Sarah’s found a solution that works for her and her daughter:
We have purchased a bike lock for our 6 year old daughter and were concerned about remembering the four-digit combination. In a fit of genius I wrote the number in her school folder that she brings to and from school every day. This way she and her accompanying adult always have it, but no one else does. It worked for us this morning when we couldn’t remember it!
Sarah’s hack wouldn’t work for my son as his bike riding is more likely to happen on weekends when there are no school folders in sight. Assuming the helmet doesn’t get locked up with the bike, how about a small adhesive label inside the helmet with the combo written down?
Any other ideas, Parenthackers?