First time electric go kart build gearing problems

[benhardiman43]

hi I want to build a 36v electric go kart with 2 x 800w motors and im very confused about gearing. Do I need a gear reduction units or some sort of gearing on the motors or will I be ok with just a normal sprocket on the axle.

The motors spin at 2800rpm it has a #25 11 tooth chain sprocket on the motor so what size sprocket would I need to put on axle.

I have a speed controller with all the appropriate connections on. I want the go cart to be as fast as possible any tips or advice on how to build this machine??

thanks in advance

Ben

 

[cboy]

what size are the tires?

http://www.diygokarts.com/speed-calculator.html

 

[benhardiman43]

Hi they are 12"

Thanks Ben y

 

[benhardiman43]

If I have a 60 tooth sprocket on the axle would that work and would I be able to pull straight off from standing in the kart .

I've seen a lot of people mention gear reduction units saying that the motor spins too fast for the kart even if you reduce it so its spinning at 500rpm it's really confused me

 

[cboy]

use the calculator i posted above

i have 11/72 on my kart with 11" tires.
i would have gone up to 11/80 if i could have found a sprocket that big for more torque.

 

[alannasar]

Proper gearing fro electric go-kart

To review, you have a total of 1.5kw @ 2800 RPM with 11t on the motor and 12" tires. You need to choose an axle sprocket. Using the calculator mentioned above, a 60t sprocket will get you 18 mph. a 50t - 22mph, 40t - 27mph. As your gear ratio gets higher your theoretical top speed gets higher but at the expense of acceleration and load carrying capacity. You could also overvolt the motors with 48v to get more top speed as the motors will spin faster. This will allow you to use a lower ratio and get good speed and good acceleration.

Just for comparison, my go-kart has a 1000w 3000rpm motor with 10t on the motor, 60t on axle, and 14" tires. It goes about 20 mph but takes a while to get up to that speed. Your kart should be capable of about 25-30 mph depending on weight and resistance and gearing. More if you overvolt.
Link to my project