You'd think that's the case.If you were to weld on the outside of the race that would be the case. But because you are heating the inside of the ring it makes the inside hole contract not expand pulling it away from the hub. Was in a garage that was about 30 degrees rotor same temp and it still worked like a charm. it actually almost fell out when I flipped it over. And Yes I've never seen another rotor where there was no lip at all on the race. That's why I figured if it didn't work I'd be buying another rotor anyway. So it saved me 70 buck. Lol to spend on another rotor because the race ate the rotor on the other wheel. Believe me I gave My friend the OK... look too when he said to weld it.

 

Did not see anyone mention using the high temp grease for a caliper set up considering they run so much hotter than a drum set up. If you put "regular" wheel bearing grease in a rotor they won't last long ( the bearings )! This what I have always used when doing disc brake rebuilds.
http://www.pennzoil.com/other-car-pr...7l-red-grease/