9 replies to this topic

[minimejim]

Hi i have just fitted my center speedo 130mph one. what colour drive that goes into the gearbox for measuring my speed correctly do i need?

thanks

[Guess-Works.com]

All depends on three things..

 

Speedo TPM ( Written under the odometer )

Final drive ratio

tyre size

 

and then a calculator...

 

http://www.guess-wor.../Tech/ratio.htm

Edited by Guess-Works.com, 30 March 2015 - 04:27 PM.

[minimejim]

Whats TPM?

My tyre size is 165/55/12

My engine is an mg metro 1275, pretty sure it's the same 4 speed thats in the mini 1275's?
It's A+

[minimejim]

Center clock

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[Guess-Works.com]

TPM - Turns per Mile

 

yours is a 1280tpm unit

standard final drive for the metro would be a 3.4, what the gear ratios are does not matter...

 

are you sure your tyre size is 165/55r12 ? and not 165/60r12

 

if it's the latter then you will be needing a 6 tooth worm and a 16 tooth pinion for the speedo drives.

[minimejim]

Ye my tyre size is 165/55 12

[minimejim]

Tyre

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[Guess-Works.com]

Must be using A048R's

 

in which case you will need a 6 tooth worm and a 17 tooth pinion.

[minimejim]

sorry im lost with this kind of stuff lol. so the green worm thats in needs changing and also something else? would that require he gearboxed being taken out? 

[Guess-Works.com]

The pinion is the plastic one which the speedo cable connects to, the pinion is driven by a worm gear which is driven my the mainshaft in the gearbox. You can change both with the engine in the car, but you will need to remove the radiator and the engine mount and bracket from beneath it to get to the worm drive..

 

If it has the standard metro drive in there, it'll be a 5 tooth.

 

Most common of pinions is the 17 tooth so you probably have one already, just count the teeth, don't rely on the colour

Edited by Guess-Works.com, 30 March 2015 - 05:28 PM.