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Old 04-28-2009, 02:08 PM   #1
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Default Gearing Correctly

I think this topic will help alot of newcomers. When many people gear a car, they dont really know what to look for. Do they look for how much the tires spin when coming off the line, or how hot the motor is when the car comes off the track. So please give your opinion of what you look for when gearing your car for the track.
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Old 04-28-2009, 03:21 PM   #2
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I always do it by the motor temp

If I can hold the motor for more than 3 seconds before my hand starts to cook then it's ok in my book..

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Old 04-28-2009, 03:42 PM   #3
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For me, gearing choice is all about the best lap times over the duration of a run, with temperature checks to make sure I don't get the motor hotter than the manufacturer's recommended safe maximum.

Depending on the layout and size of the track, sometimes the best lap times over the duration of the run happen at a surprisingly low temperature...

Sometimes you can be geared to get super fast laps early in the run and get a fade in the later part due to getting deeper into the discharge curve of the battery, so I like to look at the lap times for the full run to make sure I'm gearing effectively...

Now if you're not racing on a circuit with timing equipment, then I'd have to go with feel... gear to where the car feels best to you, where you feel the balance of off the line acceleration and top speed suits you, and again, check temp to make sure you don't overheat anything.
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Old 04-28-2009, 06:15 PM   #4
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For me, gearing choice is all about the best lap times over the duration of a run, with temperature checks to make sure I don't get the motor hotter than the manufacturer's recommended safe maximum.

Depending on the layout and size of the track, sometimes the best lap times over the duration of the run happen at a surprisingly low temperature...

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Old 04-28-2009, 07:22 PM   #5
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When gearing, you are looking for your car to be as fast as possible without your motor cooking. You will have to gear according to layouts. If it is a very open layout make your FDR (final drive ratio) as low as possible for more top speed. If it is a technical track, make your FDR a little higher to get more acceleration out of your motor.
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Old 04-28-2009, 07:48 PM   #6
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I got a secret method.

When you get to the track, ask the guy behind the counter what everyone else runs with similar setups. Then gear accordingly from there. It gets you in the ball park a lot faster.

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Old 04-29-2009, 12:19 AM   #7
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Quote:
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I got a secret method.

When you get to the track, ask the guy behind the counter what everyone else runs with similar setups. Then gear accordingly from there. It gets you in the ball park a lot faster.

--pakk
i disagree with this statement I think when you get your gearing right on brushless motors you don't really need to change because they will be fastest on this gearing or 1 pinion either direction depending on the layout and temperatures on the day/night. And on the new speedos you can simply time your motor up slightly or down slightly to suit the layout as i find that when timing up you change the power at particular revs on the motor so if you turn up the timing it will have more grunt up high but lack a bit when taking off and if you go to low it will have incredible punch initially and then do nothing. But when you max out the timing on new speedos they usually increase the r.pm slightly as well.
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Old 04-29-2009, 12:31 PM   #8
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oh ok well i have a tc4 and i can never get a correct gearing,the curent gearing is 85/36 2s lipo with a monster 27t motor running on the street with rubber slicks. can someone help
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Old 04-29-2009, 01:32 PM   #9
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oh ok well i have a tc4 and i can never get a correct gearing,the curent gearing is 85/36 2s lipo with a monster 27t motor running on the street with rubber slicks. can someone help
That gearing gives you a 5.9FDR, which should run cool enough, but will be slow against similar cars. I've run a TC3 with some tired stocker motors and they start to cook pretty good at around 5.5. They're fast and way hot at around 5.3. Anything lower than that, wear Nomex when you pick it up.
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Old 04-29-2009, 02:24 PM   #10
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I gear to ambient temperature and track duration. Long tracks or Ovals means the motor is going to be running at its highest much longer. So, I may gear down to optimum speed, and aviod theremal shutdown. But I mostly gear to air temperature.
I made the mistake of not gearing to air temperature, and theremaled the motor. So, it's vary importent to make sure you know what the day is going to be like before you race, and gear accordingly.
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Old 04-29-2009, 02:47 PM   #11
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oh ok well im going to being racing in a few hours at a indoor place that has a lot of turn and a small straight so im switching to foam tires and a 19t motor and 2s lipo , does anyone have a good final drive ratio for that type of set-up
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Old 04-29-2009, 03:29 PM   #12
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I would think when running on a tight complex track gear for the most torque then gear up to get to speed and watch temps close each run. gear to the lowest fgr and at the same time keep temps not so high...
but most of all keep the car on the track while doing so
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