I'm looking for a 9 speed chain for my cargo bike. I'm using Putoline and not wanting to oil the outside of the chain to avoid getting oil on my trousers. What chains will be least likely to go rusty? There's the KMC X9 EPT. Does EPT work well? Any others? It needs two chains due to chainstay length so cheaper the better.
12 speed rather than 9 but I used to get a lot of surface rust on Shimano SLX or Deore chains in winter regardless of how how careful I was with washing and lubing, I think down to road salt when the bikes were on the towbar rack. I moved to KMC X12 and it was a lot better. I'd give KMC a go, they are cheap enough to experiment.
I’d use the gold coloured kmc chains - never had one of those (or sram xx1 gold / oil slick - but very spendy and not in 9 speed) rust.
KMC EPT chains? Not used them but claim rust protection. As reviewed by STW
https://www.kmcchain.com/en/series/ept
https://singletrackworld.com/wp-content/uploads/2017/11/review-kmc-x11-ept-anti-rust-chain/
All readily available online eg. https://www.merlincycles.com/kmc-x9-ept-9-speed-chain-269563.html?utm_source=PHG&source=PHG&utm_medium=Affiliates&utm_campaign=genieshopping
IME cheaper ones rust, more expensive ones don't.