LRP 3 star gearing?

[Rob]

Anyone know what sort of pinion should be with for the old style LRP 3 star brushless motor with stock spur?

[pro4nut]

20-22 was the range i used last year

[hickston]

I dont know what the stock associated spur is (82?), but isnt it

Spur / pinion * internal drive = drive ratio

82 / 20 = 4.1 * 2.43 (xxx-cr it the only one I know) = 9.963 (or 9.9:1)

According to the LRP website manual for x11 (yes I know it's the older motor, but still around 55k rpm), drive ratio for the 5.5t is around 13.0:1 or 14.0:1. On the Losi, that makes a pinion of around 14/15

Youd have to substitute the associated spur and internal drive ratio obviously

[Rob]

Found on LRP site ratio should be 11.0:1 so that makes pinion 19.

[burgie]

i am quite sure mine is the three star motor, and i am running 21 tooth pinion with stock spur gear on an original lrp sphere with reedy motor combo. Baz Weldon used to run his on a 19 pinion and always thermalled it.


that was on a b4 too.

[mark christopher]

Originally Posted by burgie

i am quite sure mine is the three star motor, and i am running 21 tooth pinion with stock spur gear on an original lrp sphere with reedy motor combo. Baz Weldon used to run his on a 19 pinion and always thermalled it.


that was on a b4 too.

wouldnt a bigger gear (higher ratio) be the cause of thermal due to over gearing?

[Chequered Flag Racing]

Nosram 3* on 18/19 with 78 spur indoors @ TRCC with X6 (uses a B4 gearbox internals)

[Rob]

Last year I used a 4 star for a couple of meetings and ran a 17 or 16 pinion, so 19 sounds about right to start off with for 3 star. Will just see how it goes on track.

[burgie]

Originally Posted by mark christopher

wouldnt a bigger gear (higher ratio) be the cause of thermal due to over gearing?

maybe, but mine (on the 21 pinion) doesn't thermal, the LRP with the 19 pinion thermalled. Draw your own conclusions

the gearing i am using came from a suggestion by Doughty on his website, so who am I to say it's wrong?

[mark christopher]

Originally Posted by burgie

maybe, but mine (on the 21 pinion) doesn't thermal, the LRP with the 19 pinion thermalled. Draw your own conclusions

the gearing i am using came from a suggestion by Doughty on his website, so who am I to say it's wrong?

not saying its wrong , just curious as maybe we go the wrong way with gearing wen we have a thermal!

[Oscar]

Maybe its just down to Lead thumb Weldon

[pro4nut]

Originally Posted by mark christopher

not saying its wrong , just curious as maybe we go the wrong way with gearing wen we have a thermal!

I was advised to try gearing up a tooth when i first got my lrp brushless by a couple of the helger drivers.

My 'ASSUMED' reasoning being that you were not making the motor have to rev as high to achieve a speed, the higher the rpm the faster the esc has to switch after all, and as i understand it is the switching that causes the heat build up in the esc. The higher load in the system of higher gearing is less damaging i again assume.

I left a 21T pinion on mine all of last season rain or shine without any problems.