MR4 BX Help with motor & pinion etc
 

Hi Guys,

I've just purchased an MR4 BX from eBay and I'm after some advice on suitable spur gear & pinion setups.

I'm looking to buy an LRP 4.5 brushless motor with the Sphere Comp ESC. However, I'm unsure what I need to purchase in terms of spur gear & pinion to work with the LRP motor & ESC?

Please can you help me with what I need?

Also, do I need to worry about a fan & heatsync to keep the motor cool?

Thanks in advance for any help or advice you can share with me.

Kind Regards,

Greg.

Hi Greg,

Hope you enjoy the Yoke i did :)
The standard spur on the car is fine and with regard pinion you should be looking around 15-18.
I ran the Novak brushless in the car with the 5.5 i can honestly say i would have never put the 4.5 in.
By the way the car will be with you tomorrow.

Nice one!!!

I didn't realise you lived on here too ;-)

Looking forward to getting it and I'll have a play around with the different pinions as you suggest.

So I take it I don't need to alter the existing spur?

Thanks,

G.

You got to have something to look at on the tintin net.
The spur thats on the car is fine, but it could do with changing now as a stone got caught in there and marked it. There is one in there.

Hi,

I use 84/15 with my Vector X11 6.5. I think you will have gear mesh problems using a smaller pinion with this 84 spur gear. Change it to a 87 spur gear and start with a 14 tooth pinion with the 4.5. Then check the temperature. I think a 15 tooth pinion will be too big but you may have a try.

A 4.5 motor will be too powerful for an offroad car I think. You may also have ESC temperature issues with this motor if you don't use a fan. The body of the Yok is tight and needs to be cut if you decide to use a fan.
If I were you I would rather buy a 5.5 or even a 6.5.

I hope this helps.

Gil

i have a novak 4.5 in mine, ran it last weekend for the first time. had it geared 15/84 no heat issues. car was a bit loose so i have flipped the rear ball studs.