KPH speedometers

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Princess Valiant

Princess Valiant

A.K.A. Rainy Day Auto
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Anyone know if a regular speedo can be converted to KPH or would it be something that would nearly impossible to do??
 
When Canada converted to the metric system there were lots of "conversion" methods and kits on the market ranging from small decals that were stuck on the clear plastic or decals that were applied to the actual face of the speedometer to mechanical devices that were installed on the speedometer output gear on the transmission. They were commonplace in the early to mid 70's, but I haven't seen one in years.
 
Saw a kpm speedo here for sale a few years ago, 0 to 250. No actually marking that it was kph that I saw.

Is the reason to have a kph speedo because you are going to be driving in kph countrys?

If not you could just replace the faceplate and do the mental conversion. 120kph is about 75mph

I would say that a speedo shop could do the conversion.
 
The problem with just re-decaling the speedo is that while it may read speed in KPH, the odometer is still clicking off "miles"... I would think a more accurate way would be to figure out the % difference between KPH and MPH and regear it at the trans, or use a gear reduction/multiplier on the cable. That way the speedo & odo are both changed the same amount, and the existing numbers can remain on the face. ??
 
Well, the NOS metric A-body speedo i have peaks at 200. Not kph, just 200.

You can have the face rescreened, but your calibrating is done at the transmission, via a speedo drive gear swap, just like any other speedo calibration.
 
There are stock A-Body KPH speedos (up to 240 kph) for all A-Body dashes of the sixties and early seventies - but difficult to find:

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My Dart should be kph,1976. Dont know about my 75 duster parts car though. I dont remember.
 
Professor Fate said:
The problem with just re-decaling the speedo is that while it may read speed in KPH, the odometer is still clicking off "miles"... I would think a more accurate way would be to figure out the % difference between KPH and MPH and regear it at the trans, or use a gear reduction/multiplier on the cable. That way the speedo & odo are both changed the same amount, and the existing numbers can remain on the face. ??
Click to expand...

Not 100% sure about that. You are assuming the both Decals are printed with the graduations in the same place. I think the numerals on the KM face are repositioned to reflect the proper kms/hr. I do not see a specific speedo gear for the 727, 904 and A-833 manual transmissions and these were available in Canada even into the early 80's ,long after we went Metric. They certainly did not change the transmissions or rear axles available in these cars / trucks and even later versions were modifications using lock up converter tech.
 
Are you planning to make tic tock videos of you driving fast, showing your KPH speedo?
 
I was able to find a NOS KM speedo for my 73 dart sport fairly easy. It was a swiss export car and someone had swapped in a MPH speedo sometime in its life.
It would probably cost more to convert one than to be patient and find the correct one.
 
Professor Fate said:
The problem with just re-decaling the speedo is that while it may read speed in KPH, the odometer is still clicking off "miles"... I would think a more accurate way would be to figure out the % difference between KPH and MPH and regear it at the trans, or use a gear reduction/multiplier on the cable. That way the speedo & odo are both changed the same amount, and the existing numbers can remain on the face. ??
Click to expand...

Difference between kilometers and miles is 1.6 (I mile equals 1.6 kilometers). In order to regear it at the transmission you just have to multiply the tooth count by 1.6. Sounds easy but unfortunately the highest tooth count is 45 afaik. That would mean you can only use this conversion method for very tall rear end gears and/or tall tires (45/1.6 = 28. If you would need a 28 tooth count speedo gear you can instead use 45 tooth gear and it would work in metric mode).
 
Maybe prowl the junk yards and see if you can find a Mexican (AutoMex) built A-Body.
All of their speedos were in KM/H.
The easy and best way in my opinion is to buy the face decal from Classic Industries for a little over 12 bucks, install it, and call it done.

I'm so used to doing the conversion in my head, I don't need to bother with a KM/H speedo in my cars.
I just use .6 as a multiplier and it's easy.
So, 60 MP/H = 100 KM/H. (roughly) 100 X .6 =60
And 40 MPH = 60 KM/H. (roughly) 60 X .6 =36
 
The math is already done via the decal, no new pinion gear needed if your transmission already reads correctly.
 
do they really have Kilometer odometers? crazy......its got 189,000 on it......Kilometers! Maybe just a different worm gear.
 
Since kl and miles are just a conversion ratio apart, theroretically you could just drop in the correct trans speedo gear and read kph on a mph speedo or mph on a mph speedo.

250mph speedo I'm liking it. Larger gear to slow the speedometer down. (IIRC)
Screenshot_20210513-085651.png
 
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