A recent blog query from reader Josh posed this question: Forerunner 405 or 305 for multisport training? Here’s the straight scoop. The Forerunner 305 is our true multisport trainer because it’s optimized for a quick-release mount that lets you snap the unit from a wrist strap to a bike mount in seconds. The 305 also has a multisport mode, which allows you to switch between sport modes (running, biking or other) with one button press. You can customize the order of the sport modes and choose to include transition time or not. During the activity, you’ll simply press the lap button and the screen changes from your run settings (let’s say your main page is set up to show distance, time and pace) to bike settings (distance, time, speed). Your overall activity time will be recorded as well and the data will be linked together as one activity when you upload to our online analysis site. The 305 is available in a multisport bundle that includes the quick-release wrist strap and bike mount, speed/cadence sensor for the bike and a free year’s subscription to MotionBased (soon to be Garmin Connect).If you already have a 305, you can purchase a quick-release kit and speed/cadence sensor separately.

The new Forerunner 405 is our latest GPS-enabled sport watch with cool features like automatic wireless updates to your computer and touch bezel operations. The 405 is ideally suited for runners training for marathons and other road races. You can use the 405 for cross-training on the bike using the bike mount, though it’s not a quick-release design. You would have to place the 405 on the mount and fasten the band. The 405 is compatible with the speed/cadence sensor as well. There is no dedicated multisport mode on the 405, but you can switch to biking mode so that your activity will be tagged as biking when your data automatically uploads to the computer, but you cannot link running and biking activities together.

Hope this helps you choose the Forerunner that’s tailored to your training.