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Item # SRM0304

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Item # SRM0304


When SRAM first introduced its groundbreaking 10-speed Red component group, the heart of the industry-shaking design was 1:1 Exact Actuation technology. In ordinary terms, this means that with each shift the derailleur pulls the same exact length of cable, regardless of what gear you're in. 1:1 is simple to set up, it stays in adjustment longer, and it provides laser-accurate shifting. This advancement sent competitors scrambling to one-up SRAM -- cranking it to 11 or going electric. SRAM's engineers didn't buy the hype, and instead of 'me too-ing,' they've put massive efforts into improving their 10-speed drivetrain. The result is that the Red Aero Glide Rear Derailleur benefits more directly from the lessons learned over the life of first generation 1:1 than if SRAM were to start from scratch.

The Red Aero Glide Rear Derailleur now has a clean, air-cheating, low-profile mounting bolt that's made of titanium to keep weight as low as possible. The long upper knuckle clears 28-tooth cogs, and it is made of extremely stiff forged aluminum to resist flex, which helps to maintain perfect gear alignment. The inner carbon fiber pulley plate has also been enhanced to resist flex, increasing rigidity for precise gear changes, and its low weight results in a light action.

SRAM continues to run their Black Box ceramic cartridge bearings in the pulleys. Ceramic bearings offer outrageous hardness and roundness in comparison to steel, which reduces mechanical drag by a substantial amount. After aerodynamic drag, mechanical drag is the leading source of power loss.

The pulleys themselves were a focus area for SRAM engineers, and they improved weight, durability, and operation. Coined AeroGlide, SRAM optimized the jockey wheel's profile so that the chain will glide more efficiently over the tooth profile as it threads through the cage. This helped silence a notably noisy drivetrain and enhanced chain movement across the cassette. Most would call it a day with those advancements and skip out early for a ride, but SRAM's R&D team developed an elastomer coating to further quell pulley noise.

The SRAM Red Aero Glide Rear Derailleur also receives a barrel adjuster for simple fine tuning, and because it continues to use Exact Actuation technology, it's compatible with all SRAM shift levers: Red, Force, Rival, and Apex.

Tech Specs

(cage) carbon, (inner links) carbon, (body) titanium
Cage Length:
Pull Type:
Compatible Components:
SRAM 10-speed
Claimed Weight:
133 g
Recommended Use:
road cycling
Manufacturer Warranty:
2 years

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  • Familiarity: I've put it through the wringer

Best rear derailleur - period. I just changed the pulleys, and you can use this with 11-speed SRAM 22! Excellent! :)

Avg. ride time: 5m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

Pretty Darn awesome

    First off setting this derailleur up was a snap.
    1. Set the high and low stops
    2. Pull cable pretty tight and cinch the bolt
    3. Dial out the barrel adjuster until shifts are snappy.
    4. Go on a ride confident your shifting will be awesome.

    For some reason the SRAM Red was a lot less finicky to setup than my other non-Red derailleurs. Maybe it’s the engineering but it might be worth spending the extra $ if you maintain your own bikes, cause working on the good stuff is easy.

    Other than that this thing is light, sculpted, elegant, and my drivetrain is quieter now (must be the jockey wheels)

    Minus one star for the silly price tags on this stuff, if it breaks I will have to sell my son's braces.