My Thunder got under an SUV and I was still driving it, in a split second I thought stop or go in between the four tiers. My Thunder was going East and SUV West it was right in between the four tiers until one tier run it over! I never stoped the throttle and only the rear hub broke and a tier, plus some other minor part. But miraculously that's it, now my Thunder is still Rock'n and Rolling! Thes engineering is excellent!