Tyres are turning blue, should I change them?

[Wyvern971]

After a couple of days out on track at Le Mans my tyres have a distinct blue colour on the shoulders front and rear.

There is a fair amount of tread left on them, but I'm slightly concerned.

Should I be thinking about changing them?

 

[Wyvern971]

Thanks all, I don't own tyre warmers........

I'll leave them on for now, but I'll take another set up with me in case

Le Mans is awesome btw, though it's only £279 for 2 days the rest of the costs add up a bit

 

[Wyvern971]

Righto cold pressures are Front 32 Rear 30

I've done a day out at Donington on them, and they are now going to be replaced as there is sod all tread left on the rear now.

As a side note I'll be leaving the SP at home for Mallory and take my 450 SM, and possibly have a go no my sisters 600RR