Jackshaft gearing. Is my plan gonna work?

[getting kart smart]

I am going to redesign my current setup which has no torque. I want to have a top speed of about 25 to 30 mph. I have a 17 tooth clutch sprocket and 18 inch tires. It will be powered by an 8 horse briggs. This is all new to the kart. I want to put a 40 tooth jackshaft sprocket coming from my clutch and and a 12 tooth jackshaft sprocket to my 60 tooth axle sprocket. This should give me around a 12 to 1 ratio. I know the big tires are gonna be hard to push. It works in my minds eye but math has never been my strong suit. Anybody got any suggestions or comments or good sites to figure ratio with jackshafts in mind?

 

[landuse]

I am going to redesign my current setup which has no torque. I want to have a top speed of about 25 to 30 mph. I have a 17 tooth clutch sprocket and 18 inch tires. It will be powered by an 8 horse briggs. This is all new to the kart. I want to put a 40 tooth jackshaft sprocket coming from my clutch and and a 12 tooth jackshaft sprocket to my 60 tooth axle sprocket. This should give me around a 12 to 1 ratio. I know the big tires are gonna be hard to push. It works in my minds eye but math has never been my strong suit. Anybody got any suggestions or comments or good sites to figure ratio with jackshafts in mind?

Using the numbers that you have provided, I get (40/17)*(60/12) = 11.75:1.

This should give you loads of torque, but your speed will be compromised. I have tried to gogle a jackshaft speed calculator, but have had trouble finding one that I can actually use, so I am not too sure what speed you are going to get.

 

[gvfc2]

could use the speed calc on this site just put in 12 to 1 and it will give you your speed

12:1 will give you 16mph could use a 8 or 9:1 still give enough torque to move it. also could always remove gov if you want more speed

 

[landuse]

could use the speed calc on this site just put in 12 to 1 and it will give you your speed

12:1 will give you 16mph could use a 8 or 9:1 still give enough torque to move it. also could always remove gov if you want more speed

Thanks gvfc2. Why didn't I think of that. LOL. I was trying to put the primary ratio and then secondary ratio in. Stupid me

 

[gvfc2]

haha lol learn something new. but i heard it awhile ago. you can also do the same thing with pulleys the measure in inches

 

[landuse]

haha lol learn something new. but i heard it awhile ago. you can also do the same thing with pulleys the measure in inches

I know the pulley calculation. You just use diameter instead of tooth count

 

[OzFab]

I have tried to gogle a jackshaft speed calculator, but have had trouble finding one that I can actually use

This will give you the jackshaft final ratio, then, as previously suggested, use our speed calculator to find top speed

 

[landuse]

This will give you the jackshaft final ratio, then, as previously suggested, use our speed calculator to find top speed

Thanks Fabroman, but I have that calculator. It was the speed calculation I was having a problem with