1968 cortina "bullet" gearbox speedo drive

[rdssdi]

Looking for the speedo drive gear and shaft that fits into the transmission and drives the speedo cable. As I understand the 3.90:1 rear ratio should use a 25 tooth gear.

Thanks

Bob

[Brett Wilkie]

Here is a bit of info on the calibration.
http://www.duttonownersclub.co.uk/Membe ... _calib.pdf

Are you just looking for the gear with it's shaft only or do you need the alloy housing that it goes through as well? (just trying to clarify your needs)

[rdssdi]

It appears I need a blue or 25 tooth gear. There was a white gear in the trans that now has a portion of the gear stripped away.

I do not require the alloy housing. According to the TVR owner manual I have the rear ration is 3.89:1 and the car has 15 inch tires.

Bob

[Brett Wilkie]

A quick look at Ebay doesn't show any 25T gears for sale but I have seen green 24T
http://www.ebay.co.uk/itm/FORD-SPEEDOME ... 2582111e51
Can't see the colour on this?
http://www.ebay.co.uk/itm/Speedometer-d ... 4612e57e44

Have you calculated your rolling radius out fully? These cars normally had 13 inch rims and you are using 15 inch. Here is a really helpful calculator, just enter your tire and wheel info and it will give you the rolling radius as well as other info, you even get a visual of how the tire/wheel might look.
http://www.kouki.co.uk/utilities/visual ... calculator

You might find a different gear would work? Also check the condition of the gear on the trans output shaft, a lot of these were made of plastic too.