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Two SRAM Mechanical T-Type Transmission Derailleurs Soon, Both NX & SX? Patent Patrol

SRAM Mechanical T-Type NX Transmission derailleurs
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Long before UDH became a well-known acronym and widely-adopted standard, our first Patent Patrol sneak peek at SRAM’s direct mount T-type derailleurs illustrated a clearly mechanical Transmission. Now six years later, patent offices just published an updated SRAM mechanical T-type application. And at the same time, bike dealer sites have been trickling out leaked specs for not one, but two different SRAM mechanical Transmissions.

SRAM Mechanical T-Type Transmission derailleurs, ide view
(SRAM patent drawings/Bikerumor illustrations)

It looks like we’re on the verge of seeing 2 all-new more affordable mechanical shift SRAM Transmissions. Are mechanical SRAM NX Eagle Transmission and SRAM SX Eagle Transmissions coming very soon?

SRAM Mechanical T-Type Transmission derailleurs very soon!

SRAM mechanical transmissions are coming soon with both NX and SX Transmission derailleurs, Eagle 70
(online spec screenshot)

The secret of the new SRAM Mechanical T-Type Transmission broke first with references to a “SRAM Eagle 70 Transmission”. But how did we get here?

sram transmission direct mount rear derailleur installation closeup
(Photo/Tyler Benedict)

Sure, we saw a direct-mount mechanical SRM derailleur all the way back in 2018 with that first patent filing. But then, there was no more concrete mention of mechanical shifting for six years, while SRAM pushed their UDH standard out onto tons of off-road bikes and used the T-type mount as a sales driver for their top wireless AXS electronic drivetrains – first for XX SL, XX & X01, then more attainable GX AXS before going gravel with Red XPLR AXS. And, most affordably but still electronic for OEM-only as S1000 AXS, just last summer.

So what is Eagle 70 Transmission?

SRAM mechanical transmissions are coming soon with both NX and SX Transmission derailleurs, just NX
(online spec screenshot)

We read rumors of ’70 Transmission’ as early as September last year, but didn’t really have much confirmation as to what that meant. And I hadn’t seen it written in any publicly accessible space until this past month. Digging deeper into upcoming bike specs online though, I uncovered a second – seemingly compatible – reference to “Sram Eagle 90 Transmission”.

That’s when it really started to click.

SRAM mechanical transmissions are coming soon with both NX and SX Transmission derailleurs, Eagle 90
(online spec screenshot)

Both 70- & 90-level specs include a reference to a “Single-Click” shifter. And there’s importantly no cross reference to any AXS (wireless), all but confirming that this is mechanical shifting, not electronic. Some of the mixed-level specs refer to an NX derailleur – traditionally just below GX in the SRAM hierarchy. And some say just Eagle 70, which could be the OEM-only SX level?

Interestingly, it does seem that 70 Transmission is backward compatible with the current AXS Transmission. And some of you may already have the new – probably lower-priced – components on your (e)bikes. Specifically, it looks like some MY25 Bulls eMTBs with SRAM GX AXS electronic drivetrains may have already been spec’d with the new ‘Eagle 70 Transmission’ cassettes, likely as a cost savings tool.

What’s new in this latest SRAM Mechanical Transmission patent?

SRAM Mechanical T-Type Transmission derailleurs, direct mount detail

The language of patent applications is always quite dense, and often hard to parse. But one key difference since we first saw a mechanical derailleur in SRAM’s direct mount T-type Transmission filings, is that this new US20240246634A1 application (and to be fair, a few others since) is now actually for the derailleur, not the direct mounting interface, like several previous filings we have covered. The illustrations though, are just like we’d seen before.

SRAM Mechanical T-Type Transmission derailleurs, inner hub axle detail

That said, a few other previous patents also directly addressed this “Rear gearshift mechanism for coaxial installation” solution. What’s new since those as far as I can tell, is SRAM is now defining more clearly how the new direct-mount derailleur butts up directly against the rear wheel’s axle endcap, and better guides it into place. This could be an update for easier wheel installation. Or it could possibly remedy the issue where current T-type derailleurs can be poorly aligned or misaligned in the frame because of the crash-proofing slip design that allows them to rotate out of the way of an impact. But since there is no conventional B-tension screw, it is not always easy to be 100% sure that the derailleur is correctly realigned after such an impact.

SRAM Mechanical T-Type Transmission derailleurs, rear section view

Interestingly, even though the T-type direct-mount should ensure ‘perfect’ cassette alignment like with AXS Transmission, it looks like these new SRAM Mechanical Transmission derailleurs will get hi/low adjust screws again, based on all of the patent drawings.

I suspect we’ll have to wait for the final SRAM Mechanical Transmission launch to get into those details.

When is it coming?

SRAM mechanical transmissions are coming soon with both NX and SX Transmission derailleurs, eMTB teaser

I’m not going to out any bike brands here, because that doesn’t add anything to this still-developing story…

But what I can say is, there is at least one big bike brand out there with product page right now promising a new spec of a current model with “New SRAM Eagle Transmission” set to be available from March 27, 2025.

And how much will it cost?

SRAM Mechanical T-Type Transmission derailleurs, rear view

That new spec also happens to sell for a full 2000€ less than the same model spec’d with a SRAM GX AXS Transmission (more premium suspension spec, but also still alloy wheels).

