The new solid tracks can't be driven by regular Technic gears; instead, they use special sprocket wheels. There are two options: a big wheel and a small one (both shown in Figure 16-10). The big sprocket wheel can have up to 10 links wrapped around it, is almost 2 studs thick, and comes primarily in yellow, with orange and black avaible, too. The small one can have up to 6 links wrapped around it, is 1 stud thick, and comes in black and pearl grey.