These are two very frequently asked questions that I receive on a daily basis when customers enter the store. The difference between the models are very distinctive, aesthetically and in simple practicality purposes. The street version is more desirable for your everyday use in possibly a metropolitan area or for rides in your paved neighborhood. It is equipped with 20"x 2.25 Kenda street tires versus it's counterpart that is equipped 4" wide off road and all-terrain tires. The Fat Tire models are better utilized and can live up to its full potential in more off road conditions and environments. I have taken it out personally along the beach in the deep sand as well as in the snowy white mountains of upstate New Hampshire. Now, with all the debris that accumulates on high traffic roads and on metropolitan bike lanes, I'd say the thinner street tires are more practical. But, if you are looking to access more remote areas like dirt roads, deep sand, gravel, snow etc; the fat tires are designed for just that. Where I live in urban south Florida I preferably use street tires as I sometimes use my e-bike to commute through downtown Fort Lauderdale. As far as the other specifications of the two versions they are exactly the same. Another frequently asked question of the two models and two versions is; what is the difference between the B10 and B20? The very subtle and simple difference is the B10 has a step through bar frame and B20 has the standard straight bar frame.