We did road race with DEM’s. We had 4.50×10’s on the front and 7.10×11’s on the rear. The fronts were good but the rears wore down fast. We were not the only kart this happened to. Back when there were DCM’s, they would last us for a three day weekend. We ate up a set of DEM’s in a day.
I have a set of unused DEM rears if you’re interested.