Looks like the chain is going backwards but it's just going really fast.
Chainsaw - Rust
Breakdown of the UV offset for the chain for those interested and also for Erwann Dupont. I hope this helps dude!
Chainsaw - Rust
Chainsaw for rust. This was the first asset I've created using toolbag 3 for the baking process which is actually, really awesome. The chain animates via a uv offset.