… but another persistent complaint was more serious. The Insight's skinny little Bridgestone Potenza tires (165/65SR-14) didn't do much for straight-line stability, making the car far too sensitive to vagaries such as pavement rain grooves, truck ruts, standing water, and gusty winds. "Very twitchy on the highway," commented one chronicler. "This car demands more attention to drive than most."
This trait was aggravated by the addition of a set of Bridgestone Blizzak snow tires. We have high respect for Blizzaks, but in this application they didn't work well in dry conditions. In fact, one logbook note flatly stated that the winter tires "ruin the car. It's virtually undrivable on the freeway on these big, tall, wobbly tire-tread blocks."
We began to suspect there might be more to the Insight's rather touchy behavior than just the tires and decided to check the toe settings. The theory, set forth by Squire Csere, was that with mpg as a be-all, end-all priority, Honda probably selected toe specs to augment same. And so it proved to be. Insights are delivered with zero toe at the front, minimizing rolling resistance but exaggerating the car's response to pavement irregularities and the other variables listed above. We experimented with a little front toe-in—just an eighth of an inch—and found that it had a profound effect on fuel economy, which deflated from 68.6 mpg to 63.2 at a steady-state 60 mph (these data were excluded from the official mileage tally). However, we did note improved turn-in and marginally better straight-line stability. Major improvements are hampered by the narrower rear track, which maximizes the likelihood that at least one of the four tires is riding on a poor section of pavement.
