From: rdenno@pacbell.net Date: Sat, 22 Mar 1997 19:09:50 -0800 To: a-powell1@tamu.edu Subject: Re: <280> Speedo Error The following is from my historical file on speedometers. You can change the relationship between the rear wheel circumference and the speedometer by changing the pinion in the transmission. If you need any help in the mathematics of this change, let me know. Regards, Dick Denno Subject:Speedometer Pinions Date: Tue, 21 Jan 1997 12:42:06 -0500 (EST) From: DugManney@aol.com To: z-car@taex001.tamu.edu Just replaced my speedometer pinion gear and replacement unit has one more tooth than the old one. Did a little homework and discovered that Nissan actually makes ten different pinions, each with a different number of teeth. Obviously the increase in the number of teeth will result in the slowing down of the speedometer reading. My question is how much? Other question is at what point would you WANT to change this gear. Naturally tire size (increasing or decreasing) would be one reason. Anyone have any other specific examples? Here are the different colors and number of teeth. How much (in MPH) difference are we looking at per tooth added to the gear does the MPH decrease? 16 tooth Speedo Pinion (yellow) (*My original) 17 tooth speedo pinion (black) (**My replacement) 18 tooth speedo pinion (blue) 19 tooth speedo pinion (white) 20 tooth speedo pinion (red) 21 tooth speedo pinion (purple) 22 tooth speedo pinion (orange) 23 tooth speedo pinion (green) 16-19t require standard sleeve assembly 20-23t require special sleeve assembly Thanks Doug Manney IZCC #337