07-25-2014, 01:47 PM
Can we assume GPS to be 100% accurate? If there were 5 different GPS devices in the same car, would they all read the same after 100 miles?
Here are a couple questions I'd have that may account for some inaccuracies why GPS might record lower mileage. Sorry in advance for the rambling.
GPS devices rely on transmitted signals that can be interupted by trees, clouds, tunnels etc.
You're in tight twisties with tree cover, GPS loses signal for a couple secs, recovers and jumped across the ravine while you ran a hundred feet farther and back. It also does not track elevation well.
You go over a slight rise, down a little drop, and the difference is that you went a little farther than the crow flies.
Rear tire slippage. It occurs all the time, even though we don't feel it. It's the main (only?) reason tires wear.
One last point, a small one, maybe crazy. GPS is mounted at a fixed point, lets say along the centerline of the bike. As you lean, the GPS is moved a foot or two to the inside of the turn, and thus is going around a smaller radius, meaning a little less distance traveled.
Your mileage WILL vary.
Here are a couple questions I'd have that may account for some inaccuracies why GPS might record lower mileage. Sorry in advance for the rambling.
GPS devices rely on transmitted signals that can be interupted by trees, clouds, tunnels etc.
You're in tight twisties with tree cover, GPS loses signal for a couple secs, recovers and jumped across the ravine while you ran a hundred feet farther and back. It also does not track elevation well.
You go over a slight rise, down a little drop, and the difference is that you went a little farther than the crow flies.
Rear tire slippage. It occurs all the time, even though we don't feel it. It's the main (only?) reason tires wear.
One last point, a small one, maybe crazy. GPS is mounted at a fixed point, lets say along the centerline of the bike. As you lean, the GPS is moved a foot or two to the inside of the turn, and thus is going around a smaller radius, meaning a little less distance traveled.
Your mileage WILL vary.