Motor RPM Speed Test Sharing

[MadAnt]

Just wanted to make a thread where members can collaborate and compare their own motor speed test data. Due to the marketing BS and the unknown performance specs of many electric motors in our hobby, I feel it would be pretty useful to have a space where we discuss and record our findings while making it a little bit easier for others to find the answer of... "How fast does this thing spin?"

Experimental and modified stuff is welcome too.

Here is my first test, with four mild hot 540 size motors.

Over the years I have bought and acquired some mild performance motors. Some of these 19 and 17 turn motors back then were a decent upgrade sometimes, which was apparent from the tire buning punch they packed, but still not to powerful to be insane. 

Ok, enough of the chit chat, here are the numbers. (Numbers have been rounded off and measured at 7.2 volts.)

Reedy Radon 17t: 24,200 RPM. Booo! Team Associated list the RPM at 25,000 - 30,000, but does not say at what voltage.

Venom Fireball 19t x2: 22,900 RPM. Advanced the timing another 3° and got 24,300 RPM, then cranked it another 4° and the RPM increased to 25,100. 

Team Orion Method SV2 17x2: 26,100. Well... almost, 10 RPM short, but maybe if I loosen the screws and wiggle the endbell I can get 10 more.

Kyosho Atomic Force 17x2: 22,500 RPM, but the timing may have been a degree or two past zero. Cranked 8° more and got a good improvement, reving to 25,500 RPM, another 5° and got 28,700 RPM.

Some final notes:

The most disappointing motor of this bunch was the Reedy Radon 30,000 RPM. Not only does it under perform, but it runs terribly hot, and it's not just mine. Years ago when I worked at a hobby store, we have sold some of these motors to customers and the complaint was that they run too hot. Lower gearing did fix the issue a bit, but then the car had a slower top speed. The lack of good ventilation on the can was the clear issue, so on mine I cut two vent holes on it.

The Team Orion Method SV2 17t motor performed pretty close to it's claimed RPM spec of 26,104 RPM at 7.2V. It probably needs a cleaning and maybe it might gain another 14 RPM to hit the rated number, but really it's pretty good that it's that close and proves that my homemade RPM test setup works well enough.

On the two motors I advanced the timing on, I will dial them back as I don't want to push them too much. They should be able to put out good speed at more conservative timing without cooking themselves. Also, I want these motors to last, 3 out of the 4 are not made anymore, with the Reedy Radon being the only one left in production.

 

[wolfdogstinkus]

What are you measuring the RPM with?.

I only ask as I downloaded an app (motor pitch analyser)that is supposed to estimate motor speed by listening to the pitch?, I don't know how it works and I haven't used it enough to judge it's accuracy.

I used it for the go kart motor but got a wildly different answer to the one specified for the motor, so I'm a bit skeptical about it's accuracy.

[MadAnt]

12 minutes ago, wolfdogstinkus said:

What are you measuring the RPM with?.

I only ask as I downloaded an app that is supposed to estimate motor speed by listening to the pitch?, I don't know how it works and I haven't used it enough to judge it's accuracy.

I used it for the go kart motor but got a wildly different answer to the one specified for the motor, so I'm a bit skeptical about it's accuracy.

I'm using a Cen-tech tachometer on my janky motor testing setup.

The multimeter measures the voltage going to the motor and the tach reads the reflective tape on the motor hub. It works pretty well, but is still jank to use, lol.

[River19]

Does brushless testing count?

 

[MadAnt]

4 hours ago, River19 said:

Does brushless testing count?

 

Umm... maybe.

Test it and post it.

[River19]

For reference this is a brand new tuned Fantom Helix 13.5 Brushless tested recently just prior to going into my 4wd L1R.

Good baseline of what an objectively high performance ROAR legal 13.5 looks like on the motor analyzer.

 

 

[MadAnt]

Alrighty, some more tests are coming in the future. I reached out to @GToddC5, who is interested in doing some tests and we can compare our findings on some upcoming motor tests. BTW, anyone can join in, the more data we have, the better.

For comparing the same brands and models we should test the rotational speed at 7.2 volts or the voltage tested by the manufacturer, other lower or higher voltages can be added as extra info.

Up for future testing I have multiple "stock 27 turn" 540 size silver can motors that Tamiya has included in their kits over the years. There are a few Mabuchi silver can motors I can't test, because one of them is in my F350 Highlift which is the shiny satin RS 540SH with the round sticker, and the other two I don't have, which one looks the same but is shinier and the other would be the white endbell motor from the 70's. I also don't know if I have all the Johnson 540J motors, but I have a few different types ready to test. 

[alvinlwh]

13 hours ago, MadAnt said:

For comparing the same brands and models we should test the rotational speed at 7.2 volts

My motor tester reports in Kv too, so it is possible to work out a the RPM at 7.2v?

[MadAnt]

4 hours ago, alvinlwh said:

My motor tester reports in Kv too, so it is possible to work out a the RPM at 7.2v?

