MPH to KMH Speedo conversion - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TONY2000 · 08-03-2012, 02:32 AM

Do any of you Guys have any info on a bolt in conversion for a 67 C10 to convert speedo to KMH from MPH ??

SS Tim · 08-03-2012, 03:45 AM

The best way would be to find one of the export speedos and Mexico seems to be were the few on the board are from. Sorry but I don't have the factory part numbers. A quick and dirty way would be to use a ratio converter of about 1.6 to 1 on the speed cable as often found on large tire equipped 4x4s. It would help keep you at legal posted speeds while preserving the American truck look at shows. The downside is you could easily bury the speedo needle while cruising at 100kph. Or step it down the same way about .8 to 1 and mentally double the indicated reading. Say 50mph would be 100kph. We kicked these ideas around among my engineer friends during the early 80s under the specter of "going metric" on highway signs. Of course re-screening (or commissioning) a repro. speedo lens and the .8 reduction box together could make a nice cottage industry product for you. But then you would have to send me a freebie lens for my collection. :-)

TONY2000 · 08-03-2012, 07:46 PM

Cheers for the info.
I think i have a solution found in the UK, ill let you know if it works out ok.

08-03-2012, 02:32 AM	#1
TONY2000 Registered User Join Date: Jul 2011 Location: Victoria Australia Posts: 15	MPH to KMH Speedo conversion Do any of you Guys have any info on a bolt in conversion for a 67 C10 to convert speedo to KMH from MPH ??

08-03-2012, 03:45 AM	#2
SS Tim Registered User Join Date: Aug 2010 Location: Edwards, CA Posts: 7,503	Re: MPH to KMH Speedo conversion The best way would be to find one of the export speedos and Mexico seems to be were the few on the board are from. Sorry but I don't have the factory part numbers. A quick and dirty way would be to use a ratio converter of about 1.6 to 1 on the speed cable as often found on large tire equipped 4x4s. It would help keep you at legal posted speeds while preserving the American truck look at shows. The downside is you could easily bury the speedo needle while cruising at 100kph. Or step it down the same way about .8 to 1 and mentally double the indicated reading. Say 50mph would be 100kph. We kicked these ideas around among my engineer friends during the early 80s under the specter of "going metric" on highway signs. Of course re-screening (or commissioning) a repro. speedo lens and the .8 reduction box together could make a nice cottage industry product for you. But then you would have to send me a freebie lens for my collection. :-) __________________ Thanks, Tim * VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID Blazer SPID Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders Do you have a 1972 Plaid Pickup? Plaid Blazer ** Plaid Suburban

08-03-2012, 07:46 PM	#3
TONY2000 Registered User Join Date: Jul 2011 Location: Victoria Australia Posts: 15	Re: MPH to KMH Speedo conversion Cheers for the info. I think i have a solution found in the UK, ill let you know if it works out ok.



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