svt4stv - i dont know anything about wal-marts helmets. but what i do know is motorcycle helmets are NOT the same as automotive helmets.
i went to a motorcycle shop to get a helmet for a auto-x event thinking that a motorcycle helmet would be fine; i was wrong. i cant remember the explaination, but because a motorcycle helmet is more ridgid it could actually do more harm them good in a vehicle.
track's require certain types of helmets, the SNELL rating is the standard for automotive use. some track's don't care what you use, others can be strict about it. worst comes to worse you may buy a cheap motorcycle helmet and a track might let you use it, but if you ever wanted to use it again somewhere else you may find that you are not eligable to use it.
my helmet is a Pyrotect open face (my personal preference) w/ a snell rating SA2000 (i think the A is for automotive) DOT that cost's $100 that is high quality that i can use at any track cost to coast.
