CHAPTER 19 ■ WHEELS
Although LEGO no longer sells these particular wheels, there are plenty of other sources. If you don’t
happen to have these wheels in your personal collection, you can find them online on auction sites.
BrickLink.com is a fantastic source for all LEGO parts. For example, Sandwich’s tire and hub can be
found for less than a dollar from over 500 sellers. You can search by part number or description. (Note that
BrickLink sometimes uses the term “tyre” instead of “tire” and that part #6594 also matches a Gas Transit set.)
BrickLink’s sellers are independent and worldwide. So, you’ll want to pay attention to reputation and
location. You should try to purchase as many items as possible from the same seller to optimize the shipping cost.
Alternative Choices of Wheels for Sandwich
Recall that, besides wheel diameter, the other option for controlling speed is battery voltage. Larger diameter
wheels can be installed on Sandwich if a battery voltage less than 9 V is chosen.
Compensating for Larger Wheels with Lower Voltage Batteries
LEGO rim #32057 and tire #32076 meet nearly all of the base characteristics for line following, although they
have a slightly grooved tread design (see Figure 19-13).
Part Number Description
8516 RoboRiders The Boss
8520 Millennium/Millennia Throwbot
9719 Robotics Invention System 1.0
9747 Robotics Invention System 1.5
9794 Team Challenge Set
Table 19-1. (continued)
Figure 19-13. Sandwich’s brother with larger diameter wheels and 6 V battery pack
The wheel has a diameter of 7 cm. The circumference can either be measured, or it can be calculated by
the following formula:
p × diameter = circumference
3.1416 × 7 cm = 22 cm