Here It Is: SRAM Eagle Mechanical Transmission
Today SRAM released details on two new mechanical-shifting mountain bike drivetrains. Here’s the breakdown on the freshies.
SRAM Eagle 90 & 70 Mechanical Transmissions
Eagle 90 and 70 are fully mechanical systems – that’s no electronics whatsoever. It’s an ordinary cable that connects the derailleur to the shifter. Plus, from what I can see, they’ve pulled just about all the technology from the wireless electronic Transmission, including the Full Mount interface that negates the need for a derailleur hanger, and incorporated it into these new cable actuated mechanical units.
By appearance, the new derailleurs are very similar looking to their richer electronic cousins. Perhaps a little slimmer but still very robust looking, and, there’s a cable running out of them. Now, in case you missed it, the Full Mount interface (or UDH) is a unique way of clamping the derailleur around both sides of the frame which creates a strong connection between bike and derailleur, for better shifting. We first saw it when the electronic versions of Transmission were released. Along with more accurate shifting, this system also allows the derailleur to rotate backward in the case of an impact. It’s a tough and robust system that is well-proven on the electronic versions of Transmission and it’s a damn fine idea to run the same mounting system on these new cable derailleurs.
There’s a new shifter too, and it appears to have the same wonderful ergonomics as the previous mechanical shifters. SRAM tells us the changes to the shifter are mostly around the architecture, that now routes cables parallel to the bars so as to pair perfectly with the brand’s new stealth brakes for a clean cockpit.
Per groupset, two shifter variants are available. A single-click version that is mandatory for eBikes and a double-click shifter for analogue (100% human-powered) machines. We are told the cable actuation ratios have been updated which means previous generation cable shifters won’t marry with Eagle 90 and 70.
Around about now you might be wondering how strong the new derailleurs are. “As strong as the GX Eagle AXS rear derailleur,” – is what we are told. And if you examine the construction and layout it’s almost identical to the wireless T-Type, so it probably is just as strong. If things do go wrong, replaceable parts for the derailleurs are available.
There are some small differences between the Eagle 90 and Eagle 70 rear derailleur. The Eagle 90 uses the same Type 4 damper found on GX, XO and XX Transmission derailleurs whereas the Eagle 70 uses a new drag spring damper. Different materials also make up the inner cage and inner link, creating a weight difference of 20 grams, between the two.
In terms of crank lengths, Eagle 90 is available in a 175, 170, 165, 160 and 155mm version. Eagle 70 is available in a 175, 170 and 165mm length. The usual 30t, 32t and 34t chainring sizes are compatible across both options of cranks but riders looking for more, like a 36t or 38t, will need to run the Eagle 90 crankset. In terms of eMTB compatibility, both the Eagle 90 and Eagle 70 cranksets are available in an eMTB version.
Completing the drivetrains by pairing them with the brand’s GX Eagle Transmission Flattop Chain and Eagle Transmission Cassette, seems an obvious match. After all, this is the brand’s strongest chain, that is developed specifically for the added loads of eMTBs. For a quieter and more durable ride, the cassette is nickel plated, it has the wide 520% range, with larger 38t and 44t cogs that improve the steps, in the low end.
Also released, and paired with Eagle 70, is the more affordable XS-1270 Cassette in a black nickel chrome finish and a Flattop Chain, in a polished steel finish. A key conversation point and something that SRAM is doing with just about all their drivetrains is cross-compatibility — all the new pieces released today are cross-compatible with the existing Transmission components. So you can mix and match your components.
New SRAM Dropper Lever
Compatible with most mechanical dropper posts, the new lever features cable routing that complements the brand’s stealth brakes for a clean looking cockpit. SRAM says the performance has been improved too.
The Bottom Line, as I see it
SRAM tells us the idea behind the two new groupsets is to deliver two new rebuildable, reliable and affordable drivetrains to riders. From what I can see, Eagle 90 and Eagle 70 will offer most of the performance benefits of the wireless Transmission groupsets, at a fraction of the cost, and that’s exciting! Local availability is immediate and for exact pricing, chat to your nearest stockist. More sram.com //