Where to start with gearing

Ash9m

New member
My 8 y.o. daughter will be running a jr champ (295# scaled to percentages) this year with a green plate little pipe clone. She ran a predator last year for a few races and did great. We are running a 1/5 mile dirt in PA. Pinks and blues. engine builder wants it to turn 5400 - 5700. Running a flame clutch. Just wondering where to start with gearing and where the clutch should come in at. Thank you.
 

alvin l nunley

Premium User
Set the clutch to peak torque RPM. Torque X RPM / 5252.1 = HP. Peak torque at the axle means peak HP at the axle.
Measure across the infield. Measurre the width of the track. Stagger can be calculated. Maybe n ot exactly but very close.

Gearing is a little harder. Best to ask around.

A bathroom scale between the front of the Kart and a strong wall is a good way to determine peak torque RPM.
 

Skidude

Member
If you are running the same track, run the same axle sprocket you did with the Predator and drop three teeth on the clutch. That should be a good place to start. That is calculated as 2 MPH faster and 1100 more RPM than the Predator.
 

racing promotor

Moderator
If you are running the same track, run the same axle sprocket you did with the Predator and drop three teeth on the clutch. That should be a good place to start. That is calculated as 2 MPH faster and 1100 more RPM than the Predator.
Maybe if he was running Sr Clone it might be closer, BUT he's asking for Green plate clone small pipe only to turn 5400 rpm to 5700 rpm, If comparing to the predator gearing only, keeping it the same would be much closer than dropping 3 teeth off the front, that's provided he was using the correct gearing in predator class to start with .
 

racing promotor

Moderator
They just put new clay down so it's gonna be a test for everyone, but for regular Sat night show and being a newer driver to that class a 16/57 to start should get you close, once your maximizing momentum 100 % you should be best on a 17 driver, If you run any of the series day races you'll be on a 17 driver for sure, Fresh Maxxis 120 cc Internal wiped with a medium should get you real close on tires 1 1/4 " rear stagger. by the way last season for adult predator the guy's up front on Sat nights were 17/54, 18/58, 19/63 all made it to winners circle, I don't know what gearing the kids predator was on last year but doubt there were many using predators.

Good Luck !!
 
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