A SRAM GX AXS upgrade kit only costs you about 600-650€, so obviously you aren’t going to save two grand with a mechanical SRAM Transmission. But what it probably means is that you’ll start to see Transmission-equipped bikes and ebikes selling around the same pricing level as you would see with current mechanical GX Eagle or even cheaper than Shimano XT.

SRAM.com

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Tom Wenzel
Tom Wenzel
11 days ago

Bueller (i.e., Shimano)? Bueller (i.e., Shimano)?

Shafty
Shafty
11 days ago

Who asked for this except PMs looking to fill their product lineup? T type with SX? Really? Guys, it’s a bit early for April Fools.

Veganpotter
Veganpotter
11 days ago
Reply to  Shafty

More and more manufacturers are going to build their frames with UDHs. Even their low end bikes. This will allow some cross compatability and easy upgrading.

jon
jon
10 days ago
Reply to  Veganpotter

frames designed around Direct Mount standard have been cross-compatible with traditional hangers, I.E. UDH for at least 5 years. that is—upgrading to a direct mount/transmission rear derailleur has not heretofore been an issue nor has cross-compatibility.

Shafty
Shafty
8 days ago
Reply to  Veganpotter

Sure, that’s obvious enough, but why do these bikes need 12 gears? The limiting factor isn’t mounting stiffness, it’s general tolerances. Instead of reducing the number of gears, they keep SX at 12 speed, and hope the stiffness will make up for it. This is literally meant to check another box on a spec sheet.

Dinger
Dinger
8 days ago
Reply to  Shafty

Why not? It’s the direction all the good frames are going.

Pike
Pike
11 days ago

2025 Devinci E-troy lite will get Eagle 70 transmission (to replace 2024 NX build)

syborg
syborg
10 days ago

UDH is an abbreviation not an acronym. Acronyms are pronounceable like RADAR and LASER.

Someone who is paid to write should know that difference.

RMOR98
RMOR98
10 days ago
Reply to  syborg

It’s an initialism.

Someone who gets pedantic in the comments should know the difference.

mud
mud
9 days ago
Reply to  Cory Benson

You seem to dislike the UDH. IMO it was a great forward-thinking invention to increase the durability of mtbs and e-bikes. Flat-mount brakes, imposed on us by Shimano, had a more debatable benefit to the industry.

syborg
syborg
10 days ago
Reply to  RMOR98

My dictionary says: “The form to which a word or phrase is reduced by contraction and omission; a letter or letters, standing for a word or phrase of which they are a part; as, Gen. for Genesis; U.S.A. for United States of America.”

A letter standing for a word, like U for Universal, D for Derailleur and H for Hanger, is an abbreviation. Initialism is a type of abbreviation. I was using the more general term and you are also correct.

Balderdash
Balderdash
10 days ago
Reply to  syborg

I always pronounce it like /ʊər/D/h/. Does that make it an acronym for me?

Exodux
10 days ago

This is great news, however I’d like to see this as an option for GX, XO and maybe XX in a non-electric version. Don’t get me wrong, I use Sram’s electronic drivetrains on a few bikes and believe nothing works better, but if Sram can build the same strength and simplicity( after Transmission is set up) into a mechanical drivetrain, I think this is a win-win.
I wonder what Shimano is doing to combat the T-Type systems? I think they need to do something, although there drivetrains work pretty well as is.

Polk
Polk
7 days ago
Reply to  Exodux

Agreed. At least a GX level mechanical would be nice. I suspect that the market for XO and XX mechanical would be small, as most people looking for higher level components would probably go with electronic (though Shimano XT and XTR seem to sell well, so maybe that’s not true).

Speaking of Shimano, it’s is kind of in a weird spot. Their drive trains work great and arguably don’t really need updating, but the market is fickle and constantly wants the “latest greatest,” even it’s not much of an improvement.

Dinger
Dinger
4 days ago
Reply to  Polk

Good ol’ Shimano XT soldiers on. It’s reliable, light, durable, there’s no batteries to keep track of and works very well. Decent SRAM cassettes and chains are also unacceptably expensive and breaking a $700 R/D would be an ender for many.

Last edited 4 days ago by Dinger
Dylan Sutton
Dylan Sutton
23 hours ago
Reply to  Exodux

I’m not a fan at all of rides depending on a battery being charged, in my experience cable operated shifting works well enough and is far more reliable. I’ve had more rides aborted due to flat (or lost) AXS batteries in the last 4 years alone than by broken hangers or derailleurs or derailleur cables in the preceding 30 years put together. My wife lost her AXS battery a couple of weeks ago, presumably the latch got opened in a minor crash and the battery fell off some time in the next few km of solid descending. After spending $90AUD to replace it I’m now on the lookout for someone selling an XO1 mechanical group to swap for it.

mud
mud
9 days ago

I don’t see a cable stop in any of the drawings. The cable pulley is angled towards the outside but no stop that I can identify.

Rik
Rik
8 days ago
Reply to  mud

It probably requires an UCS® (Universal Cable Stop) which is in such an awkward position that it’s only universal voor Eagle Transmission systems.

Ritxis
Ritxis
8 days ago
In Shimano patents prior to that of Sram you can see derailleur anchors to the frame like this......

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