5 replies to this topic

[mini-geek]

I've currently got a 3:44 diff and a close ratio gearbox and SC drops

3:44 is fine for the road but I want to be able to lower the FD ratio for sprints..

Now I understand that I can do this by just changing the primary gear and just taking the wok and cutch off to do this..?

So if that is right I can have a 24 input and 30 idler gear on all the time, and put a 24 tooth primary gear on for the road and then change it for a 22 for track use?

Or have I got the wrong idea?

Also can anyone recommend a place to get quality drop gears?

[Cooperman]

That is what SC drops were intended for, changing the ratio for different competition venues.

Mini Spares do very good quality drop gears.

[The Principal]

A little more complicated than you suggest, you need to remove the wok, flywheel and the flywheel housing (drain the oil, new gasket, clutch oil seal) the drop gears are between the alloy housing and the block/gearbox

 

Minispares sell the following sets -

 

22 tooth primary - 30 tooth idler - 25 tooth input = 1.136-1

24 tooth primary - 30 tooth idler - 24 tooth input = 1.0-1

23 tooth primary - 30 tooth idler - 23 tooth input = 1.0-1

24 tooth primary - 30 tooth idler - 25 tooth input = 1.0416-1

23 tooth primary - 30 tooth idler - 24 tooth input = 1.0434-1

22 tooth primary - 30 tooth idler - 23 tooth input = 1.045-1

23 tooth primary - 30 tooth idler - 25 tooth input = 1.0869-1

22 tooth primary - 30 tooth idler - 24 tooth input = 1.09-1

24 tooth primary - 30 tooth idler - 23 tooth input = 0.958-1

 

the gears will need shimming when swapping

[mini-geek]

A little more complicated than you suggest, you need to remove the wok, flywheel and the flywheel housing (drain the oil, new gasket, clutch oil seal) the drop gears are between the alloy housing and the block/gearbox
 
Minispares sell the following sets -
 
22 tooth primary - 30 tooth idler - 25 tooth input = 1.136-1

24 tooth primary - 30 tooth idler - 24 tooth input = 1.0-1

23 tooth primary - 30 tooth idler - 23 tooth input = 1.0-1

24 tooth primary - 30 tooth idler - 25 tooth input = 1.0416-1

23 tooth primary - 30 tooth idler - 24 tooth input = 1.0434-1

22 tooth primary - 30 tooth idler - 23 tooth input = 1.045-1

23 tooth primary - 30 tooth idler - 25 tooth input = 1.0869-1

22 tooth primary - 30 tooth idler - 24 tooth input = 1.09-1

24 tooth primary - 30 tooth idler - 23 tooth input = 0.958-1
 
the gears will need shimming when swapping

I'm confused them, why would I need to remove the idler and input if I'm keeping them the same?

[Guess-Works.com]

No you don't unless you are changing the input gear...

 

If you change a 24/24 combination to a 24/22 then the overall final drive (in 4th) will be multipled by 24/22 or 1.090909.... which will change your 3.44 to 3.76 approx.

 

if you ran a 24/23 then the overall final drive would be multiplied by 1.043

 

or

 

I could have just pointed you here...

 

http://www.guess-wor.../Tech/ratio.htm

[Guess-Works.com]

One other thing worth mentioning... make sure the primary gear is compatible with the ones you already have... makes a lot of noise and swarf if they arn't