"We used to live in South Auckland and my two eldest children are used to having to put stuff away or it's going to get pinched. Unfortunately, it was just one of those times that it didn't get put in the bike shed.
"I've got accustomed to living in a beautiful, safe neighbourhood. It's the very first thing to be stolen since I've lived in Papamoa, so it's kind of floored me."
Mrs Lang said she was amazed by the response she had received since she posted a photo of the bike on Facebook.
"I spoke to 15-20 people out in the wider community and I would just make a comment about it, and people say, 'Is that the orange bike on Facebook?'," she said.
"The response I've had from the community, that's just blown me away."
Papamoa resident Russel Harris saw the post and contacted Mrs Lang with an offer to buy Callum a new bike.
Yesterday, Mr Harris called to say he had a new bike on hold and wanted to deliver it to Callum last night - unaware it was his birthday.
"That someone is willing to do that for my son has floored me a little bit," Mrs Lang told the Bay of Plenty Times through tears.
Mr Harris said he read about it on Facebook and thought it was "such a despicable act to do to a little boy".
"I just don't think the thieves should win.
"I don't think they should be able to hurt a little boy like this," he said.
"Hopefully, it puts a smile on his face and makes him realise the world's not all bad."
Callum was rapt when he was surprised with his new bike.
"I'm really pleased," said Callum. He couldn't wait to take his bike for a spin regardless of the rain, saying "it's really cool."
