Green plate

Packman88

Member
We have a green plate clone from uncle franks, we ran it yeseday on a banked 1/7 mile , hot laps we turned 4853 on a 16/64. Jumped to a 66 on the rear and actually only turned 4350?? So for the some sr guys next to us said track had slowed down so I went 16/68 and turned 5350. I was told should be 56-5800. Did I just not go big enough on the rear or should I have went smaller on front? ..Or did I go the wrong direction all togetehr
 

alvin l nunley

Premium User
Something strange is going on. Makes no sense; you put on a lower gear and lost a bunch of RPM. You put on a lower gear still and gained a bunch of RPM?? For every tooth you add to the axle, you need to pick up somewhere around a hundred RPM to be going the same speed. You went 4 teeth lower on the rear sprocket, gained 500 RPM, from the 1st to t he last, and picked up 1.5 mph, which should be very close to right.
You could try a 15/64 (about the same as a 16/68) and see if you could match that last RPM.
speed range.jpg
 

flattop1

Dawg 89
Your kart was probably tight . What did the lap times do ?
Rpm is not the do all , lap times tell the real story.
 

Packman88

Member
Did you change tires between ever run


No we was actually on the treaded tires, we have not gotten any maxxis or anything cause we been focused on predator stuff. It did rubber up and I think with the treaded tire we was to tight as someone mentioned up, which makes sense. Just thought maybe it would still turn more, they seemed to jerk us on the start a bit. Just curious if maybe I was doing something wrong
 

racing promotor

Moderator
What air pressures while on the 64, what air while on the 66, and what with the 68 ?
Were there any major handling issues, if so what ?
 

Packman88

Member
What air pressures while on the 64, what air while on the 66, and what with the 68 ?
Were there any major handling issues, if so what ?
What air pressures while on the 64, what air while on the 66, and what with the 68 ?
Were there any major handling issues, if so what ?


16 /64 Hot laps had moisture we was 6 in the rights , and 5 on lefts

16/64. Heat one started to slick off so I dropped to 5.5 rights 4.5 left.


Heat 2 : 16/66 Same air

Feature : Rubber 16/68 back to 6 in rights and 5 on left....He pushed a bit, I'm thinkking it waa a combination of not enough air causing treads to dig worse, and there was like black highway for a groove and he needed to open his entry a bit. Just a learning experience.
 

Big Chris

Member
If your rules allow, you should put a POV camera (go pro or the like) on your son/daughter's helmet. Make sure the steering wheel and his/her feet are in the picture.
See if the rpm issue is the driver. (the one that wears a helmet)
The reason I say this is the data you have shared is counter intuitive.
 

flattop1

Dawg 89
Feature : Rubber 16/68 back to 6 in rights and 5 on left....He pushed a bit, I'm thinkking it waa a combination of not enough air causing treads to dig worse, and there was like black highway for a groove and he needed to open his entry a bit. Just a learning experience.

Notice he says treads if that makes any difference .
 

Bumpy

Member
Why is everybody hung up on RPM ?
10,000RPM with a bad lap time is not the answer.
Lap times are what win races.
I took advice from someone who had won multiple races after we ran 2nd in the heat
at ~5700RPMs and we were close on 1st place. In the main we added some rear teeth
and finished 2nd back 1/4 of straight. But we turned some really good RPMs.
Adjust ratios to get lap times and if your lap times decrease ignore the tach.
After you can't go any faster, work on freeing the kart up, then start over experimenting
on ratios.
 

1fasttiller

Member
Why is everybody hung up on RPM ?
10,000RPM with a bad lap time is not the answer.
Lap times are what win races.
I took advice from someone who had won multiple races after we ran 2nd in the heat
at ~5700RPMs and we were close on 1st place. In the main we added some rear teeth
and finished 2nd back 1/4 of straight. But we turned some really good RPMs.
Adjust ratios to get lap times and if your lap times decrease ignore the tach.
After you can't go any faster, work on freeing the kart up, then start over experimenting
on ratios.
This is solid advice, and so many are hung up on obtaining MAX RPM, why? If the motor is making power down low and has a broad power curve, Why the need to spin it 7000? I recently built a clone for a guy who is usually 30-40lbs over the weight of others in the heavy class. I purposely built this motor to provide maximum torque to get him off the corners. He called me the other night after running it the first time and told me it was the fastest motor he had ever ran but that he couldn't get it to turn over 6600-6700 rpm. I asked him why should it? Gear it correctly and let it pull! RPM's don't make lap times!
 
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