Apparently, Sepp didn't get the bike riding memo.
Some days we would ride and he would run fast for the first 5mins or so, and then drop into a trot. Other days we would start out and he would not move above a trot.
I even went out and bought a Springer bike attachment for him, but he was so slow I was almost dragging him while he was attached to the spring.
Here is a video showing the difference between biking with Seth and Sepp:
I don't know what it is. I haven't tried biking since we[LOL "he" I don't run on it!] started using the treadmill. He can run on that for a solid 10-15 minutes so I KNOW it isn't because he's too tired. Even biking, I know he isn't tired because if we see another dog or a cat, or heaven forbid a feakin' squirrel, he's pulling and running his little heart out.
I pretty much decided he just wasn't/isn't that interested in biking and haven't pushed the issue.
As you can see, Seth LOVES bike riding. He LOVES to pull the bike - he's a total spazz about it and gets uber excited to go. I've considered taking the two of them at the same time. Maybe Seth would give Sepp a little competition, but there's no way I could manage them both without dying.
I guess for now, we'll be sticking to the treadmill. When summer comes around and the weather is better we may try biking again, if not for Seppel's benefit, for Seth's.