I bought a Groller too. It arrived in just one day. I gave it a try today on my KTM 390 and it is not quite as easy to use as it looks. It is hard to get the device lined up correctly, even with the KTM's relatively narrow 150mm wide tire. I think that it would have been better if I had ordered the larger model that can accommodate a 240mm tire. That would have made it a lot easier to center the tire on the rollers.
The Groller should only make contact with the edge of the tire when the bike is on the sidestand. BTW, I also ordered the large one. I tried them both out on my Energica. The size really made no difference from what I could tell on my Energica.
Both of mine also came in less than 24 hours after the order (Amazon Prime).
My two other chain bikes are in Reno. The Kaw and the Suzuki, so I have not yet tried either on those.
Perhaps things are different on a KTM.
-Don- Auburn, CA