Speedo MPH/KMH question

[fab]

Hi chaps. hope I explain this query correctly.
Lets pretend I have 2 speedo clocks.1 is in MPH and the other is in KMH. If I put the mph clock in place of the kmh clock will the speedo continue to act as MPH? In other words is it the speedo that controls the mileage recorded or is there some other mechanism (that differs between kmh and mph cars) within the car that tells the speedo how to record miles?
Theres fridays conundrum for yous :P

[2 live]

just the spacing/reading on the clocks will b diff mate....majority of clocks have mph/kmh on and the required readings are usually the larger.... i.e euro car will have kmh as main readout, uk car mph. would have thought evrything else will be same on both cars...i.e speedo drive/cable etc

[fab]

Top man.Thanks 2 live

[robi1000]

I'd say speed would be shown correctly, but distance wouldn't. There must be some kind of difference to covert between km and miles (probable different gears in the clocks).

[fab]

^
not on the gearbox then?
I have put a gearbox from a right hand drive willy into my left hooker. I should go for a drive and find out!

[Geeky]

I'd say speed would be shown correctly, but distance wouldn't. There must be some kind of difference to covert between km and miles (probable different gears in the clocks).

that would be odd as distance is simply Speed x time. unless the distance logger has nothing to do with the speedo cable?

[robi1000]

It is speed x time, but numbers on the dial can be spaced differently to compensate for 1.6 factor, distance can't be. Either it shows distance in miles or in km.

[Yanoo_]

The speedometer drive gear is 21/29 in all JC5-014. The difference is in the gear of the odometer.

[robi1000]

The difference is in the gear of the odometer.

That's what I meant.

[fab]

Yep lads went out today with the right hand drive box and my original KPH clocks and it was indeed registering in KPH, so it's in the clocks where it register's kph or mph.