Perhaps I recieved a defective model, but ime these straps are low quality.
I've been riding a pair for 3 months top now, and the straps are incredibley scuffed and broken apart. One of the straps is largely delaminated; The other is COMPLETELY delaminated and was held together by e-tape.
I recently switched to nylon straps, trashed the old cinelli straps and kept the buttons for use on new nylon ones. I can pull them very tight, they stay tight and hopefully they will last longer.
Once again IME terrific waste of money. Use typical nylon straps until you're ready to drop $$$ for quality singles or perhaps doubles ala mks/toshi/kashimax ect.
BTW currently in the process of making DIY toe strap doublers.. using 2xnylon strap and cordura(nylon) fabric for strap doubler and sewing machine.
Although ultimately I would like to settle with a super quality single strap ala mks/toshi/kashimax (once again), becuase while they lasted, that suede leather sure felt pretty good...