It's because in the old style, the axles had very little margin to rotate. This isn't a problem on older Intamin rides since those don't change direction that fast, but with EGF they chose to implement articulating front cars, which have been used on every Intamin ride since. They changed it pretty quick after opening.
http://rcdb.com/m/nl/977.htm?p=6910 http://rcdb.com/m/nl/977.htm?p=3793
You can see the problem quite easily in NoLimits when you use the Intamin style, on quick direction changes the axle just raises through the surface.