I firmly believe that to maintain correct and best running temp you need to use the correct speed rated tyre. I only do road and the odd trackday though. I am sure the decent racers can keep the stiffer tyres up to temp.
When you put new GPRs on the bike they feel like a good pair of trainers. When I have used Z rated tyres they feel more like your best shoes
Not exactly the type of feedback rossi would give burgess but it's the best I can explain lol
Tyres come down to a lot of personal preference as well of course.
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