thank you for your input.

:nod:

That would be a very large sper and pinion might not fit

If you track is as big as aldershot (uk) then u might want 3.2-3.5 which you would be better off with a 66t sper and carry pinions 39-42t
Pinion Fdr on 66t sper
39t 3.38
40t. 3.30
41t. 3.22
42t. 3.14

This is what I ran on my tc6 which internal ratio is also 2.0

Uhh... 64 pitch?

I can no longer find the original website, so I can't take the credit for these, but these tables show what spurs and pinions fit in a TC6 for 48 and 64 pitch:

http://deckjockey.com/tc6/wp-content.../08/gear64.png

http://deckjockey.com/tc6/wp-content.../08/gear48.png

No 48 pitch

If you want 3.67 closest you can get on 64 pitch u need a 67t pinion
And 123 sper

But you would have to try if they are right size to fit

ummm not sure a 123/67 will fit.. but a 92/50 will, and thats 64 pitch.

Thanks Nick... some folks seem to be under the impression that only one combination will yield the FDR desired. :rolleyes:

How bout 226t spur and a 123t pinion? Will that fit? 32 pitch...lol
It's all about the numerical ratios when it comes to FDR but the pitch will determine the actual diameter of the gears, given their tooth count. That's where fitment comes into play. The original suggested gear combo was for 64 pitch not 48 and it was presumed that it was fairly obvious.

I cut some metal yesterday and found a couple miscalculations. I will give it another go Monday Night and hopefully I will have a finished prototype on Tuesday.

:rolleyes: 48pitch is what has always came on all brands i have seen apart from tamiya so with out knowing that how could one tell :rolleyes:
:rolleyes: plus 48pitch 92sper and 50 pinion aso gives you the fdr 3.68 :rolleyes:

Since we are talking ratio's and gears and stuff. What is the general opinion on gearing sizes. For example is it better to run the biggest or smallest spur gear possible then choose the pinion that gives the desired ratio. Or does it matter?

An example would be is there a differnce in running a 102/51 vs. 98/49 vs. 94/47? The ratio of these gears is all the same but will they feel or function differently? As in speed, temp, punch, etc.

hey rich,the largest 48dp pinion i can get to fit is a 43,i can just get a 44t on but i cant get to the motor screws,so how do you get the bigger pinions to fit?

That would be to low I think, what timing are u running on which motor? 41t was as big as I went with a 17.5 thunder power 35 deg timing on the motor and 42t on a 17.5t speed passion mmm with 20 deg timing on the motor

If I run the 44t maybe a ball ended Allen key ?

From what I have been told, the primary difference is the ability to shift the motor location for weight bias and gearing effects on braking leverage. Rotating mass comes into play as well since the pinion typically rotates several times faster than the spur.

No worries... just having a little fun at your expense. :D

I suppose the rule of thumb is: If we are talking about spur gears over 90t, it's likely 64p with regards to touring cars.

Yes, 92 divided by 50 then multiplied by 2 does come out to about 3.67 and you have backed up my example that the math all works out the same regardless of the combination.
That was my point exactly.