Yokomo 870c with brushless?

[Toasted Coastie]

Is anyone here running there Yoke 870c with a brushless motor? What pinion gear would be best for it? What would be a good set up for this car?

I can't seem to find the right combination motor/pinion with the lipo saddle packs I am running with. I did have a 19t Venom motor with a 28 tooth pinion, but that motor is all done now. Tried to run it with an 18 tooth pinion, and it wouldn't even go. I must have fried the motor the night before.

Tried a 27t HPI motor with the 18 tooth today, and it was just too slow. However, the motor stayed nice and cool.

I want to go brushless, but I don't want to break the friggen bank either (as if I hadn't already on this car).....

[Bugle]

What motor do you want to run?
You won't be able to gear it for a 17.5t unless you can get a spur gear mount for taking standard spur gears, the original spur is too big. Anything 10.5t or faster you should be able to find a ratio with the standard spur.

[Toasted Coastie]

What motor do you want to run?
You won't be able to gear it for a 17.5t unless you can get a spur gear mount for taking standard spur gears, the original spur is too big. Anything 10.5t or faster you should be able to find a ratio with the standard spur.

OK, here come the questions:
Which part is the spur gear? Is it the big white gear the pinion drives? How many teeth are on it?

What turn motor would be the simplest solution?
What size pinion would be right with a 10.5t?

What is a good ratio, and how do you do the math to find it?

I'm looking at either the Associated Eraser: http://www.hobbyetc.com/cgi-bin/item.cgi?part_id=55852

Or the Castle Sidewinder: http://www.hobbyetc.com/cgi-bin/item.cgi?part_id=57100

Thank you,

Ron

[Bugle]

Yeah the big white gear is the spur gear, on mine it had an 81 tooth gear when I got it.
I usually use this as a guide for initial gearing then remove a pinion tooth to be extra safe http://www.teamnovak.com/tech_info/brushless/br_gearing.html
It has an explanation down the bottom on how to calculate the FDR from different spurs and pinions, the internal drive ratio on the Yokomo is 2.33:1. So for a 10.5 i'd start with a 22 pinion assuming you have an 81 spur.

The sidewinder is alright but remember you've gotta buy the castle link on top of that to be able to plug a computer in (extra $20?) or else you're left fine tuning it with flashing lights and tones. The Eraser doesn't have any computer setup capabilities though? The Castle 5700kv should be a bit nuts, faster than a 10.5t, closer to a 6.5 or 7.5

[Toasted Coastie]

Yeah the big white gear is the spur gear, on mine it had an 81 tooth gear when I got it.
I usually use this as a guide for initial gearing then remove a pinion tooth to be extra safe http://www.teamnovak.com/tech_info/brushless/br_gearing.html
It has an explanation down the bottom on how to calculate the FDR from different spurs and pinions, the internal drive ratio on the Yokomo is 2.33:1. So for a 10.5 i'd start with a 22 pinion assuming you have an 81 spur.

The sidewinder is alright but remember you've gotta buy the castle link on top of that to be able to plug a computer in (extra $20?) or else you're left fine tuning it with flashing lights and tones. The Eraser doesn't have any computer setup capabilities though? The Castle 5700kv should be a bit nuts, faster than a 10.5t, closer to a 6.5 or 7.5

Yes, I noticed the stamping on the gear a little while ago, "81T".

I really don't want to get too far into it with programming and such, I think the Eraser would be just fine. I'll probably pick up a pack of pinion gears as well. It's a rainy day here, so it's not like I will run it today, but everything is closed tomorrow....

[Bugle]

Yeah the eraser 13.5t should have enough power for the 870c, will give heaps of run time too

[Toasted Coastie]

Yeah the eraser 13.5t should have enough power for the 870c, will give heaps of run time too

I figured if the car was screaming with a 19t Fireball with a 28t pinion, it will probably go just as fast with the 13.5 and a 20t pinion

[Toasted Coastie]

Yeah the eraser 13.5t should have enough power for the 870c, will give heaps of run time too

I figured if the car was screaming with a 19t Fireball with a 28t pinion, it will probably go just as fast with the 13.5 and a 20t pinion

So I bought the set up, got it all hooked up, and the motor is junk. It would turn half one way and stop, and then get really friggen hot. All the wires got red hot, so I unplugged and let cool. Unplugged the brushless motor and plugged in a brushed one, and it worked great, wires and motor stayed cool.

I'm so friggen pissed right now about this its rediculous. The store won't do anything about it (it was not New Era). So I have to wait until Monday to talk to anyone from Associated, because they are the LRP distributer.

Way to blow my weekend. I should just put this car on ebay and buy a new car at this point. I spend more time waiting for crap then actually playing with my son.

Edited to add: I just figured out that the motor is missing a wire, its missing the hall sensor wire that goes from the back of the motor to the esc. I wonder if that is why it wont turn....

[Bugle]

Yeah it requires the sensor wire, should've come with one? Also remember to connect ABC up in the correct order

[Toasted Coastie]

Yeah it requires the sensor wire, should've come with one? Also remember to connect ABC up in the correct order

Nope, there wasn't one in the package. What a fail. I'll go to New Era tomorrow (they are the only place on a Sunday that is open) and see if they have any. If not, going to be another week wait. However, I did put the 27t in there with a 22t pinion to mess around for a while.

[Bugle]

They should be easy to get, they're a common part to break, they always snap the tiny wires off at the connectors

[Toasted Coastie]

Got it all set. This buggy hauls! Put the Proline Dirt Hawg tires on it and it hooks up nice. It now smokes my son's Rustler. Thank you for all the help!