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Recommended gear ratio settings

Old 05-07-2022, 03:19 AM
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Default Recommended gear ratio settings

The recommended gear ratio for my atomic sz2 6500kv with 35t spur gear is to use a pinion gear of either 23t or 24t.

The supplied pinion gear is 28t. I have no intention of running at max speed, probably around 1/4 power as it'll be used around the house.

I've looked for the appropriate pinion (23/24t) but I don't think it exists for the sz2 yet. Would it be OK to keep the current 35t/28t/6500kv setup or should I consider getting a 4500kv motor to be in line with the recommended settings?

Thanks
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Old 05-07-2022, 06:06 AM
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If it's just around the house, don't bother. Or go with a slower motor. The tall gear might help reduce the acceleration and make it somewhat more controllable.
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Old 05-07-2022, 07:56 AM
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Thanks for the answer. I was thinking of limiting the throttle to like 30% too which should help. I'll see how things go and if required get a 4500kv in future.
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Old 05-07-2022, 02:21 PM
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reduce spur gear to high for 6500..id go down to 20 or less
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Old 05-08-2022, 03:34 AM
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Originally Posted by the rc guy View Post
reduce spur gear to high for 6500..id go down to 20 or less
Please excuse my ignorance (still learning), but wouldn't reducing the spur gear to 20 from 35 actually increase the top speed and put more strain on the motor?
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Old 05-08-2022, 05:47 AM
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Originally Posted by lazerlyte View Post
Please excuse my ignorance (still learning), but wouldn't reducing the spur gear to 20 from 35 actually increase the top speed and put more strain on the motor?
The closer to 1:1 ratio you get equates to top speed whereas a 4:1 or 5:1 is more torque. An example, when racing 21.5 fixed timing usgt motors you may be around 3.0-3.2. If you wanted a speed run set up you'd be running a larger pinion and smaller spur to get more top speed...closer to a one to one ratio like a 75spur and a 65 pinion.
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Old 05-08-2022, 05:54 AM
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Originally Posted by lazerlyte View Post
Please excuse my ignorance (still learning), but wouldn't reducing the spur gear to 20 from 35 actually increase the top speed and put more strain on the motor?
Just to clarify, you'll never need to be as low as a 1:1. The pinion is your motor gear and the transmission gear is your spur. So using your example, going from a 20spur to a 35 would be more torque. Now if you went from a 20 pinion to a 35 pinion that would be a big jump in top speed. Hope that makes sense.👍
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Old 05-08-2022, 06:39 AM
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Originally Posted by lazerlyte View Post
Please excuse my ignorance (still learning), but wouldn't reducing the spur gear to 20 from 35 actually increase the top speed and put more strain on the motor?
You are correct. reducing spur has the same effect as increasing pinion size. So the opposite of what you wanted.
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Old 05-08-2022, 07:56 AM
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Thanks for clarifying. Really helpful. I guess it's finding the right balance on where you intend to run, house or race track etc. I've been away from the rc scene since I was a young lad and back then I had the kyosho rocky. So lots of catching up to do!
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Old 05-08-2022, 07:16 PM
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i read every post in this forum you never said anything about top speed only thing said was running around hose in top speed lol.. i gave you a controllable gear ratio to run around house
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Old 05-08-2022, 07:35 PM
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Originally Posted by the rc guy View Post
i read every post in this forum you never said anything about top speed only thing said was running around hose in top speed lol.. i gave you a controllable gear ratio to run around house
Post #5.
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Old 05-09-2022, 12:21 AM
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Originally Posted by the rc guy View Post
i read every post in this forum you never said anything about top speed only thing said was running around hose in top speed lol.. i gave you a controllable gear ratio to run around house
I wasn't clear, my bad. Appreciate all the help in this hobby. I have spent a small fortune on getting the right gear (eg soldering iron, pliers, calipers, car upgrades etc), so I'm gathering all the info beforehand... Then going to relish every second of the build but seriously, you guys make all the difference in the hobby with the support you give.
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Old 05-09-2022, 04:55 PM
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Originally Posted by skater-deez1 View Post
Post #5.
still no mention in top speed wanted just my gear reduction would reduce t.
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Old 05-09-2022, 04:59 PM
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you di not spend a small fortune in items mentioned. Calipers can be had for under 12$ u.pliers if you looked around 10. solder iron less than 30. gears maybe 10 each those are Robinson
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Old 05-09-2022, 11:50 PM
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Originally Posted by the rc guy View Post
you di not spend a small fortune in items mentioned. Calipers can be had for under 12$ u.pliers if you looked around 10. solder iron less than 30. gears maybe 10 each those are Robinson
Remember, this is my first car since a long time. I did not list everything in my post as it would take me quite some time. Also please note, a small fortune is subjective. It may not be to you, but others it is. Many of the things I ordered are from overseas hence I need to pay an additional 20pc vat plus shipping.

Here are just a few of my components. I have ordered much more. So far I've spent over 1000, around $1300. As I say, small fortune for me. Might not be to you.

Atomic sz2 car
Atomic 24a receiver
Hv1820 servo
HV1885 servo
2 motors
2 batteries
Battery charger
Fly sky noble + receiver
Mini z patronas shell
Tools
Soldering iron plus tips
Carbon battery holder
Aluminum
Tyres and wheels x a few
Tyre tape
Carbon wide bumper





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