Gearing help for stock box predator on 1/5 mile dirt

Codyh27

Member
Hey guys im fairly new to kart racing this yeat been learning and running my local track its like a bull rink ran 5 races so far there finished no less than 3rd but were going to hunterstown speedway in pa on sat and trying to figure out the gearing ive never been there its 1/5 mile dirt real fast track the class im racing in is stock no mods at all just trying to get some gearing help maybe what i should start with or just some direction the class is 375 but im over just about 25 pounds any help would be appreciated thanks yall
 

Codyh27

Member
Im not sure the size they really dont say but its small and i been hitting around 4750 rpm heres a pic idk if you can judge off the pic
 

Codyh27

Member
Here the track highview speedway
 

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alvin l nunley

Premium User
Take a look at this. Notice how much RPM you have to gain to go the same speed with a similar ratio. 16, 17, 18 apply to your situation. One tooth on the driver requires 4 teeth on the driven. Approximately.

Recently I've been thinking; maybe we need a smaller axle sprocket holder. We could run smaller gears and shorter chains, that might be good. Just speculating.
mph_rpm_gear ratio 1.jpg
 

ohv60racr

Member
Hey guys im fairly new to kart racing this yeat been learning and running my local track its like a bull rink ran 5 races so far there finished no less than 3rd but were going to hunterstown speedway in pa on sat and trying to figure out the gearing ive never been there its 1/5 mile dirt real fast track the class im racing in is stock no mods at all just trying to get some gearing help maybe what i should start with or just some direction the class is 375 but im over just about 25 pounds any help would be appreciated thanks yall
Predator ?
 
Take a look at this. Notice how much RPM you have to gain to go the same speed with a similar ratio. 16, 17, 18 apply to your situation. One tooth on the driver requires 4 teeth on the driven. Approximately.

Recently I've been thinking; maybe we need a smaller axle sprocket holder. We could run smaller gears and shorter chains, that might be good. Just speculating.View attachment 10643

Al, this dont really apply in the real world with differing motors.
Example, Possum Kingdom, Predators must use a 21-54 gear for a 2.57 ratio while the clones are on 18-60 for a 3.33 ratio. According to your chart the Predator would be faster than clones when they are actually about a second slower.
Predators are a supposed stock out of box motor, clones are fully built. Predators turn 5000 RPM, clones turn 6800 RPM.
 

Danny Ray davis

New member
I'm wondering if somebody could give me some close information I'm fixing to run and start running it's a quarter mile track dirt what do I only have a 16 driver for the front what would be a good rear gear
 

racing promotor

Moderator
I'm wondering if somebody could give me some close information I'm fixing to run and start running it's a quarter mile track dirt what do I only have a 16 driver for the front what would be a good rear gear
You would need the mini gears for the rear for a 16 driver somewhere around a 44 rear, for regular gears I'd try a 19/56 to start, as mentioned that's if indeed it's a quarter mile or real close 1320 lf, and even if that IF it grips up real good the 56 rear is probably little much.
 
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