I just got in my 20 tooth gear from Mustangs Plus today and installed it. After tes driving it, I found that now it reads 58 mph when I am going 50. Previously it read 60 when I was going 50. Something isn't right. Can anyone help me?
Need a different gear. If you get one too small, it will wear out quickly. And unless you have just the right tire size, it will never match right up. You could buy an electric speedometer from AutoMeter etc and set it to work with whatever tire/gear combo you are using.
I don't know if it makes any difference, but the gear I pulled out was smooth where the clip goes and the new one was curved. It was also shorter, and not orange like I thought it would be. But it did have 20 teeth.
Ok, I don't think I can return it since I installed it. I guess I'll have to go to the local Ford dealer.
Here is a gear chart. To use it look under the transmission you have, select the number of teeth, and that gives you the prefix and suffix. The body number is under the transmission type. For example, a 17 tooth gear for a manual transmission would be part # C3DZ-17271-C
The bag that the gear came in says Speedometer Gear 3SPD + Auto C0DZ-1721-20. It just doesn't make any sense to me. That means it should be a 19 tooth pink gear for a manual.
Probably some aftermarket company made that gear and who knows were they come up with part numbers. I can find the formulas for calculation the gear you need if you want. I used them and this chart and got mine within 2mph
Yeah, I used the calculations and I have that chart in an issue of Mustangs and Fords and i calculated a 20 tooth gear. I think I'll just go to the ford dealership and ask for the part number C8SZ-B. I just don't know if I am going to be able to get Mustangs Plus to take back this gear since I have already installed it.