You could, since motor kv is measured by calculating the motor RPM per volt (RPM÷Voltage=kv). If you have a common motor like a modern-ish Mabuchi RS-540SH 27 turn silver can that's used in many Tamiya kits, give a test and we can compare. Mathematically the results should be fine.

[MadAnt]

I did some testing on four Tamiya kit "stock" supposedly 27 turn silver can 540 motors and got some interesting results. It was a Mabuchi vs Johnson, very old vs new rev-off. I have to say, I was surprised with the results. 

The vintage motors were up first, both were crying from trying to move, it was clear that they needed a wash and the bushings lubed, but I just kept forcing them voltage until they woke and cleared up burning the dust out with lots of sparking from the brushes. Now with the old timers back to life, I let them run and cook at 7.2 volts for a bit more and they got a little bit faster before settling. For me the results of the old timers were both average and surprising.

These numbers have been rounded off slightly, but more often to a lower number. All testing has been done at 7.2 volts.

The old Johnson 540 with the white endbell spun and settled at around 17,400 RPM and 17,800 RPM in the reverse direction. Very well done for an old fart that may have lived as a front axle motor in a Clod probably.

Can the old black endbell Mabuchi RS-540 Silver Can beat the old Johnson? Umm... no. It performed as I expected and just revved to around 15,300 RPM.

Next up, the young timers. The Johnson 540J was already broken-in, but the Mabuchi RS-540SH was not because it was pretty much brand new still in the plastic bag that came from my CC-01 kit some 7 or so years ago. Anyway, I'm happy to report that both of these motors are faster than their predecessors.

The new 27 turn Mabuchi RS-540SH revved to about 16,400 RPM. The brushes have not had time to break-in, so there may be a little bit more in it.

The Silver Can Johnson 540J was a bit more awake revving to around 18,900 RPM. That's a good difference from the Mabuchi RS-540SH, I'm very pleased with that result.

So the winner is the New Johnson 540J, but even the vintage Johnson was faster than the newer Mabuchi RS-540SH. Some interesting results here, I would love to see what other members discover with their own tests.

Alright here is the TLDR:

Vintage White endbell Johnson 540: 17,400 RPM@7.2V.

Vintage black endbell silver can Mabuchi RS-540S: 15,300 RPM@7.2V.

New-ish Johnson 540J: 18,900 RPM@7.2V.

Mabuchi RS-540SH(Not broken in): 16,400 RPM@7.2V.

There are some factory/replacement stock silver can motors that are in-between these two generations that I might test in the future. I have a few of them, but they are currently in use right now(sort of).

[Wooders28]

Only motor test I've done.

4.5t,  blinky ,fully charged 2s, dusty painted workshop floor with bald tyres - 

 Vs, 

Only change, spiked tyres on astro

 

 

Pretty much consistent with the advertised no load box KV of 9100.

 

 

 

On 3/20/2025 at 11:28 AM, River19 said:

Good baseline of what an objectively high performance ROAR legal 13.5 looks like on the motor analyzer

There's a vid on YouTube , testing degrees of boost and turbo on one of those motors. Pretty much double the KV.

[River19]

1 hour ago, Wooders28 said:

 

There's a vid on YouTube , testing degrees of boost and turbo on one of those motors. Pretty much double the KV.

Yup, no doubt it is impactful.  Just can't run any of that in a Blinky class.......

[alvinlwh]

I have some new BL that I wanted to test and upload the results here before I realised that BL motors are not quite PnP. I need to solder on connectors/wires before I can turn them! As I am not ready to work on them yet, they will have to wait. 

So off to test some motors I had wired up but not installed. 

First is a Speed Passion 4.5R, it was scary. The screech nearly made my ears bleed! 

First attempt was a bit below spec of 8000Kv. 

I thought it was the HK XCar ESC that is "no good". So I swapped in a HW 10BL120.

Hmm... Similar results? Then I realised that the R has a +11 sensor that I swapped in a +0 board. So that must be why. 

Side note: it started to get warm after less than a minute on each ESC with no load. Now I am worried how to gear this without it catching fire. 

Next up, a Rocket V3 10.5t.

On the same HW ESC. 

On stock out of box +30.

So here are the results. 

Motor: SP 4.5R claimed 8000Kv with min +11 timing

Actual: 7000 - 7100Kv with +0 timing

Motor: Rocket RC V3 10.5t claimed 3800Kv

Actual: 4000Kv with +30 timing

NOTE:

1. My ESC is on 0 on all settings. 

2. I am surprised that the SkyRC program box works testing HK and HW ESCs too. 

[MadAnt]

Tested 3 more motors and my results are pretty much the same as the results other people have gotten.

(Some speed readings have been rounded off. All of my tests are done at 7.2 volts.)

Tamiya Torque Tuned: 19,575 RPM

Sport Tuned black can: 21,100 RPM

Traxxas 550 Titan 23T: 14,000 RPM

I threw the old 550 Titan in just for fun, it's definitely slow, but it was meant to be ran at 14.4 volts. Since it has good torque, I have one in my Trail Finder II.

Maybe I might test some crawler motors in the future and see which one is the slowest lol.