2012 SRAM Red: Shifting To The…
SRAM’s first complete overhaul to their premier Red groupset greatly improves upon the three weaknesses of the original kit. Although they haven’t created new triathlon shifters or followed the trend to electronic shifting, 2012 SRAM Red brakes stronger, front shifts faster (much faster) and makes less noise than its predecessor. Front Shifting The improvement in front shift performance from the original Red kit to the 2012 version is simply astonishing. SRAM engineers transformed this critical aspect of component performance from the group’s biggest weakness to one of its greatest strengths. A light flick of the new slightly larger shift lever catapults the chain from the small ring to the big without any grinding, skipping or mechanical feedback. The chain just goes. SRAM dramatically changed the front derailleur and the chainrings to achieve this outstanding shift performance. The original Red front derailleur cage was made of titanium and flexed when shifting. Some professional road cyclists and triathletes sponsored by SRAM use the lower level Force front derailleur because it has a stiffer steel cage and shifts faster. The new Red derailleur is feather light, but doesn’t sacrifice stiffness. Instead of using a single material to construct the cage, SRAM used steel, aluminum and even a little carbon to build a cage that is light, stiff and pretty. The wall of the derailleur cage closest to the frame is steel. Although it’s heavier, building this critical section of the derailleur with steel helps the cage keep its shape when pressed against the chain rather than giving way slightly, which can slow shifting. The front of the cage is forged aluminum. This material lightens the component and allows SRAM to shape the piece to a very specific subtle curve and give it a beautiful finish. The black inside portion of the derailleur’s tail is carbon composite press fitted and glued on to the steel segment. SRAM Design Engineer Mark Santurbane says this bond is plenty strong because the chain doesn’t pull directly against the carbon segment so there is very little stress on the bond. In addition to the changes to the cage itself, SRAM fundamentally changed the way the derailleur moves when shifting. Most derailleur cages move straight to the side when shifted from the small ring position to the big. If you marked the position of the walls before and after shifting, they would be parallel to themselves. Although this simplistic movement can execute an accurate shift, existing systems using this derailleur movement require an intermediate front derailleur position to prevent the chain from rubbing against the chain in all gear combinations. SRAM added a twist in the front derailleur’s shift movement that allows the system to rapidly jump gears and eliminate the middle position entirely. The tail of the derailleur is pointed toward the center of the cassette whether in the big ring or the small. When the derailleur drops to the small ring position, the tail of the cage—the rearmost part—doesn’t move in toward the bike as far as the front of the cage. As a result, the cage ends up pointing slightly outward from the bike. This unique movement prevents the chain from rubbing in almost any gear combination. We were able to get a tiny amount of chain rub when in the 39-11 combination, but there wasn’t a whisper in any other combination, even while cross-chaining in the big-big 53-23 gear combination. Although the ability to cross chain with impunity is a major bonus, the biggest improvement is simply the speed, ease and accuracy with which the kit up-shifts. Upshifting to the big ring using the 2011 Red kit required a bit of cajoling, but the 2012 shifts with amazing speed and precision. Since the middle trim position has been eliminated, a light flick on the shifter is all it takes. Front shifting felt amazing compared to any mechanical component kit, and shockingly close to the performance of Shimano Di2 electronic groups. The chain would shift from any gear combination and even under a lot of load. The chainrings are the other redesigned components that make this superior shifting performance possible. After much trial and error while working around the existing patents held by Shimano and Campagnolo, SRAM found a combination of ramps and pins that accelerate front shifting. The front derailleur comes with a chain catcher that can be adjusted independent of the derailleur to prevent the chain from falling off the chainrings onto the frame.
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2012 SRAM Red: Shifting To The…
