Inconsistent Garmins

For Grandma’s, I opted to wear my 305 on my right wrist and my 405 on my left. I commenced each watch just as I crossed the starting line. While I refrained from recording mile splits, I did manage to record a split at the halfway point. The 305 recorded a 13.1-mile time of 2:46:18, while the 405 achieved a 13.1-mile split of 2:44:56 (a mere two seconds less than the reported actual race time). Notably, both watches indicated my finishing time within two seconds, matching the start time.

The 305: The 405                       .

Distance 26.37 miles Distance 26.22 miles

Started at 7:35:21 AM Started at 7:35:19 AM

Half Marathon 2:46:18          Half Marathon 2:44:56

Finish time was 6:04:40          Finish time was 6:04:42

Total ascent of 3,056 feet Total ascent of 3,285 feet

Total descent of 3,162 feet Total descent of 3,395 feet

Heart rate readings were the same

Consequently, the course on the right side is longer and features more hills than the left side. Is the 405 more accurate than the older 305? Is the reception on the left superior to that on the right?

Nevertheless, I will assume that this is a scientific phenomenon, and scientific knowledge is inherently imperfect, regardless of our efforts or expectations for perfection.

Carry on my friends, carry on!

Comments from my original blog - I merged the blogs.

Beth

At least the course was just 26.2. One of the marathons I ran was 0.7 longer. Ugh! I'm surprised the watches didn't come out to the same distance.  Thursday, June 25, 2009 at 10:02:26 PM CDT

Scott Mark

The 405 antenna is advertised as being better than the 3xx, but GPS elevation is NOTORIOUSLY bad, and I think it generally exaggerates high. Back in the www.motionbased.com days (before it was bought out and became Garmin Connect), one of the options they had was "elevation correction," where they traced your route and based elevation on topo data. I don't know if GC does that or not.  Wednesday, July 8, 2009 at 11:41:10 AM CDT