Installing New Motors on Power Wheels

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Introduction: Installing New Motors on Power Wheels

About: I love working on and modifying toys for kids both big and small. Follow me on here to see my latest completed projects or follow me on instagram to see sneak peaks of what's brewing in the workshop!

I wanted to add some speed/torque to this sweet vintage 1989 1st Gen Bigfoot Power Wheels. The original motors are 28 years old and definitely aren't what they once were. I got a few new parts off Amazon and I'm going to make this thing a little faster.

Here's a materials list of what you'll need to complete this project:

2x Traxxas Titan 21t 550-sized motors

2x 10 tooth pinions - (please note: your model may require different tooth count. COUNT YOUR TEETH before ordering pinion gears! )

2x 550-sized Aluminum Heat Sinks (this is for a 2 pack, pretty good deal imo)

DISCLAIMER: YOU ARE MODIFYING THE ELECTRICAL SYSTEM ON A CHILD'S RIDE-ON TOY. IF YOU'RE UNSURE OF ANYTHING, DON'T DO IT. I don't want to hear that you set your kid on fire, seriously.

Step 1: Remove Push Nuts

Start by taking off the wheels. The little black thing in the middle is called a push nut. They suck. You're pretty much guaranteed to break them while taking them off.

Your options to replace them are either threading the axles and using nyloc nuts, using shaft collars or just breaking down and buying new push nuts. Shaft collars are the fastest/easiest way, but they're kind of expensive.

Step 2: Slide Off Wheels and Gear Boxes

The wheels slide right off. Behind them are the black gear boxes, with the motors attached. Disconnect the wires and slide off the gear boxes.

Step 3: Remove the Stock Motor

The two little flathead screws hold the motor into the gear box. Remove those to get your motor out. The 3 philips head screws open the gear box itself. You can look in there if you want, but it's not necessary for this project.

Second picture is a side shot showing the gearbox and the new motor. Your gear box will probably look different, this is a very old example. The newer ones are similar in function, but a little beefier and have different cases.

Third picture shows the motor out, you can see it has a plastic pinion gear on its shaft. That's what connects the motors rotation to the gears in the gear box. Newer models will have metal pinions pressed on. You'll need new pinions either way.

Step 4: Replace Pinion and Reinstall Motor

Making sure the tooth count and diameter line up exactly between new pinion and old. If you use the wrong tooth count, you're going to strip out your gear box. This was a 10 tooth pinion.

The pinion installs by slipping over the shaft on the new motor and locks on with a tiny set screw. I used some blue thread lock to help hold the set screw in place.

Then I reinstalled the new motor into the gear box. Just mesh the gears together and put the two little screws back in.

Step 5: Connect the Wiring

Next I worked on hooking up the wires. Do a test fit first to make sure you have both wheels rotating the same direction. If one is backwards, just switch the wires between terminals.

The new motors have bullet connectors. If you want to be fancy, you could solder female bullet connectors to the vehicle wiring. I'm not fancy, I just stripped the wires, put them into the bullet connectors and crimped the connection. Then I wrapped it in electrical tape. Heat shrink tubes would be slightly more professional.

Step 6: Secure Wiring, Install Heat Sinks

Then I zip tied all the wires securely out of the way before installing the heat sinks. The heat sinks just snap on. They help keep the motors cool during extended driving sessions. Overheated motors can cause several different sorts of failure, so I like to slap heat sinks on whenever I do a motor upgrade.

Step 7: Play!

A couple of finished shots on the bench and it's ready to play!

Test drive proves successful and the kiddo loves it!

I'm always tinkering with making my kids' toys crazier, so if you're interested, Check out my newest projects on Instagram https://www.instagram.com/poppafixit/

Thanks for reading and best of luck with your projects!

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    12 Discussions

    0
    RyanL2299
    RyanL2299

    6 weeks ago

    For longevity, one of the motors should've been a Traxxas 3975R (reverse rotation) and the other the standard 3975. Brushed motors don't like spinning in reverse rotation for extended periods (think it has to do with the angle the brushes are installed). Plus I believe that most brushed motors turn a little faster in forward rotation than they do in reverse (so you probably had one turning a little faster than the other). Not knocking you as I did the exact same thing and one of the motors burned up pretty quickly then the next one went not too much longer after that one since it was doing all the work. Another thing I didn't do was break in the motors. Just pointing these things out for others. There used to be a hot wheels forum a few years back that had a ton of good information in it but don't think it's up and running anymore.

    0
    Louballs123008
    Louballs123008

    3 months ago

    Just got my brother in-laws ‘85 BigFoot, rough condition but going to be restoring the hell out it. Will have to update you on the mods once done, appreciate all the tips and tricks from all your videos

    0
    mustangbosborn
    mustangbosborn

    5 months ago

    I had one in 87. I have been looking for one of these forever. The only one I found was a 93 model with no battery. Which being from 93 it was in pretty good shape. Would you want to sell it in the future?

    0
    ednevs
    ednevs

    1 year ago

    My kids burn up their 12v motors pretty quickly in our hilly/grassy yard. Is it logical to think a 24v motor might be beefier and make it so I'm not replacing motors every 4-6 months? still running on an aftermarket 12v35ah battery...

    0
    allinonehousing
    allinonehousing

    Reply 1 year ago

    I actually just made for my daughter (and ofcourse myself) a 24v 100w moter upgrade, it wasn't easy but didnt cost me anything but time (bec both the kids 12v jeep, and then a few weeks later a 24v electric scooter i found in the garbage), now after having up and running (and the 24v moter is connected to the gear box (to make it slower ) its still way to powerful for kids to be using

    IMG-20190913-WA0000.jpeg
    0
    PoppaFixIt
    PoppaFixIt

    Reply 1 year ago

    Upgrading to a 775 sized motor will provide more torque, but not all gearboxes will accept both sizes of motors. Using a 24v 550 sized motor will cut your top speed in half and won't necessarily provide more torque.

    0
    mmccoy12
    mmccoy12

    1 year ago

    I got one for Christmas in 1987. It was WONDERFUL.
    I upgraded to a go cart I bought at the Oldsmar Flea market in Oldsmar, FL. About 10 miles from my house!!!

    0
    76brandy
    76brandy

    2 years ago

    how fast?

    0
    DIY Hacks and How Tos

    Awesome! I need to do this to my kid's power wheels. How much does it effect the battery life.

    0
    PoppaFixIt
    PoppaFixIt

    Reply 3 years ago

    Battery life should be pretty close to the same as before the mod. Both motors draw 12v, the new motors are just higher quality and more efficient.

    0
    JmsDwh
    JmsDwh

    3 years ago

    That's awesome! How do the new motors compare to the old ones? I've seen other mods where people add a third 6v battery to the car to run the motors at 18v instead of 12. The results look like fun, kids drifting Lightning McQueen around the driveway.

    0
    PoppaFixIt
    PoppaFixIt

    Reply 3 years ago

    The old motors were pretty much shot, so I didn't have a good baseline to compare to. Stock power wheels motors are typically around 15,000 RPM, IIRC the Traxxis are around 21,000 RPM, which should be a~29% increase in speed. These 21 turn motors also have more torque than stock, so they're better in grass and on inclines.

    Since this motor upgrade, I've also added a third 6v battery into the setup, so now it runs 18v high, 6v low. It really scoots pretty good at 18v. 18v is pretty rough on the gearing, so breakage is to be expected. If you want to go 24v or higher, you pretty much need to run a custom electronic speed controller setup (which I hope to do a write up on in the future!)