found out the answer myself lol lvl 34 at elite four
Aron evolves at level 32.
Do you mean Aron? If so, then it's by level, but I don't know which level.
Your Aron will evolve at level 32 into Lairon.
Aron-->Lairon-->Aggron
You can find Aron only in Diamond.
Aron will most likely evolve at level 23 unless paralyzed
18
30
Aron evolves into Lairon at level 32.
Aron will evolve into Lairon at level 32, then into Aggron at level 42.
Aron evolves at level 32 into lairon .
Aron evolves into Lairon at level 32