https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 When I had a Newfoundland this wasn't practical (he was 200lbs, but he also didn't want to move fast). With smaller dogs, I've had good luck with it on a little Dahon. Bad knees, so running it out for me; but pedaling works, and not hard to be slow enough to make it interesting for the dog without making it *too* fast ;>