Quote:
Originally Posted by jkv45
I totally disagree.
Old tires slide quicker, but are not necessarily more predictable than a newer/stickier tire. An old tire i going to lock quicker during hard braking than a newer/stickier tire - and that's not an advantage or safer.
Tires have different characteristics at the limit, but I don't think you can say absolutely that an old tire is more predictable.
You could easily lose the front, and go down, with an old tire where you would have been totally fine with a new tire with more traction.
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Compare the bell-curve groupings of these tyre. Sure there may be outlier examples that don't fit the curves, but most will fit. And predictability is matter of experience and practice. I can say you shouldn't go outside when it's raining because you
might get hit by lightning. But if you combine large sampling sizes of lot s of people in lots of storms, there's pattern that will develop and any one individual can expect to fit in bell curve.
I used 8 different sets of tyres at 48 trackdays last year on two wildly different bikes; 30-bhp 250R and 120-bhp CBR600RR. Tyre ranged from 8-yr old BT-45s to super sticky Alpha 13-SP that you can't even buy. I'd swap wheels between sessions for back-to-back comparisons. They all fit those general characteristics; old street tyres slid sooner at slower speeds and were easier to control at the limits, can even bring back after sliding.
The stickier tyres had great grip with higher limits, but were much more difficult to control. I had to approach their limits much slower, maybe just +1-2% faster each lap. Going over their limits was much more unpredictable than street tyres; sometimes they'd chirp before sliding, most times not. Bringing them back was much more difficult due to limited warning. In fact, the two times I crashed last year were on sticky tyres 1 on Dunlop and 1 on Pirelli, both with no sounds or sliding. Just fine one moment and the next I was on ground.
I consulted with my friend & coach who raced TZ250s professionally in AMA back in '90s. He said yep, that's how sticky tyres work. The higher the limit of grip, the more knife-edged the behavior. Like starting out racing on small bikes teaches you finesse and cornering speed, starting on street tyres teaches you how to feel for the limits of adhesion. Knowing when you're getting close and balancing steering & throttle to not go over.
After my 2nd crash, he suggested i go back to street tyres. I gradually improved my speeds and times well beyond what I was able to previously do with race tyres. I could hold throttle on for more time on track, all the way through turns with both tyres sliding. After learning how to find limits of street tyres, moving up to stickier tyres was easier this time because I had learned how to feel for limits and how to control them at their limits. Things happen a lot faster with sticky tyres and require much faster reflexes and response.
If you lose front-end on street tyre, you didn't catch HUGE warning signals. If you had been on stickier tyres, you most certainly 100% will have crashed as well in identical situation because the signals are way, way smaller and much more subtle.