Questions about ratios

[rdhdfmn]

So I have a question about the correct ratio for my go cart. I read a post about 6.6:1 is a good ratio to go by. Does that apply to all engines and all carts? So for my build I have a yerf dog( not sure the model) with a 60 tooth sprocket on a live axle (both wheels turn when the sprocket turns). I have 18 inch tires on it. I’m building it for me and my grandsons, I’m 265 and they are still young but I want to be able to ride it with them when they get older. I have a Honda GX340 I’m putting on it. From what I have been told I’m going to put a 40 series torque converter on it. Thanks

 

[kevbo22]

with the 40 series you're going to use it will be fine, yes.

 

[landuse]

You can then still use the 60T sprocket you have and maybe go for an 8 or 9 sprocket on the TC. A 10 should work too, but smaller gives you more torque. You tyres are on the large side, so I would go with the smallest TC sprocket you can get. With grandkids its not going to be about the speed

 

[JTSpeedDemon]

...With grandkids its not going to be about the speed

They will enjoy it more if it does burnouts, donuts, and wheelies.

 

[landuse]

They will enjoy it more if it does burnouts, donuts, and wheelies.

Thats what I mean To get all of those things you are going to have to gear lower (doing the things I mentioned above). Speed might be scary for little ones, but burnouts and "push your head into the seat" acceleration is probably what they are going to enjoy

 

[rdhdfmn]

Thanks for the help guys. Yes, we um I mean they need to do burnouts. So how low would you go?

 

[Tpdingo]

Thanks for the help guys. Yes, we um I mean they need to do burnouts. So how low would you go?

Well there is a point where the wheels have so much torque but they aren't spinning fast enough to do much.

For burnouts.....well even a 4:1 ratio would work if you put water on the ground . Really if you want to have fun sliding and drifting and what-not, put some water on a driveway and go to town. Its worth it.

For flat ground drifting and meaty 18" tires and a combined weight north of 450lbs....well your talking probably 8-9:1 ratio with a TAV. That gives a theoretical 450ft-lbs of torque at the rear wheels...which should break them loose. I know my kart has about 100ft-lbs at the rear wheels and it will spin them on driveway and smooth pavement but not concrete...with a total weight around 230lbs. But also consider....do you want to spin the wheels EVERY time you floor it? And you'll go down to 22mph max speed with the governor.