Answers.Body: <p>There are a number of <a href="http://www.bricklink.com/catalogItem.asp?P=motor1pb01">pull-back motors</a> for system wheels.  Look through the <a href="http://www.bricklink.com/catalogList.asp?catType=P&amp;catString=504">Motor, non-electric</a> section of bricklink. There is even one <a href="http://www.bricklink.com/catalogItemIn.asp?P=5313a&amp;in=S">rechargeable electric motor</a>.</p>
  
  <p>There was also an <a href="http://www.bricklink.com/catalogItem.asp?P=4288">all-rubber tire</a> with an axle hole in some of the old space sets, though that may have a rounder shape than you're looking for.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-02T03:06:50.873Z
Answers.LastActivityDate: 2011-11-02T13:39:55.423Z
Answers.LastEditDate: 2011-11-02T13:39:55.423Z
Answers.UserDisplayName: retracile
Answers.Body: <p>Ever since this question was asked I wanted to build something that would fit that scale.  Here's the result:</p>
  
  <p><img src="https://i.sstatic.net/YGGMJ.jpg" alt="enter image description here"></p>
  
  <p>I know this is not using only LEGO pieces but, I thought that there was no way to make the LEGO motors fit 'inside' a normal looking LEGO City vehicle. So, this is basically a homemade motorized brick made of a 2x2 brick glued to the 2x2 wheels-brick.  I then gutted out the insides to make place for all the electronics.</p>
  
  <p>It's controlled by an ATtiny chip (similar to the Arduino chip) and uses a 3.3V LIPO battery.  The motor is a small 'pager motor' that I got from an old toy.  The chip is programmable and can run the motor at different speed.  I'm pretty sure I could figure out a way to make a steering mechanism to go with it and, if I go really crazy, a BlueTooth brick to remote control it...  </p>
  
  <p>You can see it in more details in <a href="http://youtu.be/-lGYuBtvXLc" rel="noreferrer">this video</a>, see it run in <a href="http://youtu.be/2bWc3iCIV-w" rel="noreferrer">this video</a> and I have more pictures on my <a href="http://phillipecantin.blogspot.ca/2012/12/legotiny.html" rel="noreferrer">blog</a>.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2012-12-30T02:34:32.437Z
Answers.Text: +1 I was just about to edit what I thought was a typo until I looked it up. You really did mean it's a ATtiny chip. :)
Answers.UserDisplayName: Major Stackings
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2012-12-30T13:16:15.000Z
Answers.Text: In this case, an ATtiny13.  I love working with this chip.  I'm going to get some surface mounted ones to make even smaller projects.
Answers.UserDisplayName: pcantin
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2012-12-23T20:48:22.847Z
Answers.LastActivityDate: 2012-12-30T13:24:30.957Z
Answers.LastEditDate: 2012-12-30T13:24:30.957Z
Answers.UserDisplayName: pcantin
Answers.Body: <p>Most vehicles in modern city sets use wheels with <a href="http://www.bricklink.com/catalogItem.asp?P=60700">∅20×12 mm tires</a>. Such tire can be put on <a href="http://www.bricklink.com/catalogItem.asp?P=32270">12 tooth double bevel gear</a> or combination of narrower <a href="http://www.bricklink.com/catalogItem.asp?P=42610">∅11×8 mm wheel</a> and <a href="http://www.bricklink.com/catalogItem.asp?P=6589">12 tooth bevel gear</a> to connect with axle. The only problem I see with this solution is that tires are swollen a bit by gear so they are not freely turned when covered with <a href="http://www.bricklink.com/catalogItem.asp?P=50745">mudguard with arch</a>.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2017-12-09T16:19:18.693Z
Answers.Text: It would be nice to see a picture of this setup.
Answers.UserDisplayName: EJ Mak
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-11-03T13:09:27.420Z
Answers.LastActivityDate: 2011-11-03T13:09:27.420Z
Answers.UserDisplayName: Denis Otkidach
Answers.Body: <p>You could try connecting your wheels using the <a href="http://www.bricklink.com/catalogItem.asp?P=43093" rel="nofollow noreferrer">friction pin/axle</a></p>
  
  <p><img src="https://i.sstatic.net/LS7u0.jpg" alt="enter image description here"></p>
  
