There's already a dozens or so threads on "the dark side." You might want to check them out. It's going to depend who answers you question. Dark siders will tell you it's wonderful, those that use motorcycle tires will tell you it's dangerous. The only advantage I see to using a car tire on a motorcycle is tire mileage. You'll get about 3X the tire mileage, 45-60K miles, I guess. I get 16-18k on AVONs. I won't do it for safety reasons. I've followed 2 dark siders, when cornering the tire rides up on the narrow outside edge. Watching them, it looks to me like a little sand or whatever & you're a goner. I don't think dealerships will put a car tire on a motorcycle, I don't know of any MC shops, in my area, that will either, for legal reasons. I've "heard" that insurance co.'s have refused to pay for damage if you run a car tire. Check out all the other threads on treads.