final drive Ratios for B4
 

Can anyone help..I am struggling to grasp the whole drive ratio malarky. I have just got a xcelerion Sensored 6.5T. In the instructions the FDR is 10.8 for a 2wd buggy. according to instructions this is calculated by divinding spur by pinion then multiliny by internal car ratio (2.6 on a b4. Working backwards an 81t spur equates to a 19t pinion.
Is this right?
How close to the instructions should i go- any scope for higher teeth pinions.
What are you guys running with your6.5T brushless?:eh?:

is the rotor in the motor bonded or sintered?
I run currently run a 5.5L sintered rotor in my X6 (conversion of a B4) with a 20t pinion/81t spur i'd play around with 20/21/22t pinion on a 81t spur with a 6.5 sensored motor, just check the temperature of the motor after each run and if you can't touch it with your finger for a fair few seconds without it burning you then it's geared too high so drop down a tooth or two if needed, hope this helps
Mike.

Here's a b4 gear chart

http://www.rc10b4.com/images/driveRatiosMini.gif

So you'd want to be running 20 on a 81t spur to get close the recommended overall ratio.

MiCk B. :-)

thanks
 

makes sense now- cheers

Do spur times transmission ratio divided by the pinion. That is the way I have always done it.

Peace Aaron(W-W)

[quote=Mike Hudson;131047]is the rotor in the motor bonded or sintered?
I run currently run a 5.5L sintered rotor in my X6 [quote]

Yes but the x6 has an extra idler gear compared to the B4 so im sure that will change the internal ratio?

no ben you can add 600 iddler gears of any size and it wont effect the internal ratio.

A

Can you explain to me why please ashley :confused:

Only the gears on the layshaft and diff gear are used when calculating internal ration the idler gear i just for joining the gears together and determaning the way the wheels and motor spin. The idler gear with 90 teeth or 9 teeth wouldnt make a diffrence to the internal ration as the iddler gear just transferres the power. Its very difficult to exsplain.

A

OMG Ashley is right once again.??
the idler gear is just like a transfer gear Ben, and as its the same size as the first theres no reduction or increase it just turns the gear in another direction,

owww ok thanks :D ahhh you learn something new every day:D