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User avatar
By ms1120
I have spent my last few days recovering and my spare time searching the forum. I couldn't find this anywhere else and it's come up a lot. This information has been spread out over a few different posts but I didn't see it all in one place. There is a link in the FAQ called Motors that Work ... hichpage=1 and if you have a few hours to see thread jacking gone bad, take up this read. Most of the links, especially the ones for motors, are bad now. There is alot of good information there but you have to look for it. Hopefully, this one will help some newcomers.

Many people want their BPROs (battery powered ride ons) to go faster, have more torque or accept more voltage. In most of the BPROs, a 500, 600 or 700 series, brushed, electric motor is used. This series is also found in a lot of Radio Controlled cars, trucks, planes and boats. Being that it is fairly common, there are a lot of different companies out there that make them. Some of the older or bigger units use a 700 series motor. There are aftermarket offerings in both of the above sizes.

Here are some things that you should know before you start replacing the factory motor with an aftermarket one. These tips should help you to avoid making a purchase of something that will fail in only a few hours or days.
stock Tamiya 540.jpg
a stock Tamiya 500 series motor (non-rebuildable)
stock Tamiya 540.jpg (8.23 KiB) Viewed 29357 times

Tamiya 25t.jpg
an aftermarket Tamiya 500 series motor (rebuildable)
Tamiya 25t.jpg (25.12 KiB) Viewed 29357 times

Before I start, here are a few Definitions to help:
-Armature-The shaft that runs through the motor and contains the windings, the commutator and the core. It has a bearing or bushing on each end to keep it in line.

-Brushes- The primary contact point for the current to make it into the motor. The brushes are connected on one end to either the positive or negative input wire and on the other end they contact the commutator. Brushes are not replaceable on sealed motors but are replaceable on most aftermarket ones.

-Commutator- The part of the armature shaft that allows for current to pass through the brushes and into the windings.

-End Bell- The end cap for an electric motor that holds a bushing or bearing and on stock BPRO motors, holds the power input tabs. On an aftermarket motor, the end bell also holds the brushes and the springs. In a factory motor, these are sealed with metal tabs holding it on. On most aftermarket motors, these have screws holding them on.

-Timing- Has a significant impact on R/C car performance. Timing can be found with rebuildable and non-rebuildable motors. Most all aftermarket motors have some timing added from the factory to make it perform better. This is why some offer a “Reverse” rotation motor so that the timing will be even between the two motors while they are running in opposite directions. More timing means more speed but less torque. Less timing means less speed but more torque.

-Turns- Refers to the number of times a wire, usually copper, is wound around each pole of an armature. For example a 27 turn motor. The higher this number is, the lower the RPMs but with higher the torque and longer the battery life. The lower the number (like a 10 Turn motor), the higher the RPMs but with lower torque and less battery life.

-Winds- Refers to the number of wires wrapped around each pole of the armature making the above mentioned turn. This is usually the second part of a motors spec like 27 turn Single, Double, Triple or Quad. A single motor wound motor make more torque in the lower RPM range whereas a Double, Triple or Quad wound motor makes more torque in the top of its RPM range.

Now the Meat and Potatoes portion
-Factory BPRO motors are sealed units that are not rebuildable and shouldn't be taken apart. The metal tabs that are holding the end bell in place will likely break if you remove them. The brushes inside will also come out of their holders and are very difficult if not impossible to get back together.

-Aftermarket motors are not always sealed units. Most of the ones built for the R/C world are rebuildable so that the brushes or springs can be replaced. This also allows for the cleaning of the commutator, as it gets dirty over time.

-Aftermarket motors are designed for R/C applications. There are some exceptions in the robot market but most of the motors are designed to move a 3-6lb vehicle. Through gearing, they will power our BPROs just fine as long as we follow some rules. A BPRO stock 550 or 600 series motor is between 32 and 35 turns depending on who you ask. If that’s the motor that the factory decided would last the best, how long do you think a 10 turn motor will stay together? Not very long. A motor that is 21 turns or numerically higher will last longer. The R/C motors are also designed to operate within a range of 6-16 volts. That’s where it pays to get the FULL motor specs before you buy one. If it’s designed to make 31000 rpms at 8.4 volts, it probably will not last long at 18 volts. If it’s designed to operate at 18 volts but only makes 5000 rpms at 18 volts, why would you want it? Do your homework and ask the manufacture for a spec sheet.

