LE / SE tire options (17" rim)

I ended up going with Contiental TrueContact Tour 54 in a 215/55R17. My speedo runs fast by about 2mph. GPS indicates 50 when the speedo says 52. The tires do not yet have 300 miles on them there a signs of only minimal impacts to range and mpg. My primary mode is EV use around town. My daily range remains so far between 58 and 59 miles. If you factor in a bit of inaccuracy because of the speedo (.96%) that means my true range has been reduced to between 56 and 57 miles - not earth shattering. They reportedly have much better wet handling than the Ecopia. I'll see in a year how they compare in terms of wear!

 

Just to be clear - the 4% fast on the speedometer is not due to the tyre change. That would have reduced speedometer and distance readings readings by about 0.4%. The new tyres have a slightly bigger circumference.

And an deliberately high reading on the speedometer (arising from legal rules about speedometers) doesn't mean all the other readouts are skewed by the same amount, so a 4% "true range" adjustment shouldn't apply.

 

Yeah by my calculation the 215/55R17 has a mere 1.25 mm taller sidewall, compared to stock 195/60R17:

(215*.55)-(195*.6)=1.25

And the 19” stock tire, 195/50R19, has an outside diameter 11.8 mm more than stock 17”, a much greater variation:

((195*.5*2)+(19*25.4))-((195*.6*2)+(17*25.4))=11.8

I hammered out the above with an RPN (Reverse Polish Notation) calculator app thus;

195
Enter
.5
Times
2
Times
19
Enter
25.4
Times
Plus
195
Enter
.6
Times
2
Times
17
Enter
25.4
Times
Plus
Minus

And for a sanity check, verified here:

Tire Size Comparison

 

Well heck, so much for my logic. I guess perhaps my speedo has always been slightly different than the displayed GPS results but I was never focusing on it. Looking at "Tire Size Comparison" there is hardly any difference at all (.1, .2 mph). That's even better news that my range hasn't really been impacted ...yay!

Thanks for the comments.

 

Yeah I think someone else mentioned: speedometers display slightly high, by legislation, in a mostly-vain attempt to slow down cars and reduce carnage. The car knows the more accurate speed behind the scene (assuming stock tires), and the odometer should be accurate as well.

 

My observations in the past, with other cars as well, have been that the speedometer is high by 2-3 mph. Not a %.