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Jacques.Eloff

Question on Brushless Power Setups, Gear Ratios, etc.

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Hi, first time poster here, mainly an RC flyer but enjoying the nostalgia of Tamiya with my daughter! I have done quite a bit of searching on this issue but still a bit confused.

I purchased a Comical Grasshopper (WR-02) and I have put in some upgrades, including a 10.5T Tamiya brushless motor, which gives it a noticeable improvement in speed/acceleration. However, I am concerned I may be stressing the gearbox so I changed the pinion gear from 18T to 20T. My questions are:

  1. Is that the right way to go (ie. bigger pinion)? I assume so, as this will result in less leverage/force on the gears when applying power/accelerating?
  2. Tamiya’s guideline for using 10.5T on a  buggy is that the gear ratio should be between 8.9 and 11.7. How is this calculated? According to the manual for WR-02CB (page 18) 18T pinion = 18.3:1 ratio  and 20T pinion = 16.5:1 ratio, which are both much higher ratios than the guidelines??
  3. Am I sitting on a time bomb with my 10.5T setup? From my RC aircraft background I am much more familiar with KV rating than turns. Tamiya 10.5T is 3370KV and I have seen recommendations for a range of brushless motors on WR-02 which are well above 3000KV which makes me think I am OK, but maybe I am misled? (example - see this link for Wild Willy recommendations: https://www.tamiyaclub.com/forum/index.php?/topic/83734-wild-willy-2-wr02-brushless-motor-esc-advice-needed/&ct=1619359808)

Finally, just to note that I have installed the ESC fan and also checked the motor temp after heavy running and both ESC and motor remain cool.

Appreciate any advice.

Thanks!

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The comical releases of tamiya are meant to wheelie.

 

thats why the high FDR (final drive ratio)

I did run my lunchbox on 19T pinion with a 4300kv motor and 3s. Nothing happened

I am sure you are good with this and dont need to take anymore precautions 

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Mild gearing is very safe. To be truly fast, that motor wants the suggested gear ratio; your ratio will give you decent speed and cool, reliable operation. 

I use a much hotter 10.5 on my G6-01 and it's been perfect.

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I think you are way over thinking this. The WR-02 gearbox is a tough old boot. I've got a 10.5t in my Wild Willy and it's ace. It wheelies on demand like it should. Have fun with it and don't worry about gear ratios etc... not on this chassis any way :D

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