HELL ON WHEELS STEEPLECHASE 2015 | PHOTOS HEIDI ZUMBRUN

There's an almost timeless ease about Heidi Zumbrun's images from last weekend's Hell on Wheels Steeplechase ... dirt stalwarts carrying on a tradition combining motocross and TT racing ... is it 1970 ... or present day? Doesn't matter ... it's rider against machine, against the elements.

Competitors hit Glen Helen Raceway's Trophy Truck Track, March 21, in six classes -- Vintage MX pre 74, Modern MX 1980+, Open Twins, Bomber 75-80 and dual sport, Mini bikes up to 100cc and Ladies open -- on a course featuring sweeping turns, tabletops and wide open action.

Zumbrun's complete gallery: