Quarq DFour Power Meter Crank Arms BB30

Though Quarq is technically part of the SRAM family SRAMily No, we wouldn't do that to you., the BB30 DFour Power Meter Crank Arms prove that the brand doesn't take a HatfieldMcCoy approach to inter brand compatibility. The DFour is, essentially, the DZero model but with one fewer chainring bolts and a bolt circle diameter BCD that fits Shimano's latest generation of 11 speed road chainrings, specifically Dura Ace 9000, Ultegra 6800, and 105 5800. That means that, with the exception of the latest Dura Ace 9100, the DFour is compatible with every 11 speed road drivetrain Shimano has engineered to date, so fans of the Japanese company aren't relegated to choosing between more expensive or less accurate power meter options. The BCD may be Shimano, but the crank arms themselves are all SRAM. They're built with the same Exogram construction process used in the brand's top groupsets, so they're around 200 claimed grams lighter than the aluminum model. The BB30 version of the DFour also ships with the spacers and wave washer hardware required to install it in a BB386EVO bottom bracket a bottom bracket standard that the aluminum DZero isn't compatible with. Except for that compatibility difference, the DFour incorporates every piece of technology Quarq crams into the DZero. Chief among these is the power meter itself, which saw a healthy amount of retooling. Overall, Quarq claims that 150 documented improvements inform the evolution from the previous models to DFour, but the most important is to the heart of the meter itself: the strain gauges and measurement circuitry. It still incorporates five strain gauges strategically placed throughout the spider in order to measure the Newton meters you're throwing into the pedals. It's also still got the same claimed accuracy of 1. 5%, so its numbers are 0. 5% more accurate than most meters, but the new design requires less correction in order to maintain accuracy in drastic temperature changes. Fewer corrections m...