This Yikong yk4082 rc crawler is modified:
The ratio of front 6.5 to rear 3.5, using 3s, carbon fiber wheel hub, 3mm thick. Within 3mm it can’t hold up. The tire is HB2.2 with a diameter of 140.
Here is the answer.
This yk4082 rc car can not only climb up but also go down. Maybe it can even climb up backwards. Haha.