Originally Posted by Searider
Be careful with stainless on galvanised.
The galvanising in contact with the stainless will corrode quite quickly, leaving the underlying steel open to the elements - causing rust staining.
We see it all the time with galvanised chain shackled to a galvanised anchor with a stainless shackle.
The OP was asking about galvanised washers v stainless washers on a trailer. I've replaced all the rusty galvanised washers on my trailer with stainless ones. No rust anywhere after several years.
My experience of galvanised washers from the day job is that the galvanising process on such relatively small, low value, high volume parts is that it's variable at best and p$ss poor at worst