I need a new rear tyre to replace the Avon Roadrider, the front still has life left in it. I was looking at the very limited range of 19inch rear tyres and came across the Conti Classic Attack, which is a radial tyre, I think the general consensus is that it is not advisable to mix radial and bias, but is it actually a proven dangerous thing to do? I guess the sensible thing is to not take the chance, maybe wait to change front and rear at the same time, but I would appreciate an expert opinion.