Contemplating Rear Gear change - ZR-1 Net Registry Forums

XfireZ51 · 09-17-2011

I have a Pioneer AVIC in the car which is pretty neat. One of the features it has us a vehicle dynamics readout for stuff like amps, speed, lateral g, braking g's, compass. I rely on the speedo since mine is off due to the taller wheels and tires. I know that the rear gear is a 3.45. Comparing the speedo to the GPS, I calculate a 12-15% error. The tires are making the rear gear act as a 3.08. It looks like swapping a 3.90 gear would bring things back to operating as 3.45 gears would with 17" wheels. Thoughts?

09-17-2011	#1
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Contemplating Rear Gear change I have a Pioneer AVIC in the car which is pretty neat. One of the features it has us a vehicle dynamics readout for stuff like amps, speed, lateral g, braking g's, compass. I rely on the speedo since mine is off due to the taller wheels and tires. I know that the rear gear is a 3.45. Comparing the speedo to the GPS, I calculate a 12-15% error. The tires are making the rear gear act as a 3.08. It looks like swapping a 3.90 gear would bring things back to operating as 3.45 gears would with 17" wheels. Thoughts?