Why we don't ride over things with holes.

As a rule of thumb I don't ride over anything that has a hole under it.

To each their own but I tend to not drive over anything that has a hole underneath it. Grates, man hole covers, wood or anything else that is used to cover a hole can break or come loose. This picture represents a worse case scenario but you could damage your rims or bike or possibly get thrown off especially if traveling at speed. My advice would be to avoid driving over any of these coverings unless absolutely necessary.