That's a possibility. I have a Canadian 2000 Subaru OBW, and it's speedometer is primarily km/h, with mph the secondary scale. I find my km/h matches within 1 km/h of the GPS reading (also in km/h). Try switching over to km/h on the GPS and compare it to the km/h markers on your US Subarus. Maybe the km/h ratings are more accurate?
Yousuf Khan
I never heard about there being an (almost) world-wide vehicle regulation to overstate the speedometer speed reading. Doesn't even seem to be followed universally if there was such a standard.
Yousuf Khan
I did this today, indicated 100 km/h, speed on GPS: 96 km/h, so it is closer than mph.
The idea I had was in the software, if it was based on metric. On Siemens
840D controls in the machine tool industry, all calculations are done in metric. So if program is input in inch, it converts to metric and processes the program. Under certain scenarios, this conversion of 1 inch = 2.54 mm causes a cumulative error to take place and parts are no longer in a nice grid, the further from 0 the are, the more they spread apart. There is a program we use to correct for this, or it is implemented in the post.Blair Baucom
2005 Subaru Forester XS
Vehicle models will not be allowed by the authorities, if the speedometer shows *less*. (Look at the WIkipedia article for speedometer.) The only possible technical response to make sure this does not happen is to make sure it shows a bit more even in the most unfavorable circumstances.
I had chimed in earlier on this thread, and had commented that my 95 subaru has an error on the speedometer. However, this past weekend I was driving my newly acquired 98 legacy, and had different results. My
95 has slightly smaller than OEM tires on it. My 98 has OEM size but not OEM brand tires on it. Compared to my aftermarket GPS, the speedometer was nearly spot on. The speedometer always indicated between actual speed and 1mph over actual. It never indicated under my speed.I've noticed that different tires of the same size are not actually the same size. I got some Toyo tires in the 195/50-15 size for my miata and they were wider than other 205 tires, and also a larger diameter than a Sumitomo 195/60, which it should not be. Then again that Toyo might come a little larger because they anticipate people shaving the tread down since it's a racing tire. I wonder how much this variability comes into play.
I also wonder if the g'mint insists on the = or < reading and max sidewall inflation pressure?
meh - I could live without a speedometer just fine. Least valuable gauge IMHO.
Carl
Crap-and-a-half, just saw this, my '03 H6 OBW is exactly the same way, speedo reads +4MPH all the time, odometer seems to be correct.
Dave
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