I'm on my second pair of Sidis with replaceable soles/treads and while the shoes fit like gloves, the soles/treads wear out quickly and they aren't cheap--$40-50! I've also had a shoe out of each pair have the nut that the screw holding the tread goes into come loose and spin in the shoe. I can't tighten the screw past a certain point and later, I can't get it out either. I think I'm done with Sidis after this. They're too high a price for this to happen.