I learn something new every day!

Major DUH moment...I am apparently NOT as slow on the indoor bike trainer as I had thought. I noticed that even though the current speed on my Garmin (Forerunner 305) usually shows in the 14-16mph range at cruising speed, my average never is more than 13-13.5mph.

I also notice that that average speed will frequently drop to the 2-5mph range for several seconds, quite frequently, even though the cadence remains consistently in the 90-100rpm range on the middle ring.

I did some Google sleuthing and discovered that there is a way to shut-off the GPS sensor for indoor workouts. Apparently my Garmin was grabbing a satellite connection here-and-there and it was cancelling-out the cadence/speed/distance sensor from the rear wheel and messing with my average distance and speed--not in my favor. Ahhh...

The way to prevent this is to turn on the Garmin, hold down the mode button until it shows choices of workout (run, bike, other) and select indoor. Now the trick is to remember to set this back to outdoor and running when I do my next outdoor running workout.

Hope this helps someone else. I wish Garmin units shipped with an actual paper manual to reference in a pinch (I'm finding this criticism applies to a LOT of things, nowadays--I'm old skool).

So today's 20 mile trainer ride was likely closer to 21-22 miles. Huh. I look forward to accurate data in future rides. This will be important as I start training for my first duathlon in a week. At least the first month of my training will be indoors...and probably closer to 6 weeks. I can expect half of my 11 weeks of training to be on the indoor trainer. Thank goodness for DVDs and a massive flatscreen TV. That reminds me...I need to go pick up Zombieland!


  1. wait, do you need some sort of attachement to use this on a bike trainer? Like how does it measure your speed if you aren't going anywhere? I am an idoit when it comes to my forerunner, even though I've had the sucker for 3 years now, haha! I'm getting my bike and trainer next week, so this would be super helpful to find out!

  2. Yep, it has a little cadence/speed sensor dealie (which can be used with any Garmin that has wireless/HRM capabilities, I believe...like the Edge, which is specifically for cycling). The sensor goes on one of the chainstays, then there is a little magnet that goes on a spoke. Each time the wheel turns the sensor records a revolution. With the GPS randomly picking up connections it really messed my speed up, though.

    My little Forerunner purchase 2+ years ago has really paid for itself. I was pretty geeked when I realized that I didn't need a separate bike computer and that it would work well with an indoor trainer.

  3. ohhhhhh ok so I need to buy an extra piece. Got it! Thanks Kirsten!

  4. Yep, this is what you are looking for:

    You can also get a quick release strap and bike mount for multisport races--makes it easy to pop it off your wrist and onto the bike, or vice-versa.