Tyre question, going blue on edges?

[nzspokes]

Noticed on the edges of my rear tyre there is a dark blue line on the outside edge. Tyres are Pilot Roads. Is it a sign of anything or just something they do?

[Gremlin]

Pic.

Sometimes its actually lack of use. Scrub them in and away goes the blue...

Otherwise it's heat related, you can also have cold shear... anyway, lots of things, pic.

[nzspokes]

Pic.

Sometimes its actually lack of use. Scrub them in and away goes the blue...

Otherwise it's heat related, you can also have cold shear... anyway, lots of things, pic.

How well do you think a picture of a black tyre with a dark blue line will come out at night?

Looks like metal thats had a gas torch on it. Will do a pic tomorrow. Its right out near the edge.

[nzspokes]

Turns out I was wrong. Photo kinda shows it right out the edge. The thin blue line.....

[eldog]

seen this on truck tyres too

[JimO]

................

[sil3nt]

http://biketrackdayshub.com/motorcycle-tyre-wear-guide

Near the bottom

[nzspokes]

http://biketrackdayshub.com/motorcycle-tyre-wear-guide

Near the bottom

Mint. Thanks mate.

[nzspokes]

Tyre Discolouration - Blue Tyres

Motorcycle Blue Tyres

You often see the question come up 'why are my tyres blue' or 'what's this blue stuff on my tyres' with people suggesting that when you see it the tyres are done. This isn't completely true.

What makes it blue? - Motorcycle tyres actually contain oils that keep the tyre soft and the blue/green tint you can see on your tyres is just the oils coming to the surface.

Why are they on the surface? - After the tyres have been used to the point where they gain significant heat, when they cool down again (this is one heat cycle) the oils in the tyre will often come to the surface. When you go back out and ride the bike these surface oils are scrubbed off and it's only when you come back in and let the tyres cool down again that you'll see more oils coming to the surface.

Each time you take a tyre through a heat cycle you are losing the oils that keep the tyre soft, so the more heat cycles a tyre has been through the less effective the rubber is going to be for you.

As a side note, heat cycles will affect track tyres a lot worse than road biased tyres, as road tyres are expected to go through these cycles.

[AllanB]

Just oils in the rubber. PR2's did that on my bike after a good hard hoon.