snowblower-tire studs

[fatlazyless]

Recently upgraded to a big 8hp, old, Toro sno-blower for all of $130, used. It has large smooth tires pre-drilled for studs. Why can't I just screw stainless, hex head, sheet metal screws into the tire holes. Anyone know about these tires....like how deep are the pre-drilled holes? Obviously do not want to ruin the tires.

Sno-blower tire chains from www.tirechains.com are out of my price range!