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Spurs and Pinions

Spurs and Pinions

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Old 04-17-2006, 10:04 AM
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Default Spurs and Pinions

I'm trying to be quicker off the line (faster acceleration) and I'm pondering a few things. I'm currently running an 87 spur 26 pinion. That's pretty middle-of-the-road correct? I have a 69 spur on the side, and I'm debating what pinion to match it with. The 26 pinion doesn't meet with the 69 spur so I need a larger (in size) pinion. What would that be? Would a 30pinion work?

Looking at gearchart.com, a 30 pinion would be a 4.90 whereas a 28 would be a 5.25.

If I am reading this correct, the 30 pinion would be faster acceleration. I would tend to naturally think that the larger the pinion the less acceleration. Is a 30 pinion larger (in size) than a 26?

Man am I getting confused!


edit: thanks to you guys I'm just happy to have this thing running! Went racing with a friend who has a TL-01 chassis and my RS4 Rally was just as fast even though he had a 10turn less motor (me: 27. him: 17). I know a fair amount about setting up a car, but this rc stuff is making me wonder!
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Old 04-17-2006, 10:21 AM
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Which Speed Control do you have? The reason I'm asking, is a number of them have a feature, that gives you extra punch at the start. Example, with a LRP Speedo, you can hold the brake for 5 seconds, before the start of the race, and this will give you a little extra punch for the start.
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Old 04-17-2006, 10:46 AM
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Associated A.I. Automatic Pro Reverse ESC
Holding the brake would just send me into reverse. :\
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Old 04-17-2006, 11:02 AM
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One thing I failed to think about, was the motor RPM. I don't know it, but I think it's ~20000.

Ok, through some more researching, two things I found that contradict my thoughts.
smaller the pinion will give you more torque, the smaller the spur the more speed.
So let me see here if I get it. Gearing up, smaller spur/larger pinion = more top end speed. Gearing down, larger spur/smaller pinion = more low end torq. Larger tracks with long straight sections, gear up. Smaller tracks shorter straight sections gear down !?! All of this within the limitations of the motor, esc, and batteries of course.

Last edited by kyohpi; 04-17-2006 at 11:15 AM.
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Old 04-17-2006, 06:09 PM
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If u want more acceleration bigger spur or smaller pinion. The ratio u calculated was the Final drive ratio (FDR) so with the 30 tooth pinion for every 4.9 turns of the motor the wheels turn once. but for the 28 it's 5.25 so less top speed for the 28 but quicker acceleration.
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Old 04-20-2006, 09:00 AM
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is there any special rules to match pinion and spur or i can mix up any pinion and spur?
so far i only use pinion/spur that came with the kit.
thanks
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Old 04-20-2006, 09:15 AM
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Originally Posted by ickvanovs
is there any special rules to match pinion and spur or i can mix up any pinion and spur?
so far i only use pinion/spur that came with the kit.
thanks
as long as they are the same pitch you can use any spur with any pinion..
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