Though smaller, SRAM’s combinations roughly line up with the common 2x road gearing combinations. The experimental errors and incorrect assumptions found in this study have been well documented.” This study (incorrectly) claimed that increased tension increased efficiency. “The only reason I can think of that SRAM might claim is because of a paper from the 1990s, which I mentioned above. Many people still remember that paper, and incorrectly site it. Unfortunately, there was a paper from the late ’90s that stated the opposite. In an emailed response, he said: “We have lots of recent data (last 10 years) showing larger-diameter rings and cogs are more efficient than smaller-diameter rings and cogs, given the same final gear ratio. I reached out to Jason Smith, Ceramic Speed’s chief technology officer, who has spent hours studying and analyzing drivetrain efficiency in his Friction Facts lab, for his take on how the size of a drivetrain’s rings and cogs affect efficiency. Here’s what a 2x disc brake group with power meter weighed on my scale: SRAM also stated that a Force-level version of eTap AXS will be released later this year. There’s also a new gearing scheme, a damper in the pulley cage, increased tire clearance, integrated chainrings and power meters, 1x drivetrain options, and a slight change to the shape of the brake levers. The most prominent is the jump to a 12-speed cassette, which brings with it a new driver-body standard, and a new chain. There are significant changes to the gearing. It also provides improved customization and control from SRAM’s AXS app. This means you can control the new Eagle AXS mountain bike derailleur, and the new RockShox Reverb AXS dropper post from the Red eTap AXS controls. The new Red eTap fits into SRAM’s AXS (say “access”) ecosystem of interconnected parts. Almost everything is new, the exceptions being the brake calipers (rim and disc) and hood shapes, which carry over from the previous generation and get only graphic updates.