The black mountain bike trails in Va d'Isere bike park are split into two categories - Expert & Elite, and they're only to be ridden by the most competent of bikers, with the skills to handle them.
You need to head over to the Tignes side of the mountain if you really want to test yourself on some of the hardest MTB tracks.
Black Trails - Advanced / expert
Karmasutrail is the longest of the black trails at 3km long with a drop of 340m. Start: Top of Toviere Finish: on Gypsy red trail.
Black Metal. Very steep, very loose full-on descent - strictly for expert level riders. Distance: 1km & descends 250m. Start: Top of Aeroski. Finish: Rosset
Moustache A very tough black trail, with steep narrow & very technical sections which links onto Black Metal. 1km & descends 250m. Start: Top of Aeroski. Finish top of Black Metal.
Double Black trail - Elite
Scarefresse. The only Elite graded track in resort, and as the name suggests its hard as nails. Start from part way down the Taretaise Airline blue trail and finish above Val Claret, rejoining the red or blue trails back to the village. Expect huge gap jumps and really technical riding.