I looked back through the various wheel size threads but didn't see this particular question addressed: I recently bought a '98 wagon that the previous owner had put 15" ZX2 wheels on. The odo loses .3 over 5 miles and the speedo appears to read about 5 mph slow (Just based on other traffic, not checked with radar or timed distance). Q1-Do the taller tires/lower speed reading negatively affect any of the engine management systems? Q2-Back when I was running a Jeep, we could get a factory speedo gear toothed to compensate for larger tires. Is that possible on the Escort? If so, is it worth the time and money?