How many teeth on a GKN speedo wheel?

[dnb]

I counted them once, but forgot how many there were
Does anyone know?

And can someone please confirm the GKN diff ratio is 3.33:1?

Thanks.

[spend]

Do you mean the 18 teeth on trigger wheel for the speed sensor mounted on the prop shaft. I don't know if they are standard (no of teeth) between the cars in regard of the LT77/T5 & ETB/CAI model changes.

There are some variations of the diff, I believe from the Tuscan Racer, but the road cars were all 3.3:1 according to my notes.

Dave

ETA: apart from typo..
I'm not sure if that 3.31 is accurate, I've seen others mention 3.1,3.3 & 3.7 as the ratios, maybe they were just talking about general gearing and not so accurate? I never really worried about the accuracy as my speedo is one of the adjustable ones. I think we are in danger of assuming what dnb is asking for (I was guessing it was for a new speedo..)

Edited by spend on Monday 11th February 18:18

[AntonyJ]

gkn is 3.31.
are you talking about the gearbox sender with regards to teeth ?

[Griffit]

Are there different types of trigger wheel with different numbers of teeth and can they be swapped over? I have a GKN diff but later style CAI instruments hence a 20% over-read at the moment as the speedo is presumably set up for the BTR type sender arrangement. My speedo is at Not-so Speedy Cables to enable recalibration at the moment but swapping the trigger ring to one with 20% less teeth might be quicker!