/noticias.info/ At a track where brakes are a primary concern, it has been a left-front wheel locking up that has been a persistent problem for the No. 55 NAPA team at Martinsville Speedway. Waltrip's top lap speed during two Saturday practice sessions was 93.074 mph.
Watch Michael Waltrip work his way to the front during the DirecTV 500 Sunday at 1:30 p.m. ET on FOX.