-Aftermarket motors sometimes have factory built in “timing”. If you buy 2 motors and they are sealed units but they have 3 degrees of advanced timing, you shouldn’t run them as a pair. Make sure that the motors you buy either have zero timing when using them as pairs or buy them as a standard and reverse rotation package. Again, it pays to get a spec sheet from the manufacturer.
-Aftermarket and stock motors are designed to operate within a specific RPM, Voltage and load range. Overvolting is a common practice among the MPW clan. When a stock motor is overvolted, it puts out more RPMs than at its stock setting. The bonus is that this is the quickest way to make a BPRO faster. The downside is that overvolting creates heat and resistance that translates into eventual motor failure. The windings on the armature are usually covered with an epoxy resin. When the motor gets super heated, it causes this resin to melt in the motor casing and makes the “magic smoke” appear out of the motor compartment. There are ways to slow this down and speed this up.

Slow failure down-
Under gear the vehicle by going to a numerically higher gear ratio. This will add torque but will not add much speed.
Increase the wire size being used throughout the BPRO. This will lower the resistance in the wiring and translate into less heat at the motor.
Add heat sinks and/or fans to the motors. This will help the little fan in the motor to cool the motor canister off. Cooling the motor will keep the epoxy from melting and ruining the motor.

Speed failure up-
Over gear the vehicle by going to a numerically lower gear ratio. This will add more speed but will decrease torque. Decreasing torque will cause the motor to work harder and generate heat faster.
Use smaller wiring at any junction in the BPRO. This will increase resistance which translates to more motor heat and we already know what that does.
Overload the BPRO. I know we all want to ride them too but when we place a 250 pound person on the Dora Quad and joy ride in the cul de sac, we are asking for failure. This works like over gearing but worse. Now we are increasing the load on the motor usually till it stalls. When it stalls, the brushes burn a spot on the commutator and create a place that the power can no longer transfer through. This will also increase the heat so fast that they are destined to fail.

I hope this helps someone and keeps them from spending alot of money in the wrong direction.
Last edited by ms1120 on Tue Jan 24, 2012 10:12 am, edited 4 times in total.
User avatar
By ms1120
To add to anyones confusion who may not be confused just yet about all this motor nonsense, I have the specs for what is considered to be a factory Power Wheel 12v motor. This will help give you a baseline of specs when you start looking for a replacement BPRO motor.
This motor is listed under Johnson Electric's catalog as being for a 12v BPRO.
Johnson #HC683LG-001
RPM 12volt (no Load) 15694
Current (no Load) 1.18A
Stall Torque.......400.13 mN-m

If you are looking for a direct replacement that may offer a few more RPMs, has these
for a fair price.
This should be a decent upgrade for a stock motor. Just remember that if you have 2, you will need to change them both to the newer motor.
For a speedier replacement these Duratrax motors are lightning fast on 18v, or so Ive been reading. Duratrax #dtxp5737 . They are designed as a starter motor but work well at 12v to 18v.
Borrowed from the old site
Finding these for me wasnt that hard and Ive ordered a set that will be here soon. Again, if you buy this or any replacement motor, you should replace all of them in the same vehicle with the same motor.
Last edited by taz11 on Tue Jan 24, 2012 7:01 am, edited 5 times in total.
User avatar
By ms1120
The 6volt BPRO Johnson motor is also in their catalog
RPM 6V (no Load) 14500
Current (no Load) 3.03A
Stall Torque.......308.22 mN-m

Im hoping that these specs will help people when they are trying to determine what combination will work best with different parts. This will also allow you to gauge (with a little math) what the top speed of your vehicle may be.
Last edited by taz11 on Tue Jan 24, 2012 7:00 am, edited 2 times in total.
User avatar
By ms1120
One of the things I noticed while reading the old "motors that work" thread (and I read the WHOLE thing) was that alot of people became discouraged that they couldnt find suitable replacement motors. Some even willing to quit PWs all together and move to gas powered carts or ATVs.
Since that thread was started, there have been alot of members come and go. Some of them were looking for an instant speed doubling from a motor replacement. Grant (and he would know) reminded them that there were more factors involved than just motors.
Here was what he mentioned:
There are 6 major components to PW Speed
- Motor speed
- Motor Torque
- Gear ratios
- Wheel Size.
- Weight
- Energy loss (Friction etc)
It is just a matter of finding the correct combination

The one common thing that I kept noticing was that everyone was looking for a motor that had more speed, more torque or would handle more volts without snapping. The reality is that there arent alot of options out there. Allelctronics had motors that were being offered at the time and now arent available anymore. During the time they were available, folks from MPW bought them like crazy. Some had success with them and some didnt. Now days we are using R/C truck motors to try to fill that void. But the facts remain, it will take a combination of things, like Grant said, to make it all happen.
I often think that the newcomers opinion is that someone has a secret "black label" motor that they are sitting on that will transform the plastic cars into speed machines but it's kept a secret. That simply isnt the case. As I go, I will post everything that comes to mind on motor replacement in this thread and hope it doesnt get jacked to pieces.
Last edited by ms1120 on Mon Jan 23, 2012 2:45 am, edited 2 times in total.
User avatar
By ms1120
Another thing that I havent talked too much about is heat sinks. A heat sinks job is to help the motor dissipate heat. Imagine them as acting like your cars radiator. Your engine generates heat, the heat is transfered to the radiator via the coolant and as air passes across the radiator it cools down.
There are basically 2 types of heat sinks that are available. One is a standard clamp on heat sink that is attached to the side of the motor.
MHS-B-4.jpg (24.63 KiB) Viewed 29277 times

This is a fairly inexpensive and easy to install way to help the motors cool and extend their service life. These are found at most any r/c hobby shop and all over the internet.
The second type is a little more expensive but is the next logical step if you are trying to keep motors cool and a basic clamp on heat sink isnt doing the job. Heat sinks with fans are powered by either the cars existing battery or from an accessory battery.
Photo Courtesy of
intc2450.jpg (17.45 KiB) Viewed 29277 times
These can provide even more heat dissipation by moving air across the motor and heat sink. Make sure that you check the input voltage on fan powered heat sinks before you wire them. Some are designed to operate at voltages that are less than the vehicle you are installing them on.
If you are considering pushing the voltage limits of a BPRO or are adding aftermarket motors, it makes good sense to add heat sinks at the same time. Keeping the motors cool will not only extend their service life but it will allow them to run more efficiently.
User avatar
By ms1120

In the old forum, Johnson Motors had one of our members contact a company named Testco, out of Sunnyvale, CA, for purchase of the OEM motors. To try to keep my information up to date, I contacted Testco about Johnson motors including the 2 OEM ones listed above. The first email I got from them today stated " This motor is no longer available, please see our website for our standard stocked motors by Johnson.
Kerry Costa
NLA? Seriously? Doubtful. So here was my response
"Is it the case that they are in Johnsons catalog, yet arent available or is it that you guys just dont sell these two particualr units?
Nothing that was on the website in the link will work in the applications that I am working with.
And for the contradicting response that I got back
"We stock a very limited line of motors from Johnson, what we stock is on our site along with the spec. and pricing, if you do need something we do not stock, the min order qty. is 5,000pc."
So in less than 6 hours we went from they were No Longer Available to We dont stock them but if you want them it will be a 5K piece minimum. Thats at about 16 dollars each, BTW.
Now can you see how the older members got discouraged by the lack of aftermarket cooperation?
Here are some specs that I found from Mabuchi. If you can find these motors, they are direct replacement type BPRO motors ... 50pcvc.pdf
Last edited by ms1120 on Mon Jan 23, 2012 7:59 pm, edited 2 times in total.
User avatar
By ms1120
This will be the motor spec section of this thread. Alot of the aftermarket motors do not list their full motor specs in any of the catalogs or retailers. So, I took it upon myself to contact them as I could find valid email information.
First up...Good Old Traxxas Titans. You would think they would want you to know what was going on under the can of those motors. Here's what happened with them
"Can you please provide all the technical specs for the 21T and 23T Titans? I am specifically interested in Torque, stall and rpm per volt. Thank You"
The response?
"Hello Mike, Unfortunately our Engineering department does not release that information.
Best regards,Steve LindholmTraxxas Customer Service"
Seriously? LOL.
Then I tried Venom motors. Venom offers a pretty decent like of motors for everything from R/C street cars to rock crawlers. I asked for all the specs, this is what they sent
fireball specs[1].JPG
Some Fireball Specs

