The 2.5mm framework made from harder graphite product originated for very-high traction conditions, or whenever using tires providing many steering making the automobile more challenging to push. This harder framework makes the automobile more stable and much more easy to use a car, and eliminates oversteering. The framework was in fact redesigned to guide the Tweak-Free Pod System and side braces. The X1'21 framework continues to create a wheelbase modification making use of among three mounting jobs leading suspension system system. On the basis of the installation option, wheelbase are chosen through the standard size or +/- 4mm alternatives. Fits X1'21 #371027 X1'21 Graphite Chassis 2.5mm - Hard