Hello -
I just did another GPS correction test :
Code:
Car Odometer GPS GPS/ODO % Correction
2007/06/19 19.00 19.6 1.0310 +3.1% (after purchased)
2007/06/19 36.15 37.2 1.0290 +2.9%
2007/12/01 30.40 31.2 1.0263 +2.6% (6 months later)
2007/12/05 31.40 32.3 1.0286 +2.9%
2008/10/08 34.1 35.1 1.0293 +2.9% (16 months later)
2008/10/09 35.6 36.5 1.0253 +2.5%
In the 2008/10/08 test, I wasn't being smart and did some strategic EOC, so I am sure that it contributed to the higher % (when you turn the key to the off position, the car odometer stops, but the GPS keeps right on chugging).
In the 2008/10/09 test, I was much more careful. I *like* that the % is going down over time. This is consistent with tread wear.
As stated before, I am sticking with a 2% error correction on my gaslog because I don't want to accidentally inflate (ha ha) my MPG numbers. Also, tire wear will eventually bring this correction down over time (i.e. always losing tread => always reducing tire circumference => always reducing odometer error over time).
Me happy,
.
CarloSW2