Most efficient method of getting Crobat in Pokémon HG SS?
Solution 1:
There are exactly two ways to get a Crobat:
- Get a Golbat to 220 friendship, then level it up.
- Trade for one.
If it doesn't evovle, then it's not happy enough. The most efficient approach depends on how far you are from the target; if you're very close, then a haircut might do the trick, or a grooming from Daisy.
You also need to take into account which generation you're actually playing: HeartGold and SoulSilver are 4th generation, and use different mechanics.
Assuming that you're really playing HG/SS, as your question title suggests, you can get a lot of friendship points very quickly if you have a steady supply of EV berries and money to burn on vitamins; refer to Bulbapedia for exact numbers. However, this necessarily disrupts any EV training you may have performed, so you have to determine if that approach is worth it.
If you are able to dump your saved game, you can check the current friendship level exactly and plan the best strategy based on how far you have to go; you can also approximate the friendship level; the NPC in Goldenrod City near the bike shop is probably the most easily accessible one.
Solution 2:
You can only evolve Golbat into Crobat you need level his happiness (Friendship) independent of your Generation (besides the first), but as @MichaelMadsen pointed in his answer, you can get a Crobat in a trade.
- How you can level the friendship in GenII.
- How you can level the friendship in GenIV.
GenII
- Gold
- Silver
- Crystal
GenIV
- Diamond
- Pearl
- Platinum
- HeartGold
- SoulSilver
Why my Golbat is not evolving in Crobat, even with high happiness
- Check if your Golbat is holding an Everstone
- Your happiness may not be as high as you think. remember, you lose happiness every time you let your pokemon die, put him in the PC, etc (check the How you can level the friendship link above).
Solution 3:
Generally when the NPC In Goldenrod say "I've got the feeling your Pokemon really trusts you" You're at that stage where you can level it to 25 and it will evolve, I had my Zubat since level 2 and i just finished the 4th gym. It's had a sooth bell since before the third gym when I picked it up in the National Park.