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speedo correction

Posted: Sun Jan 22, 2017 8:28 am
by jamesmdavis
Good Morning Group - I am about to change out the rear end gear ratio from 5.125:1 to 4.625:1 for better driving characteristics. ( It is supercharged.) How does one go about changing the speedo/trans to acomodate this change to maintain accurate speed indication? Thanks in advance.

Jim Davis
TC 7225
Houston

Re: speedo correction

Posted: Sun Jan 22, 2017 9:01 pm
by Tom Lange, MGT Repair
You either send your speedo to one of the rebuilders, and tell them which ratio you now have, and hope.

Or, you contact Speedograph Richfield in the UK, give them the ratios, and they will make up an adapter. (There is someone in the US who does this, but I forget who.)

If that's too much money, I use a grease pencil on the speedo glass, to mark the new mph in 3rd and 4th gears.

Tom Lange
MGT Repair

Re: speedo correction

Posted: Mon Jan 23, 2017 6:16 am
by jamesmdavis
Tom - Would that be APT Instruments?? Jim

Re: speedo correction

Posted: Wed Jan 25, 2017 11:21 am
by Tom Lange, MGT Repair

Re: speedo correction

Posted: Wed Jan 25, 2017 1:01 pm
by Steve Simmons
Tom Lange, MGT Repair wrote:Or, you contact Speedograph Richfield in the UK, give them the ratios, and they will make up an adapter. (There is someone in the US who does this, but I forget who.)
Butch Taras makes them here in California.