(Portland, OR)  --  New details are coming to light regarding a car crash that killed Mythbusters star Jessi Combs in Oregon.  The Harney County Sheriff's office report says front wheel failure was responsible for the late August crash in the Alvord Desert.  Investigators say the wheel collapsed after hitting something.  Combs was attempting to break a speed record and was driving at about 550 miles-per-hour when her jet car wrecked and caught fire.