Superlift TruSpeed Speed Signal Calibrator

When using larger than stock tires, the speedometer will not

read correctly. This, in turn, also affects the odometer and the

transmission shift points. To correct the speed signal, Superlift

has made a calibrator which alters the signal sent to the

speedometer, and other components. The box they've made,

called the TruSpeed, has two settings that can be set for

different sized tires. There are two dials, corresponding to each

setting of the switch, which are used to set the diameter of that

specific tire set.



Installation requires only 4 connections. A power wire, ground

wire, and two wires which connect in line with the speed signal

wire of the truck. The speed signal wire is located between the

left side battery and the sheet metal on the fender side of the

engine compartment. Removal of the battery is almost imperative

to gain access to it. It is a gray wire with a black tracer. The

two wires coming from the TruSpeed must be connected to the

proper ends on the speed signal wire once it has been cut. After

all the wire connections have been made, the box can be secured

in a convenient location. I chose under the steering wheel, behind

the removeable panel.



UPDATE - 12 - 24 - 04

On a road trip today, I had a chance to see just how accurate

the TruSpeed had been set. At this point, I had only used an 8

mile stretch of highway, near my house, to dial in the TruSpeed.

I used a 90 mile stretch of highway to get the first reading. The

accuracy of the odometer was 0.79 miles too high, over 90 miles

traveled. This comes out to 0.87% off from perfectly accurate.

For the return trip I made a small adjustment. After another 90

miles the Truspeed was now within 0.50% of perfectly accurate.



UPDATE - 2 - 6 - 04