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Old 01-04-2015 | 02:37 PM
  #46  
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Dr_T
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Originally Posted by 0verkill
What kind of gearing do you think is appropriate with no fan? I only have a 23T pinion at the moment.

Diff Ratio - 4.44
Spur - 44T
Motor KV - 1440 (or it could be closer to 1740 based on your findings)
Tire Diameter - 5.85"
Battery - 6S
Alright, so assuming 1440kv (did you check it yet with your ESC?), your gearing gets you, coincidentally, exactly the same no-load wheel speed as xmods 22T pinion set-up: 66 mph. There are a couple of differences, wheel weight being the most important one I think (yours are heavier, so higher load during acceleration), but his tires were ballooning and yours won't, meaning, assuming all things equal, actual top-speed load on yours will be smaller. Xmod ran that set-up fine without a fan, so if your motor does not turn out to be a much higher kv, you should be good with no fan.

Personally, I would throw on a fan though, just gives you some more breathing room. It's cool to see how the Tekno mount seems to accomodate much bigger pinions. Your 23T pinion seems only little over half of the available "sliding space". With fan, I unknowingly (thought kv was lower, you know the story) ran 79 mph gearing on ballooning Badlands without heat issues. Was a bit hard to get it to full throttle without taking-off though . I'm working on trying some higher gearing for some on-road fun now, but when I get my GT2 up and running I'll probably gear the 8T back to ~70mph for off-road use with fishlined Badlands and call it a day. My skills seem to be lacking to go much faster off-road .

Finally I thought I'd throw in a pic for the "ballooning is good for handling" discussion... This is what ballooning Badlands look like on a fun truggy (yes, those exist ) at 76 mph no-load gearing, center diff is no light 10k cSt racer diff with massive front unloading, but filled with 2.000.000 cSt fluid, so rears look very similar, if not identical...



Personally, I'm not a fan of taping either; for one I suck at gluing tires and in addition I don't like the weight it adds. I'd probably also do such a poor job it would add massive imbalance, which would take even more weight to get rid of. That's why I fishlined mine, works for me and keeps the tire nicely in shape so it actually can keep some surface contact area, and thus traction:

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