As modern drivetrains are becoming increasingly siloed, with compatibility between brands evaporating and sometimes even compatibility between a brands own different lines questionable or fuzzy, Ratio continues to fight back. The small brand from the Lakes District builds drivetrain components, including its own derailleur, in house with broad compatibility. Now, that includes mechanical T-Type for drop bars.

Ratio Drop Bar Conversion kit: What is it?

Ratio’s latest release allows Eagle 70 or Eagle 90 derailleurs from SRAM to work with SRAM Apex 12-speed mechanical shifters. That means you can get a full, wide-range T-Type cassette onto your gravel or bike packing rig without having to go electric. Or, if you want to get really weird, mechanical T-Type shifting for your drop bar mountain bike.

Why? Well, there are advantages to Eagle 70 / 90 that are quite applicable off-road. It shifts reliably and without complaint even under heavy load. It is durable as heck, if you’re riding the rougher extremes of gravel. And it gives a wider range than any of SRAM’s 1x road cassettes. Compared to running T-Type wireless groups, Eagle 70 / 90 are also, uh, way less expensive.

Is the future of shifting mechanical?

Why do you need Ratio’s new Drop Bar Conversion kit? Because SRAM didn’t include a cable adjuster, which is useful for drop bar shifting. Most importantly, SRAM’s mechanical drop-bar shifters use a different cable pull ratio than Eagle 70/90 T-Type. Ratio’s clever fin design adjusts the cable pull ratio and adds an integrated barrel adjuster for on-the-fly adjustments.

Ratios’s Drop Bar Conversion kit includes a replacement link for the derailleur and a fin. Both are CNC machined in-house from 6082 aluminium.


Some notes and pricing

There are a few things you will need to run Ratio’s clever new kit:

UDH-compatible frame
SRAM Eagle 70 or Eagle 90 Transmission derailleur
SRAM Apex 12-speed mechanical drop-bar shifters
SRAM Eagle Transmission (T-Type) 12-speed cassette
SRAM Transmission (T-Type) Flattop chain

Ratio’s created installation videos to guide riders through the installation process, but promises it’s relatively straightforward.

The kit will not work with SRAM 10- or 11-speed drop bar shifters, even one with Ratio’s 12-speed ratchet upgrades.

Ratio’s kits are available from $76.34 USD / €65.42 EUR / $106.64 AUD or £70 GBP with all non-GBP prices calculated based on exchange rate at checkout.