Ratio Technology in the UK is back with another conversion kit solving drivetrain compatibility problems. This time, their Drop Bar Conversion for SRAM Eagle 70/90 lets you run a Full Mount SRAM mechanical derailleur and its T-Type 10-52T cassette on your 1x all-road or gravel bike with Apex shifters. A niche within a niche, this gets you a low-maintenance, fully mechanical, wide 1x range Transmission setup that’s durable and designed to shift under load, now for the first time on dropbars.
Ratio Drop Bar Conversion kit for SRAM Eagle 70 & 90
As a fan of Ratio’s gravel bike drivetrain problem-solving in general, and the simple durability and rebuildability of Eagle 90 Transmission in particular, I really love that they made this combo work.
While most of Ratio’s solutions are about adapting, upgrading, and re-using old drivetrain parts instead of throwing them in the trash, this is something different. Here, it’s about creating an all-new drivetrain transmission setup combining two of SRAM’s newest mechanical shifting components, which simply weren’t designed to work together from the beginning.
What do you need?
SRAM Apex got a mechanical 12-speed upgrade, and even both Xplr (up to 44T) & Eagle (up to 52T) range options when it debuted three summers ago. But in the years since, it didn’t get a direct-mount derailleur update, nor did it get the shift-under-load capabilities of the T-Type cassette & flat-top chain combo.
So, now Ratio has the fix. What you need is:
- A set of SRAM Apex 12-speed mechanical drop-bar shifters.
- Then, get either a SRAM Eagle 70 or Eagle 90 mechanical rear derailleur that direct-mounts to your UDH-compatible frame.
- Next, an Eagle T-Type Transmission 12-speed 10-52T cassette (there’s even one that fits on a classic Shimano HG freehub!)
- A Transmission Flattop chain (probably also a spare T-Type PowerLock quick link since they are the only ones that will fit, and are one-time-use-only)
- And then finally, the Ratio Drop Bar Conversion for SRAM Eagle 70/90
Note: The kit is not compatible with all those SRAM Exact Actuation 10- and 11-speed shifters that Ratio makes a bunch of other conversion kits to update.
How does it work?
The Apex shifters have a slightly different cable pull and no barrel adjuster, which is where Ratio comes in. Ratio’s conversion kit includes a CNC-machined 6082 alloy lower parallelogram link with an integrated cable fin, and a new composite rear-facing adjuster to dial-in your cable tension. All you have to do is swap out these two part from your Eagle 70 or Eagle 90 derailleur, then Bob’s your uncle.
A dropbar bike with Apex shifters mated to a SRAM Full Mount (direct UDH mount) mechanical rear derailleur.
Ratio Drop Bar T-Type Conversion – Pricing, real cost, and availability
Ratio describes the new conversion kit as “an excellent upgrade for bikes running SRAM Apex XPLR with an 11-44t cassette“. In reality, I see it mostly as a better option for cyclists looking to build up a more robust 1x drivetrain from scratch for adventure and bikepacking bikes. Those who don’t want to rely on batteries to shift, while deep in the mountains. People like me, who don’t want the bike industry to take away high-performance mechanical drivetrains.
The new Ratio Drop Bar Conversion for SRAM Eagle 70/90 costs £70 for their parts to convert your derailleur, or ~ $76 / 65€.
To make it all work, you’ll need the original SRAM parts listed above. Pricing should be about in $685 / 705€ total at retail for the SRAM shifters with brakes, Eagle 70 derailleur, HG cassette & E70 chain. ($270/295€, $140/135€, $235/240€, $40/35€, respectively.) But, I’d guess you can find at least some of that on sale if you are going to build it up yourself.
In any case, who can put a price on being able to shift your fully laden bikepacking bike under load, the robustness of that rebuildable Full Mount derailleur, or the peace of mind of not having to charge any damn batteries!