How do you calculate 105 gearbox ratios?

[Martyn]

Being an Alfetta convert to 105 model I need someone to explain how to calculate gear ratios on a 105 box ( I think I know had to do it but need reassurance )
Thanks Martyn

[Colin Byrne]

what exactly are you trying to work out?
i've attached a table of overall gear ratios from the factory manual that might help you most LSD diffs are 4.1 final drive and most non-LSD diffs are 4.55

if that's not what your after just let us know

[Martyn]

Thanks Colin for response .
I shall elaborate on what I am seeking.
I have been offered a close ratio gearbox for my 105 and need to verify the ratios the seller says they are.
4th gear on the input shaft is constantly engaged with the layshaft/output . So on the set for sale the 4th gear input has 18 teeth mated to 4th gear layshaft with 24 teeth. Giving a ratio of 1.33. That is input turns 1.33 times to turn layshaft one complete revolution.
So if I count the teeth on each gear and divide the layshaft by the input and multiply by 1.33 this should give me the ratio of that gear?
'light blue touch paper and press send"
Thanks in anticipation.
Martyn
BTW Alfetta boxes much easier to calculate ratios ( but that's all!)

[Alan Hopla]

Martyn's,

These any help.

Alan.

[Martyn]

Thanks Alan very good info.
Application of your charts confirms my post that it is  the correct method.
Seems like the seller has a bit of explaining to do about claimed ratios.
Regards
Martyn