proper gear ratio 4 top end & low end?

[spudkilla224]

Hello everyone I had the idea of adapting a centrigugal clutch to accept different sprocket sizes, which would allow me to bolt on any tooth sprocket I desire. But which would be the best choice for enough low end torque without struggling to get up to speed and to have a top end of 45mph?

The sprocket on my live axle is a 48 tooth #40 sprocket, but i want to have a top speed of 40-45mph.

here are the sprockets im eyeballing a 14 tooth 1 which will get me up to 37mph, a 15 tooth which will go 40mph, and a 16 tooth which will gear it up 2 43mph.

I'd like to use the 15 tooth sprocket to be able to do 40mph. also the engine the clutch will be attached to is a 5.5 hp honda clone with the govenor still attached.

so basically would the 15 tooth sprocket work enough to to move a 140lb person, with enough torque to start off fast and have a decent top end?

 

[mike75925]

i would say no. it would seem to me, a slow start(maybe needing a push off) with decent top.

 

[spudkilla224]

ok, how about the 14 tooth, would that be better?

 

[TurtleMann14]

like he said, that's to big of a gap, you would need a transmission of sorts for that range

from what i have experienced 5hp is happy with 25mph differences with a cvt

 

[Kaptain Krunch]

tire Diameter? with a governed engine i wouldnt try for more than 30mph.

 

[spudkilla224]

sorry there 12" diameter tires. just wondering why wouldn't i wanna go faster than 30mph with a governed engine?

 

[mike75925]

it would be better, probably to run a larger wheel/axle sprocket. 60 tooth is pretty good, with a 10 clutch. use one of the gear calculators to see what your top speed will be with different ratios. to be honest, i doubt you will get the performance you are looking for without modifying the engine. the bigger the difference in ratio (6:1, 7:1 etc) the better take off. the smaller the faster you will go(4:1, 3:1 etc). problem is, you would have to make a 2 or 3 speed tranny ,most likely, to get what you want.


http://www.smartkartparts.com/Speed_Calculator.html

 

[Kaptain Krunch]

Too much stress on your centrifugal clutch. Unless you are doing strictly flat asphalt with not much stop and go, your clutch will be getting very hot and takeoff will suffer.

I would go for a 12t clutch, putting you at 32mph.

 

[spudkilla224]

ok i will use the 12 tooth clutch. thanxs 4 the imput everyone.

 

[1992suburban]

i would run a 6:1 ratio with a 12" tire....
I run a 5:1 with an 11" but I am livin large.. @ 250lbs
so if your a lil fella 5:1-6:1 would give GREAT all around performance

 

[bknights]

my first post

i run a 6.66 gear ratio
16 in tires #41 60T and 9T sprocket with a comet 30 series
and gotten up to 38mph with a stock FH 6.5 clone on the street

 

[anderkart]

Hello everyone I had the idea of adapting a centrigugal clutch to accept different sprocket sizes

Cool! lots of exspencive race clutches have replaceable drivers but I've never seen anyone mod a fixed-gear model. Post some pics when you get-er-done

 

[Kaptain Krunch]

Cool! lots of exspencive race clutches have replaceable drivers but I've never seen anyone mod a fixed-gear model. Post some pics when you get-er-done

My comet clutch (looks like a max torque) has interchangeable sprockets. Other than that it was a very crappy clutch though haha.