I can see how Sidi width can be a problem, but I have very narrow feet and toes, so I actually prefer them. I'always found the Shimanos to be too wide around the ball of the foot (although it was never a big issue for me) The problem is the length. Officially, the insoles from the Wires should be 2 mm longer than the Shimanos in size 38, but I've just measured the inside of the shoes and the Shimanos are actually 5 mm longer. I'm guessing the Sidi measuring is technically correct, since the insoles also go a bit up on the heel cup, but that didn't help when ordering.