Sigma’s latest version of the Rox mountain bike computer tracks all the essentials -41 to be exact- with some interesting new features that make the $229.99 price not so much of a shocker.
All the expected speed, distance, maxes and whatnot are there. What sets the Rox 9.1 apart is its ability to measure gear inches, which they call “expansion” by comparing speed and cadence to determine the gear ratio. For a racer, this lets them compare various perceived exertions with actual heart race, cadence and gear ratios to determine the range where they perform best. It also helps identify duplicate gear ratios between chainring/cog combos.
On top of that, it measures power. Yes, for under $250, you get a computer that measures power, but here’s the catch: It’s most accurate when climbing and it’s really an estimate based on rider/bike weights, body size, gender and a few other factors that you input. Even Sigma’s marketing director Gindi Orloff admits it’s more of a “just for fun” feature, but combined with the HR, cadence and other features, it helps paint a broader picture without dropping four figures to get into the power game.
Lastly, the Rox 9.1 can record your rides (distance and speed, not GPS info), which is uploaded into their Data Center program along with all the other info. From there, you can create a logged ride and reupload that info to create a ghost race. Once loaded, simply start the virtual race at your usual starting point for that particular ride and it’ll tell you if your ahead, behind or on pace compared to your prior ride.
The 9.1 comes with both cadence and speed sensors, HR chest strap monitor and docking station and Mac/PC software. The 8.1 loses a few of the features, in particular the ghost race, and doesn’t include the docking station.