SRAM just quietly dropped something big. As of today, the entire old Eagle mechanical and AXS lineup — SX, NX, GX, X01, XX1, and all four AXS variants — is officially dead. In their place: three new groupsets called the Eagle S-Series. S100, S200, and S500. That’s it.
This is a massive SKU consolidation, and honestly, it’s probably the right call.
What Is the Eagle S-Series?
The S-Series is SRAM’s new simplified MTB drivetrain lineup for bikes running a traditional threaded derailleur hanger — not UDH. If you want UDH compatibility, you’re still shopping in the Transmission range. The S-Series is explicitly for legacy hangers, older frames, and OEM builds where UDH isn’t in play.
Here’s the short version of the three tiers:
S100 — Entry Level Mechanical
- 12-speed, 10-50t cassette (455% range)
- PG-1210 all-steel cassette, Shimano HG freehub compatible (huge deal for budget builds)
- Drag spring cage damper instead of a full clutch
- Crank starts at 155mm — short crank fans rejoice
- Shifter: $30 | Derailleur: $70 | Cassette: $85 | Crankset: $70 | Chain: $30
S200 — Mid-Range Mechanical
- 12-speed, 10-52t cassette (520% range)
- Type 3 clutch derailleur — proper trail-ready setup
- Matchmaker shifter compatibility (not just a band clamp)
- Shifter: $40 | Derailleur: $135 | Crankset: $100–$220 | XG-1275 cassette: $220 | Chain: $40
- Crank arms available separately as the S200 DUB Crank Assembly ($80) if you’re reusing an existing chainring
S500 — Entry-Level AXS Electronic
- 12-speed wireless, 10-52t
- The derailleur body is shared with SRAM’s Transmission AXS line — you’re essentially getting that hardware on a traditional hanger mount
- Overload Clutch (same tech as higher-end AXS derailleurs) — motor disengages on impact, returns to position automatically
- Compatible with existing road and MTB AXS shifters — serious crossover appeal here
- Carbon crank, DUB BB, Boost spacing
- Derailleur: $390 | XG-1299 cassette: $545 | S500 Crankset: $365 | Chain: $100
The UDH Half Mount — Clever and Cheap
One clever addition is the UDH Half Mount, a ~$10 accessory that bolts onto the S100 derailleur to add side-impact protection. Think of it like a derailleur guard but integrated with SRAM’s concentric axle mounting. It gives budget bikes on traditional hangers a bit of extra peace of mind — it’s the kind of thing that should have existed years ago.
Why This Matters
The old Eagle lineup was genuinely confusing. SX was notoriously bad. NX was mediocre. GX was good but had a half dozen variants. X01 and XX1 overlapped in weird ways depending on whether you went mechanical or electronic. Retailers hated stocking it, OEMs had headaches speccing it, and consumers had to do real research just to figure out which GX they were looking at.
The S-Series fixes that. Three tiers, one per job:
- S100: get on the trail without breaking the bank
- S200: proper workhorse for aggressive trail riding
- S500: gateway to AXS without going all-in on Transmission
The S500 in particular is interesting for the broader cycling world. SRAM is explicitly calling out gravel and road compatibility — pair the S500 derailleur with road eTap shifters and a 1x road crankset and you’ve got a cross-platform AXS build at a much lower entry price than anything SRAM offered before.
What This Means for Buyers Right Now
If you’re shopping for a new bike and see any of the old names — GX Eagle, X01 Eagle, NX Eagle — those are now legacy components and stock will dwindle. Replacement parts and support will continue for a while, but the new builds will be on S-Series moving forward.
If you’re upgrading an older bike with a traditional hanger, the S200 is the most interesting option. Full clutch, 52t compatibility, proper cassette — it’s essentially the new GX, and the pricing looks competitive.
If you’ve been eyeing wireless shifting but couldn’t stomach the price of GX AXS, the S500 is the first time SRAM has offered an accessible AXS entry point at this price level.
More hands-on impressions to come once we see these in the wild. But on paper, SRAM finally cleaned up the mess.
Sources: BikeRadar, Escape Collective
Product images courtesy of SRAM