Gerund or Infinitive

Hi,

I am helping some students with their English work for their teachers, but I am struggling with the verb 'to try'. I understand the rules in theory, but I am struggling with them in practice.

Which is correct in these two examples?

I tried carrying the bag upstairs, but it was too heavy. Can you help me to carry it upstairs?
I tried to carry the bag upstairs, but it was too heavy. Can you help me to carry it upstairs?

OR

I tried repairing the bike but I didn't manage to do it.
I tried to repair the bike but I didn't manage to do it.

Thanks!