Gear Ratio Effects 4.5:1 vs 3.86:1, Side-by-Side Video

EpsilonZero

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I realized that I had videos from about the same spot when testing out different gear combos. Here is a side-by-side video of 4.5:1 vs 3.86:1 and they are surprisingly close. I think the 3.86:1 just eats more amperage in general, though I don't know why that isn't translating into serious acceleration differences. Anyone have an idea?

I am going to look at putting a 4:83:1 video up against these, but I think I may only have 360 videos of that combo so I'll have to figure out the editing. I do know that the 4:83:1's acceleration was enough to overshoot to the 6000 rpm range and required me to set max rpm to about 5200.

 

Functional Artist

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Nice work & thanks for sharing :thumbsup:
...but, the motor to axle's gear ratio is only 1/2 of the equation

I've found that the driven sprocket's diameter vs. the rear tire's diameter, are just as important to both the motor & the kart's performance :cool:
...so, you have to include the tire size with the gear ratio, to really document/evaluate the situation ;)
 

EpsilonZero

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The tires are 13x5.00-6. Their OD is a little over 12" and were used on both runs, so they are a constant. Thinking about it, it seems like the big issues with the comparison are: starting at slightly different locations, using a GPS speedo with 1-sec intervals, and having different max RPM settings (can't even time by max engine pitch). I probably just need to do a better job at keeping the variables the same (I just happened to have similar footage to compare). Really, if the differences are fractions of a second, this method is not going to be very reliable.
 
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