Seedo drive gears
Turbo Mini Forums

Could anyone tell me what dpeedo drive gears should be used ( the number of teeth on each cog) for a standard turbo box with 3.1 final drive on 13"

http://i28.photobucket.com/albums/c248/spe...er1/mini007.jpg

If it a'nt broke don't fix it !!!!!!!!!!!!!!!!!!!!!

As long as the tyre rolling radius is not significantly different from the 145/70/12, then the standard set will do.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

i have given up with speedo's now and just use a satnav, my last box has a 1275gt speedo drive the current box i have is a mg metro unit but its horribly out at 40 im doing about 55mph =/. atleast with the 1275 box it under read

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

im using 6/16 gears gavin ,thats on a 3.1 and 165/60 12 tyres ,reads 2 mph slow at 70 apparently .
regards robert

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

You need to know the turns per mile of your speedo, if its the old center binacle type, it will be marked just under the odometer, just to the right. If its the later behind the wheel speedos, you need to diss assemble the speedo to get to the mechanism and the turns per mile is marked on the coloured plastic spindle gear on the speedo mechanism itself.

Use this little program http://www.minifinity.com/index.php?name=U...req=getit&lid=4, it is from Minifinity, but it is actualy a little gem. Input all the relevant info and it will calculate the nearest speedo drive ratio, from there you can work out which spindle and gear you need.

http://www.theminiforum.co.uk/forums/index...=turns+per+mile

Hope that helps

Edited by Sprocket on 10th Feb, 2008.

Try this web link Gav, it allows you to input tyre size and speedo type and then you can work out what drive gears you need.

http://www.tomsminisite.co.uk/speedo_calculator.php

Ive seen that link before, but there are still an awful lot of drive gear combinations missing, for instance, 3.74 FD with a 1300TPM speedo needs either 15/5 or 18/6 drive gears and niether of those are listed.

Also, I have a Smiths speedo (whether its off a mini or not) that is 1374TPM and again that is not listed.

I still feel its better to work out the actual ratio required and then find the best combination of drive gears.

I supose it all depends on how accurate you want to be

Cheer's chaps ! but on reading you're responses it's dorned on me that I'm using a 100mm Dia 120 mph Smiths speedo (I think from a Dolimite). On inspection of the speedo the only numbers I can find is on a little sticker on the inside 245-32, so any ideas what this denotes ? I'm uising 175/50/13 tyre's with a 3.1 diff. The best I've come up with is 7/17.

http://i28.photobucket.com/albums/c248/spe...er1/mini007.jpg

If it a'nt broke don't fix it !!!!!!!!!!!!!!!!!!!!!