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Tamiya M-03 vs. M-07 speed

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Tamiya M-03 vs. M-07 speed

Old 03-25-2020, 07:58 PM
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Default Tamiya M-03 vs. M-07 speed

I've been running an M-03 with Tekin Gen2 21.5 motor, Tamiya TBLE-02s esc, and 20T pinion.
Recently I built an M-07 with Reedy Mach3 21.5 motor, Tamiya TBLE-02s esc, and 20T pinion.

The M-07's top speed is significantly less than the M-03.

Any ideas why?
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Old 03-25-2020, 08:35 PM
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Do both cars have the same Internal Drive Ratio and are you using the same spur gear?

Calculate the FDR (Spur/Pinion X Internal Drive Ratio) and make sure they are the same. If the speed difference is till quite big then check to see if the M-07 rolls smoothly. There could be something that is binding or causing rolling resistance.
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Old 03-25-2020, 09:52 PM
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Originally Posted by tak4 View Post
Do both cars have the same Internal Drive Ratio and are you using the same spur gear?

Calculate the FDR (Spur/Pinion X Internal Drive Ratio) and make sure they are the same. If the speed difference is till quite big then check to see if the M-07 rolls smoothly. There could be something that is binding or causing rolling resistance.
You don't appear to have much familiarity with the Tamiya M chassis cars. They only have one spur gear option, it's not compatible with typical spurs. They have the same (rough) internal ratio.

It's most likely a binding issue (new bearings don't roll as freely initially) or an ESC calibration issue. Or the fact they're using two different motors.
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Old 03-25-2020, 09:55 PM
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Originally Posted by Tomoz View Post
I've been running an M-03 with Tekin Gen2 21.5 motor, Tamiya TBLE-02s esc, and 20T pinion.
Recently I built an M-07 with Reedy Mach3 21.5 motor, Tamiya TBLE-02s esc, and 20T pinion.

The M-07's top speed is significantly less than the M-03.

Any ideas why?
Try swapping the motors between the cars to see if the M07 goes faster and the M03 goes slower.
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Old 03-26-2020, 02:38 AM
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What giga said
+1
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Old 03-26-2020, 08:21 AM
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Originally Posted by gigaplex View Post
You don't appear to have much familiarity with the Tamiya M chassis cars. They only have one spur gear option, it's not compatible with typical spurs. They have the same (rough) internal ratio.

It's most likely a binding issue (new bearings don't roll as freely initially) or an ESC calibration issue. Or the fact they're using two different motors.

Thank you -- are you pretty sure the IDR for M-03 and M-07 are roughly the same? The M-07 manual lists the IDR but the M-03 doesn't.
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Old 03-26-2020, 09:44 AM
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Gigaplex has the simplest solution - swap motors and see if the differences in speed follow the motor.

It also wouldn't hurt to swap batteries between cars. A bad/weak battery can affect top speed of a car

----------

Other things to consider...

- Make sure the slow car doesn't have any mechanical issues
- Make sure both cars are using the exact same tires
- Make sure both cars are using the same transmitter settings such as throttle EPA (end point adjustment)

And finally since both cars have different motors, you may have to adjust motor timing to get both cars to run the same top speed (if applicable or allowed if you are racing these cars).
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Old 03-26-2020, 09:50 AM
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From a Google search, I found that the M-03 mini has an internal ratio of 3.134. I also found the following info on FDR:

Final drive ratio using 20T = 5.7979 (Rounding figure 5.80)
Final drive ratio using 19T = 6.1028 (Rounding figure 6.10)
Final drive ratio using 18T = 6.4419 (Rounding figure 6.44)

The M07 can take pinions from 17-24T with the following gear ratios suitable for stock racing:
  • 17T - 6.795:1
  • 18T - 6.418:1
  • 19T - 6.080:1
  • 20T - 5.776:1
  • 21T - 5.501:1
  • 22T - 5.251:1
  • 23T - 5.023:1
  • 24T - 4.813:1
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Old 03-26-2020, 10:48 AM
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I have a M03 and my solution is to use a 13.5T w/18T and I am happy. There was an aftermarket gear kit for M03 to make it faster but I forgot the brand. It could be 'Kose'
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Old 03-26-2020, 12:56 PM
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Originally Posted by Dealer Xing View Post
I have a M03 and my solution is to use a 13.5T w/18T and I am happy. There was an aftermarket gear kit for M03 to make it faster but I forgot the brand. It could be 'Kose'
Ride make the M-03 high speed gears.
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Old 03-26-2020, 02:59 PM
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Thank to all for the excellent advice
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Old 03-26-2020, 07:45 PM
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Originally Posted by SteveM View Post
From a Google search, I found that the M-03 mini has an internal ratio of 3.134. I also found the following info on FDR:

Final drive ratio using 20T = 5.7979 (Rounding figure 5.80)
Final drive ratio using 19T = 6.1028 (Rounding figure 6.10)
Final drive ratio using 18T = 6.4419 (Rounding figure 6.44)

The M07 can take pinions from 17-24T with the following gear ratios suitable for stock racing:
  • 17T - 6.795:1
  • 18T - 6.418:1
  • 19T - 6.080:1
  • 20T - 5.776:1
  • 21T - 5.501:1
  • 22T - 5.251:1
  • 23T - 5.023:1
  • 24T - 4.813:1
The M03 only supports 3 different pinions - 20T, 18T and 16T.
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Old 03-26-2020, 07:47 PM
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Originally Posted by Tomoz View Post
Thank you -- are you pretty sure the IDR for M-03 and M-07 are roughly the same? The M-07 manual lists the IDR but the M-03 doesn't.
Yes. With a 20T pinion, M07 is 5.78 and M03 is 5.80 (rounded to 2dp)
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Old 03-27-2020, 04:24 AM
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Originally Posted by gigaplex View Post
The M03 only supports 3 different pinions - 20T, 18T and 16T.
The numbers I posted were found online and I did not verify as I do not have an M-03 mini. I was just trying to help.....
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