Atleast they sent something.
I also found a motor at It is a 500 series motor and I asked for the specs on it as well. Heres what I got back
Lunar model CR-505BS. 6-12 VDC, 0.8-4.5 amps - no load to max. efficiency. 18,000 rpm, reversible rotation, duty continuous. Designed for use in animated design. Shaft: 1/8" diam. x 7/16". Mount: 2 tapped holes on face 1" c/c. Overall dimensions: 1-1/2" diam. x 2-1/2". New condition"
gf774.gif (10.52 KiB) Viewed 29252 times

I will add more information as it comes in from the different vendors.
User avatar
By taz11
Here are some specs from BaneBots website.

This motor should be faster than a stock 12 volt and still have more torque......I have not used it, but it looks like a good bet at less that $8 each.

Motor Specifications Performance
Model M5-RS550-12
Operating v : 6v - 14.4v
Nominal v : 12v
No Load RPM : 19300
No Load A : 1.4A
Stall Torque : 68.85 oz-in 486.2 mN-m
Stall Current : 85A
Kt : 0.81 oz-in/A 5.7 mN-m/A
Kv : 1608 rpm/V
Efficiency : 70%
RPM - Peak Eff : 17000
Torque - Peak Eff : 8.84 oz-in 62.4 mN-m
Current - Peak Eff : 10.9A
Weight : 7.7 oz (218g)
Length - for motor : 2.24 in (57mm)
Diameter (with flux ring) : 1.52 in (38.5mm)
Diameter (no flux ring) : 1.41 in (35.8mm)
ShaftDiameter : 0.12 in (3.2mm)
Shaft Length : 0.3 in (7.6mm)
Mounting Screws (2) M3

These are 700 series. They will fit Metal frame jeep gearboxes and #7s gearboxes (with a 3/32-1/8 shim). This is what I use in my 24 volt ESC mods. They are astounding! Not sure if stock wiring can handle them. They are currently under $18 each.

Motor Specifications Performance
Model M5-RS775-18
Operating v : 6v - 20v
Nominal v : 18v
No Load RPM : 19500
No Load A : 2.7A
Stall Torque : 166.4 oz-in 1175 mN-m
Stall Current : 130A
Kt : 1.28 oz-in/A 9 mN-m/A
Kv : 1083 rpm/V
Efficiency : 78%
RPM - Peak Eff : 17040
Torque - Peak Eff : 23.99 oz-in 169.4 mN-m
Current - Peak Eff : 18.7A
Weight : 11.9 oz (337g)
Length - for motor : 2.81 in (71.3mm)
Diameter (with flux ring) : 1.85 in (47mm)
Diameter (no flux ring) : 1.66 in (42.1mm)
ShaftDiameter : 0.2 in (5mm)
Shaft Length : 0.3 in (7.6mm)
Mounting Screws (2) M4
Last edited by taz11 on Tue Jan 24, 2012 6:48 am, edited 2 times in total.
User avatar
By ms1120
Motor Can Size?
There are basically 3 different sizes/types of motors that are either found or can be used in a BPRO.
I will go ahead and make some folks argue with me but the Johnson Motors are not 500 series motors. They are and have been 600 series motors. Don’t worry; I have research on my side. The use of the term 500 series motors, particularly 550 and 540 series, as it relates to BPROs, has likely been derived from the R/C background of a lot modders.
The Johnson motor that is traced all the way back to the old forum is a 600 series in the eyes of Johnson. It’s in black and white in their catalog. As a matter of fact, their catalog doesn’t even show a 500 series motor. That’s where Mabuchi comes in. They made motors for most R/C cars and still make a lot of them. Mabuchi doesn’t have a 600 class motor but they do have 500 and 700 class ones. The measurements of the 600 series Johnson and the 540 series Mabuchi are the same diameter wise.

