Trans Speedo Gear

[clazar]

I need help in getting the correct speedo gear for my car. 1970 RR auto, 3:23 rear & P235/60/15 tires on the rear. What speedo gear should I be using. The speedo in the dash is registering about 5 mph fast with the current one.

Thanks

 

[Kern Dog]

I need help in getting the correct speedo gear for my car. 1970 RR auto, 3:23 rear & P235/60/15 tires on the rear. What speedo gear should I be using. The speedo in the dash is registering about 5 mph fast with the current one.

Thanks

 

[kiwigtx]

This is also required...
https://tiresize.com/calculator/

26.1 inch tire

 

[kiwigtx]

This is also required...
https://tiresize.com/calculator/

26.1 inch tire

In these days of modern technology, it is easier to fine tune a speedometer drive by using the GPS readouts while driving.

The old days of driving at a set speed with a friend in another car are long gone. @clazar - you might find that one tooth either side might be needed to accurately tune your speedometer readout. Starting point is a 33 toothed gear.