Why Do Race Tyres Turn Blue?

Pirelli Supercorsa SP V3

Many riders who’ve got a few track days or race meetings under their belt will have seen a tyre which looks like it’s started to turn blue.

But what exactly is it that causes a motorcycle tyre to turn blue?

In the September 2016 edition of Fast Bikes, they’ve been speaking to Bridgestone’s Gary Hartshorne to find out more.

There are a lot of oils used in the production of a tyre, and the blue colouring is a sign of those oils rising to the surface of the rubber where it has been worked too hard.

Gary explains:

“You get blue-ing where the tyre’s got too hot, either through ambient temperatures, pressures, surfaces – or all three factors.”

Once the tyre’s temperature drops, it will cure – most keen track day riders and racers will know about heat cycling.

Try sticking your finger nail into the rubber once the tyre has cooled, and it will be harder to push in than before – and you want it to cure as evenly as possible across the tyre to make the most of those heat cycles!