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Old 11-25-2003, 06:28 PM   #1
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12th scale stock rollout

I need help finding what is a good rollout for 12scale stock.How this is calculated and what you guys think is a good stock motor for 12scale stock.Thanks!
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Old 11-25-2003, 06:37 PM   #2
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Post 1\12th scale

any stock motor will do..... you dont have to bolt some mean stock motor to make those things haul some a$$......
as far as rollout..... there is none.... its direct drive..... but try to keep the spur size close to the diameter of the rear tire....... for starters try 48 pitch----say----- 78\24 or75\24
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Old 11-25-2003, 06:40 PM   #3
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Thanks but I need something a little more then vague numbers.I dont run 48 pitch so that wont work and I am sure there is a preference when it comes to which motors people run.Anyone else?
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Old 11-25-2003, 06:45 PM   #4
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Angry 1\12th scale

fine... run 3.1 to 3.25
and use fantom stock motors
.298 for your comm size.... teflon motor shims.... red springs positive and negative..... run reedy 767 brushes....
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Old 11-25-2003, 06:51 PM   #5
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I use around 41mm for rollout on a 80 X 40 track.
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Old 11-25-2003, 06:55 PM   #6
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Thanks..Now how do you calculate your rollout?This is the kind of info i need.I waded throught t12 scale thread but could not find the info I needed.Alot of posts!
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Old 11-25-2003, 07:02 PM   #7
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Rollout is the distance the car moves for one rotation of the MOTOR.

First find the gear ratio, then divide it by tire circumfrence.


Gear ratio is Spur divided by Pinion

Example 98/29=3.3793 to one.

Then find Tire circumfrence.

1.8" * 3.14 (pi)= 5.562

Rollout is circumfrence / ratio

5.562/3.3793=1.67

To convert to MMs, multiply by 25.4

1.67*25.4=42.4
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Old 11-25-2003, 07:06 PM   #8
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Default Oh Heck

Just go Here

http://www.teamcrc.com/phpBB2/viewto...hlight=rollout
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Old 11-25-2003, 08:44 PM   #9
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Default 1/12 roll out question

ok,
here's another question for all the 1/12 gurus here in rctech, assuming we've found a suitable rollout for a particular motor, how do we take into a/c tire wear? ie for each mm of tire wear, how many teeth do we go up on the pinion? is therea guideline to this? thanks for any input given..
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Old 11-25-2003, 09:15 PM   #10
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sure...it's called calculate the rollout that works...

Then re-calculate based on the new tire size and adjust your gearing accordingly...

It's just math folks..don't get lazy now
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Old 11-25-2003, 09:49 PM   #11
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Now that I have the calculation,its all good.Thanks Guys!
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Old 11-25-2003, 11:01 PM   #12
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Quote:
Originally posted by Windsorguy99
sure...it's called calculate the rollout that works...

Then re-calculate based on the new tire size and adjust your gearing accordingly...

It's just math folks..don't get lazy now
maths is something which i could never seem to pass in school.
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Old 11-26-2003, 12:12 AM   #13
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Racenut123, Heres a web site a friend of mine passed along to me. Its very good, you can print off a chart to take to the track.

check yes to the "target rollout chart"

Dennis

Oh yeah, no math involved
rollout
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Old 11-26-2003, 12:14 AM   #14
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I was using a 40-41mm rollout with a p2k and 46-47mm with a MHS
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Old 11-26-2003, 05:46 AM   #15
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Default 1/12th rollout chart

I've attached a chart that you can use to easily identify rollout. I use a 100 tooth 64 pitch spur gear, so the chart is limited to this setup.

However, if you know how to use Microsoft Excel, you can easily adjust the formula for the spur gear that you use and create a chart for each spur gear size.
Attached Files
File Type: pdf 12th_rollout100.pdf (6.3 KB, 185 views)
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