  <p>This provides some friction to the wheel hub while also giving the motor an axle to turn. It won't work if there is too much resistance, but for small setups it might be okay and it will fit in all the existing pin-connected wheels. If you're feeling crazy, you could always glue the axle into the wheel hub, or use a bar piece jammed into the pin to increase the friction. Not that I would recommend such techniques!</p>
  
  <p>There are also some wheels that are turned by axles, such as <a href="http://www.bricklink.com/catalogItem.asp?P=55982c02" rel="nofollow noreferrer">this one</a>. In fact, on <a href="http://www.bricklink.com/catalogList.asp?catType=P&amp;catString=532" rel="nofollow noreferrer">this page</a> you can see many wheel/tire assemblies that Lego has shipped, and there are lots where the wheel hub is connected with an axle. Any of these can be easily motorized, though not all of them will be small enough for 6-wide city scale.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-08-25T16:27:57.203Z
Answers.LastActivityDate: 2014-08-25T16:27:57.203Z
Answers.UserDisplayName: Mr. Shiny and New 安宇
Answers.Body: <p>If i remember right, the tires of the small LEGO City wheels fit perfectly on a <a href="http://www.bricklink.com/catalogItem.asp?P=4265c" rel="noreferrer">Technic 1/2 bush</a> which then gives you an axle hole, but note that this is very flat on the ground. I don't know if its high enough to add a very <a href="http://www.bricklink.com/catalogItem.asp?P=3647" rel="noreferrer">small gear</a> and build up the connection to your motor.</p>
  
  <p><img src="https://i.sstatic.net/10nIz.jpg" alt="small city wheel"></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2013-01-31T22:54:44.143Z
Answers.Text: @Pubby You know they do make LEGO technic belts.
Answers.UserDisplayName: J. Walker
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-10-26T12:29:32.593Z
Answers.Text: 4 studs wide seems not enough to put motor or clockwork. I meant 6 studs used in trucks, buses, SUV: they use large wheels. But this is useful info anyway.
Answers.UserDisplayName: Denis Otkidach
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-10-26T12:52:23.043Z
Answers.Text: if you use the 1/2 bush and add an axle on your own, you can build your vehicle as while as you like - just depends on the axle you're using.
Answers.UserDisplayName: oezi
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-10-27T10:23:52.233Z
Answers.Text: If a gear doesn't fit, a rubber band belt would.
Answers.UserDisplayName: Pubby
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2011-10-26T12:11:54.750Z
Answers.LastActivityDate: 2011-11-27T17:44:19.897Z
Answers.LastEditDate: 2011-11-27T17:44:19.897Z
Answers.UserDisplayName: oezi
Body: <p>I'd like to build city-scale (6 studs wide) vehicles motorized with either PF motor or clockwork. The primary problem right now is connecting wheel(s) to motor. Are there small enough LEGO wheels with axle hole? Any other idea on how to connect it to motor (with gears, friction, or by any other means)?</p>
  
Tags: <power-functions><city><vehicle>
Title: How can I motorize City-scale wheels?
UserDisplayName: Denis Otkidach
ThreadText: # How can I motorize City-scale wheels?
  
  (Asked by: username_0 on 2011-10-26)
  
  I'd like to build city-scale (6 studs wide) vehicles motorized with either PF motor or clockwork. The primary problem right now is connecting wheel(s) to motor. Are there small enough LEGO wheels with axle hole? Any other idea on how to connect it to motor (with gears, friction, or by any other means)?
  
  **Tags:** power-functions, city, vehicle
  
  
  ---
  
  ## 5 answers
  
  ### Answer by username_6 on 2011-10-26. Score: 13 | Accepted answer
  
  If i remember right, the tires of the small LEGO City wheels fit perfectly on a [Technic 1/2 bush](http://www.bricklink.com/catalogItem.asp?P=4265c) which then gives you an axle hole, but note that this is very flat on the ground. I don't know if its high enough to add a very [small gear](http://www.bricklink.com/catalogItem.asp?P=3647) and build up the connection to your motor.
  
  ![small city wheel](https://i.sstatic.net/10nIz.jpg)
  
  > **Comments:**
  > **username_0**: 4 studs wide seems not enough to put motor or clockwork. I meant 6 studs used in trucks, buses, SUV: they use large wheels. But this is useful info anyway.  
  > **username_6**: if you use the 1/2 bush and add an axle on your own, you can build your vehicle as while as you like - just depends on the axle you're using.  
  > **username_8**: If a gear doesn't fit, a rubber band belt would.  
  > **username_7**: @username_8 You know they do make LEGO technic belts.  
  
