What is the best gear ratio for a 6.5 hp clone?

[Aleks976]

What would a good gear ratio be for my 6.5 hp clone? I have a Cent. Clutch, and I know you will say "Get a Torque Converter" but I wanna know for a 14 tooth Clutch. My sprocket is 70 teeth right now So please help

 

[anderkart]

That depends on:

How many inches tall are your rear tires?

Where will you be riding? (hard/flat surfaces only, or maybe off-road and trying to climb hills?)

And finally would you prefer to have a quicker take-off and less top speed, or less acceleration but a higher top speed? (or do you want to compromise somewhere in the middle)

 

[Night rider]

With std 10" dia. kart tires 6:1 is a good over all ratio

 

[Aleks976]

I want a faster top speed, around 70 kmph or faster, because with my gear ratio, i go from 0 - 40 kmph in about 2 seconds, way too much torque. And tires are 11 in. tall and i drive on streets and parking lots

 

[kazkepox]

jesus what kind of kart are you running???

 

[Doc Sprocket]

I very much doubt you're going to like the result if you gear for 70k. Your takeoff'll suck. There's a speed calculator somewhere on this site that will help you select the right ratio to achieve that top speed. Truthfully, and I know you didn't want to hear this... CVT is probably your best bet if you're aiming that high.

 

[Aleks976]

jesus what kind of kart are you running???

A 6.5 hp Honda clone, with a 14 tooth Cent. Clutch and a 72 tooth sprocket.

 

[Doc Sprocket]

Tire diameter?

 

[kazkepox]

i mwan how the heck are you getting to 40mph in 2 seconds with a clone??

 

[Doc Sprocket]

i mwan how the heck are you getting to 40mph in 2 seconds with a clone??

No, man. 40 KILOMETERS- That's 25mph. Re-read his post.

 

[kazkepox]

oooops sorry

 

[redsox985]

Can someone sticky a link to the speed calculator it's referred to as "somewhere on this site" at least twice a week?

 

[Russ2251]

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

 

[Russ2251]

This one is more accurate. No need to sticky. Bookmarks in all browsers work.
http://www.csgnetwork.com/kartpotentialspeedcalc.html

 

[danjwant]

If your currently going 0-40 kph in 2 seconds on 11 wheels, firstly wow, but secondly convert some of that acceleration into top end speed.

At the moment you're riding on a 1:5 gear ratio (14:70) try, 1:4 or maybe even 1:3, however if you're using a centrifugal clutch at that speed and gear ratio I'd be careful, and really consider a torque converter.

Alternatively try a bigger set of wheels, maybe 15 inch. That way you can keep your gear ratio as the bigger wheels will reduce acceleration but increase top speed. Also bigger wheels means a nicer ride.

Consider both, and a torque converter as most centrifugal clutches can't handle that power.