Supergas for narrow feet: do they shrink?

[CaliforniaDrumming]

Bought a pair of white Supergas. My usual size is an 8, so I bought a 7.5 after reading reviews. But they are still slightly too big and wide. Do they shrink when washed? I will be washing them a lot in the machine as I walk in grubby parts of London.

I've only washed mine once and they didnt shrink...sorry

Thanks! I think they don't really suit narrow feet. Sending them back.