  ---
  
  ### Answer by username_1 on 2011-11-02. Score: 11
  
  There are a number of [pull-back motors](http://www.bricklink.com/catalogItem.asp?P=motor1pb01) for system wheels. Look through the [Motor, non-electric](http://www.bricklink.com/catalogList.asp?catType=P&catString=504) section of bricklink. There is even one [rechargeable electric motor](http://www.bricklink.com/catalogItemIn.asp?P=5313a&in=S).
  
  There was also an [all-rubber tire](http://www.bricklink.com/catalogItem.asp?P=4288) with an axle hole in some of the old space sets, though that may have a rounder shape than you're looking for.
  
  
  ---
  
  ### Answer by username_2 on 2012-12-23. Score: 11
  
  Ever since this question was asked I wanted to build something that would fit that scale. Here's the result:
  
  ![enter image description here](https://i.sstatic.net/YGGMJ.jpg)
  
  I know this is not using only LEGO pieces but, I thought that there was no way to make the LEGO motors fit 'inside' a normal looking LEGO City vehicle. So, this is basically a homemade motorized brick made of a 2x2 brick glued to the 2x2 wheels-brick. I then gutted out the insides to make place for all the electronics.
  
  It's controlled by an ATtiny chip (similar to the Arduino chip) and uses a 3.3V LIPO battery. The motor is a small 'pager motor' that I got from an old toy. The chip is programmable and can run the motor at different speed. I'm pretty sure I could figure out a way to make a steering mechanism to go with it and, if I go really crazy, a BlueTooth brick to remote control it...
  
  You can see it in more details in [this video](http://youtu.be/-lGYuBtvXLc), see it run in [this video](http://youtu.be/2bWc3iCIV-w) and I have more pictures on my [blog](http://phillipecantin.blogspot.ca/2012/12/legotiny.html).
  
  > **Comments:**
  > **username_3**: +1 I was just about to edit what I thought was a typo until I looked it up. You really did mean it's a ATtiny chip. :)  
  > **username_2**: In this case, an ATtiny13.  I love working with this chip.  I'm going to get some surface mounted ones to make even smaller projects.  
  
  ---
  
  ### Answer by username_0 on 2011-11-03. Score: 6
  
  Most vehicles in modern city sets use wheels with [∅20×12 mm tires](http://www.bricklink.com/catalogItem.asp?P=60700). Such tire can be put on [12 tooth double bevel gear](http://www.bricklink.com/catalogItem.asp?P=32270) or combination of narrower [∅11×8 mm wheel](http://www.bricklink.com/catalogItem.asp?P=42610) and [12 tooth bevel gear](http://www.bricklink.com/catalogItem.asp?P=6589) to connect with axle. The only problem I see with this solution is that tires are swollen a bit by gear so they are not freely turned when covered with [mudguard with arch](http://www.bricklink.com/catalogItem.asp?P=50745).
  
  > **Comments:**
  > **username_4**: It would be nice to see a picture of this setup.  
  
  ---
  
  ### Answer by username_5 on 2014-08-25. Score: 0
  
  You could try connecting your wheels using the [friction pin/axle](http://www.bricklink.com/catalogItem.asp?P=43093)
  
  ![enter image description here](https://i.sstatic.net/LS7u0.jpg)
  
  This provides some friction to the wheel hub while also giving the motor an axle to turn. It won't work if there is too much resistance, but for small setups it might be okay and it will fit in all the existing pin-connected wheels. If you're feeling crazy, you could always glue the axle into the wheel hub, or use a bar piece jammed into the pin to increase the friction. Not that I would recommend such techniques!
  
  There are also some wheels that are turned by axles, such as [this one](http://www.bricklink.com/catalogItem.asp?P=55982c02). In fact, on [this page](http://www.bricklink.com/catalogList.asp?catType=P&catString=532) you can see many wheel/tire assemblies that Lego has shipped, and there are lots where the wheel hub is connected with an axle. Any of these can be easily motorized, though not all of them will be small enough for 6-wide city scale.
  
  
  ---
  
  