Box Stock

Red plate gear?

Asking because when you first started this thread you were on a 12/69 turning 5200 with green plate at the now confirmed 11th mile, you have now went to a 13/69 same as 12/65 with everything else staying the same that's 4 teeth change still 5200 rpm, that tells me you were gear bound and most likely still are, pointing this out so you don't think tweaking set up, tires, driver, is the only way to gain rpm because your still off on gearing.
 
racing promotor said:
Asking because when you first started this thread you were on a 12/69 turning 5200 with green plate at the now confirmed 11th mile, you have now went to a 13/69 same as 12/65 with everything else staying the same that's 4 teeth change still 5200 rpm, that tells me you were gear bound and most likely still are, pointing this out so you don't think tweaking set up, tires, driver, is the only way to gain rpm because your still off on gearing.
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On the (12/69) 5200-5400 average, it maxed around 5600 with a drop of 800. On the (13/69) it ran 4800-5000 average, maxing at 5252 with 1000 drop...

However, the kart looked faster. And sounded better.
 
racing promotor said:
Asking because when you first started this thread you were on a 12/69 turning 5200 with green plate at the now confirmed 11th mile, you have now went to a 13/69 same as 12/65 with everything else staying the same
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Actually, 13/70 would get you closer to the same gear. That 4 tooth difference is not consistent across all ratios, the smaller the gear set, the bigger the difference.
 
alvin l nunley said:
Actually, 13/70 would get you closer to the same gear. That 4 tooth difference is not consistent across all ratios, the smaller the gear set, the bigger the difference
alvin l nunley said:
Actually, 13/70 would get you closer to the same gear. That 4 tooth difference is not consistent across all ratios, the smaller the gear set, the bigger the difference.
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Yes correct on paper but that never works out 100 % on dirt track, point still being he's gear bound.
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Call me stupid, but I don't understand the term "gear bound". If you went from a 12/65 to a 13/69, a higher gear ratio, would the term "gear bound" still apply? How do you eliminate "gear bound"? Do you go up or down on the ratio? I really don't know, that's why I'm asking.
 
alvin l nunley said:
Call me stupid, but I don't understand the term "gear bound". If you went from a 12/65 to a 13/69, a higher gear ratio, would the term "gear bound" still apply? How do you eliminate "gear bound"? Do you go up or down on the ratio? I really don't know, that's why I ask.
Provided the 12/65 was correct then NO going to a 13/69 would not be gear bound, he started with a 12/69 I just pointed out the 13/69 was same as 12/65 to show 4 teeth change still turned same rpm. Gear bound is when gearing would equal way more rpm than motor will turn, then to magnify the problem it usually gives false tach readings making it more of a guessing game, I've had guy's pull 6 teeth and gain rpms. That's gear bound.
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I bet when he was on the 12/69 if motor would turn it and tach would of given an accurate reading it would of been like
6200 plus, when he's only looking for 5400.
 
alvin l nunley said:
Call me stupid, but I don't understand the term "gear bound". If you went from a 12/65 to a 13/69, a higher gear ratio, would the term "gear bound" still apply? How do you eliminate "gear bound"? Do you go up or down on the ratio? I really don't know, that's why I'm asking.
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Im obviously no expert but I think about it like this....Take your passenger car or truck on the highway and leave it in first gear....rpms are there but speed is reduced drastically. Basically the gear is restricting the kart from full speed, or desired speed. I would also bet that this can be on both extremes of the gear. Too short and it cant overcome the torque needed to gain speed, to tall and it runs rpms to high before reaching full speed.
 
racing promotor said:
I bet when he was on the 12/69 if motor would turn it and tach would of given an accurate reading it would of been like
6200 plus, when he's only looking for 5400.
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Again thanks for the help. After thinking about it more, I've realized my mistake... My oldest son raced this exact kart 2 years ago. We ran a 12-67 gear then, and he would lap the field twice after he got comfortable in the kart. Rpms ran around 6000 peak. Back then we were still gear bound, but I saw no need to change a gear not knowing what I know now. When we moved my other son into the kart we struggled to find speed. More than likely it was because he was a new driver and still had some learning to do. So I changed the gear chasing the rpm instead of looking at other causes. However, It did train him to keep the throttle down, and keep momentum up. After the change to the 13-69 his laps looked way smoother and he was much faster.
 
Lucky_7 said:
Again thanks for the help. After thinking about it more, I've realized my mistake... My oldest son raced this exact kart 2 years ago. We ran a 12-67 gear then, and he would lap the field twice after he got comfortable in the kart. Rpms ran around 6000 peak. Back then we were still gear bound, but I saw no need to change a gear not knowing what I know now. When we moved my other son into the kart we struggled to find speed. More than likely it was because he was a new driver and still had some learning to do. So I changed the gear chasing the rpm instead of looking at other causes. However, It did train him to keep the throttle down, and keep momentum up. After the change to the 13-69 his laps looked way smoother and he was much faster.
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To be clear I'm only pointing this out first so others chasing rpm realize what's up, and as your son progress your aware you are leaving speed on the table.
 
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