speedometer ratios?

im looking into buying a small speedometer with indicators built in to clean up the look of my 78 kz650. Not sure about the whole t ratio thing though. What ratio should i get? ,and why?

I was looking for the same info for my KZ750.

Seems it doesn't matter for speedometers, but for my tach, I went with a 5:1 ratio

Does anyone know the K-value of 19" Kz750 Ltd '84?

Will replace the speedometer but the mechanical ones are in 1,0 or 1,4 K-value

How do you calculate the k-value of a mechanical speedometer?
This instruction is valid for cycles, which have a hub drive on the front wheel resp. in the hub of the front wheel or where the distance rpm is taken off at the gear or the rear wheel.

1. The circumference of the wheel, at which the rpm is taken off, can be determined with a measuring tape or through scrolling on a straight line (u measured in cm).
2. Determination of the gear ratio of the existing pulse:
- Screw off the speedometer cable from the original speedometer
- on the now visible square of the speedometer cable you can put on a mark as counting help
- Do 10 turns with the according wheel (front- and rear wheel) and count the speed of the square of the speedometer cable (x)
3. Calculation of the k-value: Insert booth detected values u and x in the following formula:

k=10 * x/u

The result (rounded to one decimal place) gives the k-value of the speedometer. Please, detect the k-value carefully and exactly. An incorrect k-value will lead to a wrong indication of the actual speed.

I don't have my ride with me currently :blush:

greetings

So, had to replace the FW bearings and did some measurements:

The K-Value for '84 19" is- 1,4