2010 Infiniti G35 Speed

Whoever calibrated the speedometer entered some wrong numbers. Most commonly the tire size and axle ratio have to be entered. Sometimes oddball tire sizes aren't listed on the scanner's drop-down menu, especially when installing tires of a size never available as original equipment. In that case the mechanic will often guess with a similar size that is listed.

There is another legal issue to be aware of besides a speeding ticket. If the outer circumference of the tire and / or the offset is different than what was designed in by the engineers, the braking, handling, ride comfort, and steering response will all be compromised, and lawyers and insurance investigators know that. Any feeling of improved braking or handling is an illusion. Any competent lawyer WILL convince a jury that your daughter was partly responsible for the crash when the other guy ran the red light. They'll argue she was less able to avoid it, and they will be right.

I can elaborate on that if you'd like me to. This also pertains to people who raise their trucks and lower their cars. No suspension and alignment specialist would do this to their own cars or to someone elses. It's perfectly okay to install different wheels as long as they don't move the tread of the tire further away from the car. It's also okay to install those ridiculous-looking low-profile tires with larger wheels, as long as the outer circumference doesn't change.