Should i main jg or support for climbing in ranked?

Jungle if you play a champion that both clears camps fast, and ganks HARD. Ideally you want high damage, cc, and mobility to close gaps quickly so positioning is less of a bitch.

Good example: Kayn. High damage, mobility, and a knock up to secure kills

Flawed Example: Udyr, Amazing damage, and decent cc, but you have to position yourself to gank effectively and you have less freedom and less time to make plays because you are running up to your target.

Granted, there's more than just clearing and ganking, some junglers are better at securing objectives and winning the long game, but lets face it, you're trying to climb. If you don't gank, your lanes will suffer, they will blame you, you will hate them, and it's all going to go to shit real fast. Most lower elo players cannot fathom playing defensive or safely and underestimate the value of simply not feeding, even if they aren't getting kills, so make sure you're able to clear fast and gank CONSTANTLY.

Jungle has more impact then Support.

I'd say support because Jungle is very difficult and you don't have to focus on CSing on support. I made it from silver 4 to gold 5 in like 60 games on Lulu support.

Jungling is easiest as you have access to all lanes and the important smite to secure objectives