They are not really safe for any kart, I've got a stack of them that I've removed, most are in terrible condition at the time of removing. Relying on those wheels puts your own safety, or the safety of the rider at risk, I wouldn't run them on anything motorized. I know at $3.99 each with the right coupon they are tempting, but I've always done my best to not get into a wreck on my karts, even with quality wheels I've failed twice and rolled them hard, but it wasn't with the added risk of light duty wheels. Ultimately the choice is yours, but I have no income and I'd still make every effort for stronger wheels.