Fluid, fan and good friction trainers (like 1-up trainers), don't have adjustments on the unit, their resistance is progressive with rear wheel speed, and increases "exponentially" to mimic air resistance as you shift to larger gears. I used to have a blackburn mag trainer that had a way to adjust resistance in 5 different settings from easy to hard(er). The resistance for mag trainers increases linearly and basically the adjustments just steepen the slope of the linear progression of resistance. Anyway very few mag trainers can match the resistance that is provided by fluid or the 1-up trainers at high rotational speed. I would basically spin out my blackburn even at the highest resistance settings while in midseason form.