Now, the most noticeable difference between the 700 series motor and the 500/600 series motor is the canister (can) size.
Measuring the diameter of the motor, where the terminals come in to the back, a 500/600 series motor should be 35.8mm or very close to it. A 700 series motor should be 42.2mm give or take a tenth of a mm. The Canister length on a 500/600 should be between 50 and 57 mm long (depending on if it has an internal fan or not) and the 700 series should be 60mm long. This is not measuring the shaft of the terminals, just the canister.
So the fastest way to determine (unless you can tell by looking) which motor you have is to measure the diameter of the canister. Do not, however, measure the canister at the sleeve or band that is around a lot of motors. This will give you an inaccurate measurement.

So what’s the big difference?
As compared to the 500/600 series of motors, the 700 generally operates with more torque, efficiency and can handle more voltage. Torque is very important in BPROs as you can have way too much or way too little if you aren’t careful. So what we are trying to obtain is a happy medium while still being able to get the result we are looking for. Torque is defined as a measure of how much a force, acting on an object, causes that object to rotate. Torque is measured, on electric motors, mostly in metric units “mNm” and “g-cm”. The higher the number on motor specs, the more torque it will have. Here’s a side by side to show you what I mean. ... 50pcvc.pdf V/S ... 55vcwc.pdf

Mabuchi RS-550VC-7525 (this is a factory BPRO motor as well)
Operating Range 6.0V-14.4V
12V Constant
No Load
Current 1.20A

Max Efficiency
Current- 10.1A
mN-m- 58.3
g-cm- 594
Output- 95.9W

mN-m- 549
g-cm- 5596
Current- 85.0A

Mabuchi RS-775VC-8514
Operating Range 6.0V-14.4V
14.4V Constant
No Load
Current 2.70A

Max Efficiency
Current- 18.4A
mN-m- 111
g-cm- 1127
Output- 204W

mN-m- 863
g-cm- 8794
Current- 125.0A
Last edited by ms1120 on Tue Jan 24, 2012 9:57 am, edited 3 times in total.
User avatar
By ms1120
As you can see from the post above, the 700 series motors is more powerful. This is a much better choice than a high rpm motor with no torque. A chain saw has a 2 stroke motor, capable to very high rpms but doesnt produce alot of torque. A 500 cubic inch Cadillac motor red lines at about 5000 rpm but produces alot of torque well before that. You wouldnt want to swap these motors as the Chainsaw motor wouldnt push the Cadillac and the Cadillac motor would be overkill for the chainsaw (though it would be cool). Not much different here with PW motors.
Another VERY important factor to consider when you want to upgrade to a 700 series motor is the mounting. Most all 500/600 series motors (found in most all PWs) have a 25mm center to center mounting hole setup. A 700 series mostly has a 29mm center to center mounting set up for its bolts. That means that they may not be a bolt on application so once again, its important to get the spec sheet before you buy. Also, 700 series motors generally use larger diameter bolts on the motor mounting so you will need to make sure you either order new bolts for the motor or have a hardware or R/C store nearby.
Almost forgot....Pinions.
Since the 700 series motors usually have a larger diameter shaft (once again, spec sheet), a standard 500/600 series pinion may be too small. You can either drill them (which I dont recommend doing for someone if you havent tried it before) or you can order a set when you order your motors. Unless you want something crazy, you can purchase a commercially available pinion for the 700 series motors in 32 pitch just like you can for the smaller 500/600 series motors. Make sure that you get the right pitch and tooth count for your particular application. Im not going to go too indepth with pinion pitch here since its already covered in the Difinitive GB thread here viewtopic.php?f=41&t=103.
Last edited by ms1120 on Tue Jan 24, 2012 10:42 am, edited 1 time in total.
That is correct! Bolt spacing is different. The metal frame gearboxes come with 700 motors (a somewhat more mild version of the one I listed above) so it is a direct fit. #7's have a second set of holes that will work with the 700s. You will need to take a trip to the hardware store for different bolts.
Last edited by taz11 on Tue Jan 24, 2012 10:39 am, edited 3 times in total.
So, I wrote Mabuchi about the RS-775VC-8514‏
This thing would be great for PWs. Here's their response.
Dear Sir/Madam, Thank you for being interested in our products. We would like to inform you our motor is not available in the smallmarket.We make it a rule to have business with OEM maker directly. (ouracceptable minimum quantity is 10,000pcs per order)Because, we don't have any stock for each motors, also there is nodistributor. If you make the order to our products, we would like to know about yourapplication (purpose of use),operating voltage and other technical information etc....then we can select most suitable motor for your use/application. As for motor cost, we have no price list because we produce motor forindividualuse for each customer / for each application.That means that motor specification for each customer is different,Finally, we will offer our motor price after motor specification isfinally determinedafter some sample tests and your approval. Therefore, we recommend you to fill in the inquiry sheet in our home page.Then we can take appropriate action for you. ... _0400.html Your kind understanding would be very much appreciated.
Sincerely, S. Maeda

