This was the first time I was ever able to get my head around it and finally understand over/understeer.
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A fun and safe experiment you can try to demonstrate this: at the grocery store take an empty cart and put a case of soda on the rack under the basket. First, put it directly over the front wheels and push the cart around the store. This will somewhat demonstrate understeer. Now push the soda to the back, closer to the rear wheels. This will demonstrate, to a degree, oversteer.
.
A fun and safe experiment you can try to demonstrate this: at the grocery store take an empty cart and put a case of soda on the rack under the basket. First, put it directly over the front wheels and push the cart around the store. This will somewhat demonstrate understeer. Now push the soda to the back, closer to the rear wheels. This will demonstrate, to a degree, oversteer.