Over the past few years, SRAM has introduced its much-loved T-Type, or Transmission drivetrains, which swap out the standard mech hanger for the Full Mount interface, bringing direct and slick shifting to its AXS and mechanical systems. However, the brand has now refreshed and reorganised its regular drivetrains with the Eagle S-Series, which retain the mech hanger, but also introduce the Half Mount design.

Comprised of three drivetrails, one AXS and two mechanical, the S-Series is built to work in tandem with SRAM’s outgoing non-T-Type offerings. So if you’re looking to update your mech, without shelling out for a full T-Type setup, the S-Series is the way to go. In fact, there are a lot of similarities as the S-Series drivetrains build upon the foundations of the outgoing models. With that, each crankset uses the three-bolt chainring interface, X-Sync 2 chainrings, and the cassettes with 520% range (apart from S100, which gets 500% range), get a lot of the same tech, such as the Full Pin technology and X-Dome design.

So if you’re currently running the SRAM X01 Eagle drivetrain, all of the S-Series kit will work as replacements or upgrades.

2026 sram s200 hero
2026 sram s200 hero (Image Credit: Sram)

To outline how the S-Series range sits with itself, S100 is the entry level, S200 is the high-performance mechanical option, whereas S500 brings wireless AXS shifting into play. None of these uses the Full Mount system of T-Type, but there’s something rather interesting going on with S100.

That’s the Half Mount Derailleur. Coming alongside a regularly hung S100 derailleur, the Half Mount design comes with “UDH bolt integration,” which promises to bolster the derailleur’s strength against impacts. Though as this uses a slightly different design to SRAM’s Full Mount systems, it still requires the use of a derailleur hanger, and it’s still adjustable via limit and B-tension screws. It’s also only compatible with UDH-ready frames.

Where things might get a little confusing is that the S-Series cranksets are built to fit slightly different bottom brackets. The S100 crank, available in 175mm to 155mm lengths, fits 118/73 Powerspline BBs, whereas S200 and S500 utilise SRAM’s DUB bottom bracket standards with DUB Wide spindles. So if you’re shopping around, mixing and matching, keep your eye out for the smaller details.

2026 sram s500 hero
2026 sram s500 hero (Image Credit: Sram)

It’s similar for the cassettes, too, as S100 uses an interface for splined freehub bodies, while the other two work with SRAM XD freehubs.

Finally, as with GX Eagle AXS, Eagle S500 is available as an upgrade kit, so you can grace your bike with wireless shifting without having to shell out for a whole new drivetrain. This kit includes the S500 AXS derailleur, a battery, charger, and AXS Pod Controller with a discrete clamp.

Compared to Eagle T-Type, the prices of the S-Series are much friendlier. For derailleur prices, expect to spend £380 on the S500 AXS mech, £130 for S200’s option, and £70 for S100’s derailleur. The S500 upgrade kit can then be picked up for £585.