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Old 04-14-2004, 10:48 PM   #1
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how much of a runtime can u get with a stock motor and a 3000mah pack........the last few days i've been running close to 15 minutes on a pack before it really starts to slow down(timed it 3 times).............then it takes another 5 minutes of discharge at 5amps.......my final ratio is 7.9......is that too high........the pack is warm to hot and the motor is warm to cold...depending on how hard i ran it......
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Old 04-14-2004, 11:07 PM   #2
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Lower gearing= low temp and longer run times. Can't give advice without knowing: what car, spur gear, track layout and specific motor. Most gear ratios are designed for a five minute run (race length), but the newer NiHm's give longer times no matter what. I am testing a new Venom 3300 stick pack. My FT TC3 with a 9 turn double= 5 minutes. Same pack in my daughter's (untouched) RTR TC3 (19 turn)= 18 minutes!!! First ever run with the pack lasted 20+ minutes.
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Old 04-15-2004, 07:59 AM   #3
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i've been thinking about going to a larger pinion gear for now and see what happens..........my track is small so i need acceleration not speed.........the gearing right now is 25/78 with a tranny ratio of 2.5333333
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Old 04-15-2004, 09:23 AM   #4
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Quote:
Originally posted by h22ah
i've been thinking about going to a larger pinion gear for now and see what happens..........my track is small so i need acceleration not speed.........the gearing right now is 25/78 with a tranny ratio of 2.5333333
I think for better acceleration you'd have to use smaller pinion instead,.. or bigger spur
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Old 04-15-2004, 09:26 AM   #5
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Larger pinion = taller gearing = LESS acceleration...

If you think better acceleration will help improve your laptime
then you need to try a SMALLER pinion (lower gearing).

Make laptimes your best measure for gearing... go up or down
until your lap times stop getting better, that's the only yardstick.
Any 3000 will be more than enough runtime for a stocker.
It don't matter if your batteries come back half-full as long as
your car is lapping as fast as possible.



You can't do much to a stock motor, but you can change its
brushes & springs. These can make a little difference.
Keep your motor well-maintanined & lubricated always.

There's also always better batteries out there, ones with highest
voltage and lowest IR for the best punch. This can lower laptimes.
Think the 3300s are better cells than 3000s too; if 3300s are what
your competition are using then you might need to join the club.
Not for the runtime but for the other better specs.
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Old 04-15-2004, 10:08 AM   #6
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Quote:
Originally posted by WC
Larger pinion = taller gearing = LESS acceleration...

If you think better acceleration will help improve your laptime
then you need to try a SMALLER pinion (lower gearing).
I'm amazed at how many people say it wrong. A smaller pinion results in a HIGHER gearing, which does result in better acceleration (to a point).

IE: Start with 88 Spur/22 Pinion = 4

Go down to a 21t pinion --> 88/21 = 4.2 so you're "gearing up"

Go up to a 24t pinion --> 88/24 = 3.67 so you're "gearing down"

Yah, I'm anal about it and it's confusing but it's hard to get the right advice when even the good racers get it mixed up and then it gets you mixed up. They'll say "gear up" and mean to put on a larger pinion but it really means to put on a smaller pinion
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Old 04-15-2004, 10:23 AM   #7
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NOPE.

I go by the "stickshift convention".

When you're pulling away from the lights, you use 1st gear... say 10:1.

As you go faster, you change UP your gears.

On the highway you'll be cruising in 4th gear (say 1.2:1) or 5th (say overdrive at 0.8:1).

Makes sense if you can stir a stickshift... or do you have headaches controlling 3 pedals with 2 feet??
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Old 04-15-2004, 10:28 AM   #8
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I go by the top speed at 3/4 the length of the straight method, and the if you can hold your thumb on the motor for 3 seconds before it melts your thumb then its not too hot.
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Old 04-15-2004, 11:18 AM   #9
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So, when I shift from 3rd gear to second gear, I am UP SHIFTING. NO NO NO NO NO. I am DOWN SHIFTING.

Gearing DOWN is going to a smaller pinion, or a LARger SPUR gear. Gearing down makes your gear ration increase, but its called GEARING DOWN.
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Old 04-15-2004, 12:29 PM   #10
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Here's the best way to figure it out. The motor's armature spins at the same RPM no matter what. The more teeth on the pinion, the more surface of the spur it will cover. The smaller the surface of the spur, the more times it will spin in the same turn cycle. Larger pinion + smaller gear= acceleration + excessive motor wear.
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Old 04-15-2004, 01:10 PM   #11
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dam i didn't mean to start an argument.....oh well...........next question changeing the pinion nets more results than changing the spur?????gearing table .........now i just added some numbers for motor rpm so don't rag on me about that.......for every tooth on the spur the speed changes ABOUT .3 mph while every tooth on the pinion changes speed ABOUT .8mph.....so do u always change the pinion or when do u know when to change the spur
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Old 04-15-2004, 04:59 PM   #12
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Quote:
Originally posted by Gutter Ball
I'm amazed at how many people say it wrong. A smaller pinion results in a HIGHER gearing, which does result in better acceleration (to a point).

IE: Start with 88 Spur/22 Pinion = 4

Go down to a 21t pinion --> 88/21 = 4.2 so you're "gearing up"

Go up to a 24t pinion --> 88/24 = 3.67 so you're "gearing down"

Yah, I'm anal about it and it's confusing but it's hard to get the right advice when even the good racers get it mixed up and then it gets you mixed up. They'll say "gear up" and mean to put on a larger pinion but it really means to put on a smaller pinion
Sorry to break it to you dude, but you're the one that's backwards. I've been in many forms of racing and universally, a higher number on your ratio is LOWER gearing. A 7.0 is lower than a 6.5. They're thinking right when they're talking about shifting gears in a car. Go from first gear, say 10.0:1, UPshift to 2nd gear, that's say 8.5:1. 5th or 6th gear, or HIGH gear, is going to be your closest to 1:1. If you gear up, usually you're going to go to a larger pinion, and effectively lowering the gear ratio number (going from a 7.0 to a 6.5 for instance.) You're right that it's confusing.

As far as when to change what gear, that's a debate that's been going on for a long time. Some say that a larger spurgear will create more of a flywheel effect and yeild more top end than the exact same ratio with a smaller spur. I've tried it and to be honest, there may be a difference, but if you so much as touch one dot in the race, you've eaten up all the time you're going to save in that race using a larger spur. So most of the time I change pinion gears because they're easier unless I need to fine tune the gearing and the only what to do that is to go to another size spur.
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Old 04-15-2004, 05:09 PM   #13
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Jon is right. You have it backwards. When you're gearing up, your usually referring to going up in teeth on the pinion. When "gearing" up, your changing the pinion, or spur, but usually not both; at least when you're explaining it to someone. What you are talking about is, "ratio'ing" up, not gearing up.
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Old 04-15-2004, 05:21 PM   #14
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So sounds like... the STICKSHIFT rules!!
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