same as Title. my dad tells me theres a wire thats malfunction, but idk im not familiar with my camero yet. so what can be the problem? is it easily fixable by replacing the wires? or do i have to buy a new speedometer completly? help would be appreciated thanks (=

 

It depends on what year your car is, which you kept a secret.
1990 and up is electric speedo, 1989 and older is cable driven speedo.

 

ah im sorry, my Camaro is a 1992 RS, an is there any website that i can order the parts?

 

Does anyone know how to calculate the speedometer driven gear size?
I've tried several online calculators and im getting crazy numbers like 78 or 79.
Drive gear is 19
Axle ratio is 3.08
Tire size is 15
What is the correct driven gear size?

 

15" wheel size means nothing. You need the diameter of the rear tires. Once you know that diameter you convert that to circumference. 3.1416 X Dia. To explain that, if the tire was off the car and you marked it and rolled the time 360 deg around till you get the mark in the same place you started. This tells you how far the car will travel if the tire rotates one time. It would not matter if you had 20" or 14" rims it is the distance around the tire that counts. 3rd gear in an automatic is a 1:1 ratio and 4th gear on a T5. It is easiest to calculate speeds without over drive.
With the transmission is 1:1 all you need is RPM/Rear ratio (3.08) times how many feet the tire travels each rotation.

2500 RPM divide by 3.08 means your tire rotates 811.7 time per minute. Let say the distance around you tire is 5 ft, that equals 3246ft/min. That converts to 46 Miles/hour.

You could also just use your phone to tell you how fast you are going and look at the speedo. This would give you a ration. Lets say your phone says you are going 45 and your phone says 55, That is 45/55 ratio or a .818 ratio, depending on how you look at it the inverse may be true 55/45 .1222 Ratio.

 

Agree with Gorn, tire diameter is what counts and the rime size is of less interest in this context

I use the profile numbers to calculate, for ex a car has the original tire size 225/70/15 and I change to 235/70/15

which means; 235 * 0.7 - 225 * 0.7= 164.5 - 157.5 = 7mm difference,
that is, the car will sit 7mm higher with the 235/70/15 than with the original tire size 225/70/15, and the tire diameter will increase 14mm