I have had no problems with my take off premounts because my premounts come on Speedmind wheels!
The newer takeoff mounted that come from Schumacher are pretty horrible.They are too stiff which is probably causing part of the problem.If your hobbyshop is smart the will by the ones that come from Speedmind/magma.
Sorex tires are great,but after a couple runs they fall off much faster then the Takeoff's.So for the money,I would go with the premounts anyday.On a low bight track 22's or 27's are the way to go depending on outside temps.32's would eve work.