Brushless gearing advice

[c0sie]

I understand the theory behind how to gear a brushed motor optimally, but ever since going over to BL ive had issues trying to understand the theory behind gearing my brushless systems.

For example...if you undergear a brushless significantly (say by 3 or 4 teeth) what would that do to acceleration, top speed and temperatures?

The same question for over gearing.

How do you figure out the optimum gearing to run on a brushless?

Thanks in advance

[blue_pinky]

Ello matey,

Don't know any deep technical/scientific ways, but the ways I've been doing it...

Firstly, make them use their full rev range as best you can, so be geared so that they hit about top rev's at the fastest point(s) on a circuit.

Too much running at max revs will over heat them, too much running them slowly will overheat them...get it balanced so it's essentially using it's full rev range on the track as best you can...you certainly know when you've hit the sweet spot on the motor, it runs at it's most efficient at a particular point...I just don't know where it is in the rev range!!!

Secondly, fine tune via temp measurements as they have an "ideal" apparently...not sure off hand what the magic number is but I'd guess it'd be easy to find on here somewhere, or on the instructions for your motor.

Dave has a sensor with him usually....and he'll happily do quick check for you after a race!

[c0sie]

Cheers Andy

So, basically, its the same theory as brushed then? Gear it so that its revving out at the fastest point on the track?

Sorted

[blue_pinky]

I've never actually used a brushed motor in anger......so can't make a comparison!!! Been on brushless since I started racing.

Had one in a TC4 as it came with one in it when I bought it second hand...but not really used it much as I got into buggies at the same time...never really got into TC's at all so it's gathering dust currently....maybe I should stick it in the for sale section!

[c0sie]

Am I right to think that Andy has hit the nail on the head with his reply? Seeing as no one else has posted any kind of reply for me?

[blue_pinky]

I'll second that request! I only know what I've done up to now, only evidence I have that it works is that my motors are all still alive and kicking!

[peetbee]

Not sure how much longer that motor's going to last in your thundershot unless you sort a different pinion though!

[blue_pinky]

lol...very true...but in my defence I'm not exactly spoilt for choice in that car though!!!

Although I have now managed to get a 14t 32dp pinion off ebay...1 tooth smaller than what's in it currently, and although it's been pretty hot, it is still alive!