[Dr. Sivana]

I had thought that the rubber on the tires keep the bike from being grounded, making a lightning strike unlikely while in motion.

[semaj]

The Electro magnetic field generated by the wheels might have attracted the bolt. ....or the guy just hadit comin.’

[Red Badger]

Not true. The tires do not protect from a lightning strike.

[Gamecock]

Nope.

The metal of the car protects you. Not the tires.

Source

[NorthMountain]

A few inches of wet rubber are not going to stop a gigavolt electric discharge that made it through a few miles of atmosphere.

[Puppage]

That’s a wives tale.

[DiogenesLamp]

I had thought that the rubber on the tires keep the bike from being grounded, making a lightning strike unlikely while in motion.

When dealing with lightning range voltages, everything is grounded. Rubber contains carbon, and with those voltages, it will blow right through it.

For what it's worth, i've seen a dump truck lift it's bed under some high line wires until it touched them. All the tires exploded, and here we are only talking about 12 kilovolts.

[Pearls Before Swine]

Insulation can be jumped if the voltage potential across it is high enough. That’s why high tension lines have such big insulators. And, the lightning potential is millions of volts. Also, if the tires are damp, the insulating value is greatly reduced.