speedo recalibration

[Hatchy 23]

hey people ive been told for speedo recalibration you just have to change the little cog and theres 3 types. is this true and if so what are the tyre sizes to run for each cog?

[deankxf 20,294]

yeah, depends on what diff gears are fitted currently.

 

also if its an XF or later uses a different transducer which is 20% more pulses than XD XE one.

 

how far out is it? gears wont get it spot on, if its out 5km you will be lucky if you can get it closer with gears, usually one tooth different makes about 10% change.(10kmh ish measured at 100kmh)

[Hatchy 23]

well i havnt done anything yet but i was wanting to put 18" on the ute but increase the tyre size because i dont like to much rim so i dunno what else to do the rims i want only come in 18's

[deankxf 20,294]

fit the wheels if thats what you are happy to do(legal, looks, etc )

then do 100kmh with a GPS or similar and note what the speedo reads (it may read 90kmh when doing 100 for eg)

then remove the speedo gear and see what number of teeth are on it.. if it has 19 for egsample(most common for 2.92 diff) you can get a 18tooth gear and fit it, and it will make about close enough from what i have done near 20 years ago..  if its out 2 km or so you can pluck off the needle and reposition it just to make it safer not to speed but thats only if its close otherwise it will throw the rest out.. not sure if the ghia cluster is adjustable(i have one in bits here but cant see any adjustment)

 

failing that, you can get a speedo corrector kit(jaycar do one and some other brands do them also) and wire it in, will be able to get it spot on with one of them from what i hear.

[wagoon 2,429]

Also use a tacho and note what rpm , speed and gear your in. I have found that speedos tend to move around and can also jump but a tacho if using a good one is more reliable and accurate.