Not much help unless anyone wants to help me preorder 10,000 units. lol
I will go in on the pre-order. Count me in for four. :lol:
wired wrote:Do you have any specs on the mabuchi 74440-0640 motors?

That looks like a PW number, not a mabuchi#. The exact mabuchi number is probably not on them. It should be along the same lines as most stock PW 550s. Rpm is about 15200-16000. Torque is somewhere around 380-420 m-nm.
taz11 wrote:That is correct! Bolt spacing is different. The metal frame gearboxes come with 700 motors (a somewhat more mild version of the one I listed above) so it is a direct fit. #7's have a second set of holes that will work with the 700s. You will need to take a trip to the hardware store for different bolts.

so those 8514's in your sig are faster than stock, and have more torque. have you used these yourself (duh moment maybe, but wanted to check).

I have the 16t gearboxes that have both holes and want to put it on my escalade, besides the 4mm bolts and a spacer (needed?) will they just plop in the other holes? and I dont plan on going more than 18v on them (mostly at 12v for now), will the regular wires hold up? to 12v and 18v (not even going to touch 24v).

Do we not have a definitive list of Motors that will work with most of our applications? maybe a list of motors that will work along with a review or what to expect out of each motor...such as torque, high end and where to purchase....I just see a lot of people using the HPI 550's...I know Taz uses Banebot 775's and I've used the Banebot 550's.....I've also seen mention of Titan and some others. So is that something that is possible to come up with or too many variables?
I tried mentioning that earlier this week:

But did not seem to get a lot of response... [shrug]
Wow...I was three days behind you on that one....I like what you posted there....and yep, I'm still trying to get to the testing of the Banebots, but early trials are showing quite a jump in speed at 18volts over the stock motors. I am all for this list to be made...and you certainly have a good start going
Can someone tell me which 700 series motor if any will bolt right up to my stock gearboxes in my escalade. If not then what is a good pairing to replace them both. (Motors and gearboxes) I am running 18v and would like a 700 series motor with a durable gearbox.
Wow, lots of information, good stuff. I'm looking for a replacement for a 24 volt motor. printed on the motor is "24V 14000RPM" and there is a serial number. Just looking for a replacement, the other motor is fine. It comes off of a Motiontrendz quad.
Any help is greatly appreciated.
I am looking to run 18v and would like a 700 series motor with a durable gearbox. Can someone give me an idea if the 700 will bolt up to a stock #7, if it will work together, and if not what gear box should I get to run with a 700 motor? Thanks
Very helpful video. Thanks!! Do you sell gearboxes with hardware? I have two jeeps I'm working on and an older PW Mustang. I believe they all have the #7 gear boxes. I want to beef up the motors and go 12-18v.
I'm sorry I do not have any gearboxes for sale right now, I normally hoard any gearbox I can get my hands on, but you can find them on eBay and in the for sale section here. What are you looking for?
I just received 2 hpi gt550 motors and I am a little disappointed with their size. I expected them to be the same size as the stock motors but they are actually like 1cm shorter but same diameter. Anyways I hope they do well.

Sent from my iPhone using Tapatalk
Ok, so the right rear motor went out on my son's Boss Mustang. I am looking for a replacement and this is what I am looking at. ... p5737.html

I am also planning to add heat sinks with fans. ... R&CartID=1

Does anyone see any issues with these replacements/additions? I am assuming the motors spin one direction. How do I install them so they go forward and reverse in tandem?
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