| Didn't see this post until late, but here's what I (think) I know .... bits and bobs in no particular order:
Sticky tyres don't "stick", they are softer so the contact surface deforms better to the contours/inperfections of the road surface and so the contact area is greater (or better).
Tyres deform better at their optimum temperature, which you are unlikely to acheive on the road (unless you are breaking the law!). Hey .. could be an argument for allowing bikes to break speed limits, it'll make the tyres work better and therefore be safer? OK, maybe not a good argument.
As the wheel rotates, the tyre deforms and so the contact patch must slide, which creates friction and therefore heat.
Even on a track it is entirely possible to heat up one side of a tyre and not the other. Common problem that is highlighted in trackday briefings - "not many left handers on the circuit so the left side of your tyre will not get so hot". Something that I forget all about on the road, but then the tyre is not getting very hot on the road (usually).
Lowering the tyre pressure causes the tyre to deform better, so creating more friction and greater heat. Ian's tyre picture looks like it's getting sticky like chewing gum, which is an indication that it is starting to overheat. I suspect that if that is done on the road then the tyre pressure may have been low.
Tyres are an important part of the suspension system. Therefore it is clear that the tyre pressure has an effect on how the bike holds over surface inperfections. If the suspension is too hard then all the works is done by the tyre and you will wear the tyre out MUCH quicker.
Leave your tyre pressure too low when the road is wet and you might be riding on a "slick". As the pressure is lowered the tread pattern closes up until the tyre is a slick. (another trackday briefing warning - cheers WJB).  |