[Sharps40]

Actual speed/indicated speed -1 = X

X times 100 = percent high.

With your/my rear gearing (3.73 in the diff), each added speedo driven gear tooth should be about 5% reduction in speedometer read out...so....

Percent High/5 = Number of additional teeth needed on the driven gear to correct your speedo.

For example, this morning my speedo indicated 70 mph, Garman says actual is 55 Mph.

55/70 = .7857

.7857 - 1 = -.2142

.2142 X 100 = 21.42% error

21.42/5 = Need to install a speedo driven gear with 4.28 additional teeth to slow the reading down to correct speed.

At least, thats the theory. I'm gonna count teeth on my existing driven gear, measure the length and gear diameter and purchase either a T5/T10 driven gear or TH350 driven gear and driven gear houseing with 4 additional teeth on it.


Or ya can divide difference by actual and get a different figure with less math....in this case..

15/55 = 27.2% error....so given the internet myths and the possibilty the the common 26.7% ratio reducer is for sale, which do ya think is right? We'll see.....