power I guess it's fine but it definitely seems odd.

I think I time my shifts anyway so I don't notice, but the electronic stuff I've ridden has not really impressed me on speed. Maybe I'd adjust to hit the button earlier if I actually bought one of the groups.

I think it is more cassette than anything.. 1x and a pie plate cassette just feels slow.

It does slow shifting because the cassette has to come around to the right spot before it shifts. I haven't ridden it, but the people I know who have it say it's noticeable.

I think the regular AXS is plenty quick to shift, and seems quicker than mechanical to me, primarily due to the lower/quicker effort at the lever and I feel like the derailleur move is instant after that. I just put AXS on my MTB after first using it on my road bike and I've been loving it. The biggest problem I've had is trying to remember which paddle to push for up/down shifts after so many years of mechanical shifter muscle memory.

[benb]

I had rental MTB last year with XX-something or other electronic, that is my only real experience with the SRAM stuff. I had the same issue at first with getting confused by muscle memory with the paddle versus mechanical shifters but I got used to it really quick so no big deal. My bike had basically zero issues, but my wife had another one with the same groupset and hers did have a little bit of issues, though if I owned the group I would have learned how to fix it, it was very easy once the shop told me how to do it.

It just seems odd so much of the potential for faster shifting seems to have gotten traded off with the current giant cassettes. A lot of what I notice is mechanical starts shifting with the depression of travel on the lever whereas electronic kind of triggers once you get to the end of the throw of the paddle. That is just what throws me off and would require adjustment.

In terms of getting rid of cables on the MTB my inclination would be to go for it, probably at the lowest level that works. My MTB seems like the worst of both worlds right now with a mix of external and internal hoses/cables so getting rid of some of the clutter would work. The worst part is that the hydraulic hoses were cut way too long at the factory and I need to redo them though. If I went to wireless electronic and then correctly sized the hydraulic lines it would clean it up a lot.

In any case my current mechanical Eagle sometimes feels yucky downshifting under power on steep climbs but it always gets the job done. Getting more fit will always make it feel better too, cause you're in smaller cogs when you have to shift, and the system shifts better the higher you get in the gearing.

[tootall]

Originally Posted by rice rocket

Interesting design choice for a groupset where terrain can change rapidly from down to up, or vice versa.

I feel like the bigger target for Transmission is ebikes, where I would assume quick shifts matter a little less?