Okay, you guys got me to thinking so I started doing some calculations,
including some real life measurements. I found out all is not as it should
be and so far no one can explain it, not DC, not Goodyear, so we're off to
the DC engineers. Let me show you what I've found. If you don't like
numbers you better delete this 'cuz that's what follows:
DC Actual Actual
RPM Tire Size Aspect Dia Cir RPM Miles Traveled
760 215/75R15 161.25 27.7 86.99 728.3 1.043
729 235/75R15 176.25 28.9 90.75 698.2 1.044
755 255/65R15 165.75 28.1 88.23 718.1 1.051
750 255/55R17 140.25 28.0 87.92 720.7 1.041
689 31X10.5R15 31.0 97.34 650.9 1.059
My tires are Pirelli Scorpion Zeroes 255/65R15, actually measured:
755 87.80 721.6 1.046
According to DC, they will check it out. Someone may or may not get back to
me specifically. If something were to change in the PCM tables a TSB would
be opened and a flash would be made available for the correction. In
addition to this I will have my speedometer/odometer verified to see what
kinds of differences are there. If I see a difference, that information
will be forwarded to DC as well. For those of you doing the math there
would be variances for the differences in air pressure but that should not
make a 4-5% difference.
Ron
00 PB SLT QC 4X2 5.9 46RE 3.92 LSD
For modifications see my DML Profile (URL follows)
http://www.twistedbits.net/WWWProfile/dakota/Kw9pV1EkFeOYY
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