I always used a Flexi lead to run my small dogs, with a bike. Emma never really loved it. She has some big issues, so she isn't allowed to run like that, any more. Teenie *loved* it, but she would run her pads off, even in the grass, so I had to stop, with her. One of these days, I'll have a big, powerful dog that needs to run, and I'll start biking, again. I do loooove going out with a dog.