Introduced at Interbike 2014, the 4iiii power meter has come a long way very quickly. Originally planned as a DIY add on, they showed an even smaller unit at Sea Otter last year and introduced their factory installation option. Now, they’ve done away with the end user installation option and are offering two ways to get their power meter on your bike, both still starting under $400.
Even better, they’ve improved the accuracy of their power measurement by adding a third method of strain gauge measurement to the system. Called 4iiii Precision 2.0, they’re touting it as a “3D crank power meter” because it uses three strain gauges to measure the arm’s bending, shearing (pulling the pedal hole away from the spindle center) and axial deformation, with the latter accounting for odd angles of forces acting on the pedal (like if your knees bow way outward and your pedal isn’t being driven downward in a perfectly straight line…
The original version offered bending and shearing measurement, it’s the axial measurement that’s new. They said they had some customers that were getting odd readings because of their pedaling style, so their research found that measuring and compensating for varying axial loads lead to more accurate numbers.
The device is still just $399 for a left-side (single leg) unit, and you can either send your compatible alloy arm in and have them install it for your, or get a brand new Shimano 105 arm with it preinstalled for that price. The 105 preinstalled units are available now, the aftermarket install’s coming in July. Both use a new housing that removes the original hooks used for self-installs.
The new design also tees up their dual sided system, same as what Etixx-Quickstep has been racing. It’ll initially be only for Dura-Ace and starts shipping in July. They’re looking to add more SRAM options in the future, but at the moment you can get it on just about every Shimano crank starting at the 105 and XT levels, road and mountain.