Hey guys, so my gf just bought herself a single speed bike and it's great because now we get to bike together more often now.
Question is though, she wants to take her 1yr old sister along as well (not all the time but she would like to take her on several of our rides and if we do take her it would be on designated bike paths and not on the street). Would it be safe to mount a rear seat onto her bike frame? Meaning we would have to drill into the frame to bolt on the seat. She has thought about getting a trailer hitch but feels that the rear seat would suit her best because she would have her close to her at all times. Her bike is made out of steel if that makes a difference. We're just worried that drilling into the frame would weaken it and put the baby at risk.