10-52T on Drop Bars, No Batteries: Ratio Cracks the SRAM Eagle Compatibility Problem
Ratio's £70 kit lets SRAM Apex shifters run Eagle 70/90 T-Type derailleurs — 10-52T range, mechanical shifting under load, no batteries required.
A 520% gear range on a gravel bike, fully mechanical, shifting under load. That's what Ratio's new Drop Bar Conversion kit unlocks by mating SRAM Apex 12-speed shifters to the Eagle 70/90 T-Type derailleur — two components SRAM never intended to work together.
The problem Ratio solves is cable pull. Apex shifters pull a different amount of cable per click than Eagle derailleurs expect, and they lack a barrel adjuster. Ratio's kit replaces the derailleur's lower parallelogram link with a CNC-machined 6082 aluminum piece featuring a redesigned cable fin that corrects the pull ratio, plus adds an integrated adjuster for dialing tension. Swap two parts, route your cable, done.
Why bother? The T-Type system was built for mountain bikes getting hammered. It shifts cleanly mid-pedal-stroke when you're grinding up a steep pitch loaded with frame bags. The full-mount derailleur bolts directly to a UDH hanger with fewer pivot points to slop out. And the 10-52T cassette gives you a bailout gear that SRAM's road-focused Xplr groups can't match — useful when your "gravel ride" turns into a hike-a-bike unless you want to destroy your knees.
The real cost math: Ratio's kit is £70 (~$76). But you're also buying Apex shifters with brakes (~$270), an Eagle 70 derailleur (~$140), a T-Type cassette (~$235), and a Flattop chain (~$40). That's roughly $760 all-in for a complete drivetrain — not cheap, but still less than SRAM's wireless Rival XPLR group, and you'll never charge a battery or wonder if a firmware update bricked your shifting. The tradeoff is weight. Eagle 70/90 derailleurs are heavier than road equivalents, and that 10-52 cassette isn't svelte. If your gravel bike doubles as a Tuesday night crit machine, this setup doesn't make sense.
For the rider building a dedicated adventure rig — bikepacking trips where durability and repairability outrank grams — this fills a gap SRAM left open. You need a UDH-compatible frame, and the kit won't work with older 10/11-speed Exact Actuation shifters even with Ratio's ratchet upgrades. But if you've been waiting for a wide-range mechanical option that shifts like it means it, this is the only game in town.
