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How Free is a Free Drive Train??

How Free is a Free Drive Train??

Old 08-01-2004, 09:49 PM
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Default How Free is a Free Drive Train??

Yes... BIG question... how free is a free drive train??? especially on a shaft driven car???
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Old 08-01-2004, 09:51 PM
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If you spin a drive train with the wheels on and it rotates on its own and "glides" to a stop, it is free. You can do a ton of work to get it more free than that, but getting it to that initial point is the most important.

If you spin the drivetrain and it seems to suddenly stop instead of gradually stopping, or if it is difficult to "roll" the spur gear with your finger, then there is something wrong and it needs to be freed up.
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Old 08-01-2004, 10:15 PM
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you should be able to breath on it wrong, and it will roll... , no but seriously, what Shane said is correct...
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Old 08-01-2004, 10:26 PM
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Originally posted by futureal
If you spin a drive train with the wheels on and it rotates on its own and "glides" to a stop, it is free. You can do a ton of work to get it more free than that, but getting it to that initial point is the most important.

If you spin the drivetrain and it seems to suddenly stop instead of gradually stopping, or if it is difficult to "roll" the spur gear with your finger, then there is something wrong and it needs to be freed up.
I agree with what you said here... but, what kind of work we can do more on the drive train to make it as free as it can...
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Old 08-01-2004, 10:30 PM
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Do not mistake inertia as a measurement of a free drive train.

A drive train will spin for a long time the heavier it is due to the momentum generated by the rotating parts.

Take the wheels off a car and spin the drive train again and it doesn't spin as long.

You get the idea...
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Old 08-01-2004, 10:48 PM
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If the drive train moves when you blow on it without the wheels, it's free.
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Old 08-01-2004, 10:52 PM
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you guys are probably more experienced than I am, but what I do to check how "free" everything is, is this....
spin each cvd individually to eliminate any problems there...
they should be very smooth and no resistance....
then I take the shaft out and check the rear diff by setting my finger on the spur and turning it slowly... so that I can FEEL for any bad spots... kinda like someone trying to pick a combo lock...lol usually there will be one or two spots of resistance.. on my tc3 its always the small bevel gear being out of center..
after that is smoothed out I then do the same with the front diff....
check one thing at a time and use the process of elimination..
maybe thats taking it too far but its how I do it...lol
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Old 08-01-2004, 11:15 PM
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Originally posted by Neil Rabara
If the drive train moves when you blow on it without the wheels, it's free.
Lol, just the ceiling fan in my room makes it spin...
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Old 08-01-2004, 11:20 PM
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Default Free drive-train

My SD spins about 7 secs with tyres on it, but I heard Masami's does about 20 secs.
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Old 08-01-2004, 11:22 PM
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masami's probably spins for a couple of days, but that is just because he is Masami and he is the Bomb Digity, YO!!! (damn I love saying that)
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Old 08-01-2004, 11:26 PM
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Originally posted by =MisFitz= NuKe
masami's probably spins for a couple of days
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Old 08-01-2004, 11:29 PM
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Originally posted by =MisFitz= NuKe
masami's probably spins for a couple of days, but that is just because he is Masami and he is the Bomb Digity, YO!!! (damn I love saying that)
Yea and then there was the story about how the wind kept blowing during the A main final and they couldn't start the race till the wind died down coz Masami's car couldn't keep still on the grid.
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Old 08-02-2004, 12:10 AM
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I've seen Lex Tyler's drive train (TC3) and it spins for 30 seconds no problem. I've heard he and some of the guys at RC Tech timed it once when he really got into it and it did 1:20. I didn't believe it until I saw for myself. Pretty impressive.
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Old 08-02-2004, 12:13 AM
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Wait, how do you get it that smooth?

and

When you say "spin the drivetrain" you mean open the throttle up full and then let go, right?
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Old 08-02-2004, 12:27 AM
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Donoman:

Take off the pinion gear. Spin the rear wheels or whatever as hard as you can. That's how I do it.
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