purple/pink spots on a tire tread

[Victor Kan]

When I looked at my road bike's rear tire (a Specialized Turbo Sport
60tpi slick with maybe 2500 miles on it, maybe half of that as a front
tire) this morning,there seemed to be some purple/pink (maybe magenta?
spots all over the flattened wear area of the tread.

At first I thought that I maybe rode through somebody's chewing gum or
some paint. But my front tire has no such spots and the spots don't
seem lumpy or sticky as I'd expect chewing gum to be.

Those colored spots don't otherwise look or feel much different (maybe
more flexy, but still rubbery) from the surrounding black tread, but
I'm wondering what the heck it is.

Is this a wear indicator embedded in the tread? Is this the "Flak
Jacket" puncture prevention layer showing through? I'm thinking that
despite the common advice to ride a tire until the casing shows
through, maybe this layer doesn't have the grip of the normal, black
tread and it's about time I replaced it?

 

[Michael Warner]

On 18 Jul 2006 09:25:08 -0700, Victor Kan wrote:

> When I looked at my road bike's rear tire (a Specialized Turbo Sport
> 60tpi slick with maybe 2500 miles on it, maybe half of that as a front
> tire) this morning,there seemed to be some purple/pink (maybe magenta?
> spots all over the flattened wear area of the tread.
>
> At first I thought that I maybe rode through somebody's chewing gum or
> some paint. But my front tire has no such spots and the spots don't
> seem lumpy or sticky as I'd expect chewing gum to be.
>
> Those colored spots don't otherwise look or feel much different (maybe
> more flexy, but still rubbery) from the surrounding black tread, but
> I'm wondering what the heck it is.

Maybe some poor Asian worker's finger got caught in the rubber mixer
and ripped off, and they didn't bother trying to fish it out.

--
Home page: http://members.westnet.com.au/mvw

 

[amakyonin]

Victor Kan wrote:
> When I looked at my road bike's rear tire (a Specialized Turbo Sport
> 60tpi slick with maybe 2500 miles on it, maybe half of that as a front
> tire) this morning,there seemed to be some purple/pink (maybe magenta?
> spots all over the flattened wear area of the tread.
>

This is the wear indicator. The purple layer is fairly thick so you can
still run on it for a while before you need to replace the tire. The
current mondo pro tires are the nearest equivalent to the turbos and
they don't have this feature so you end up wearing them to the cords
anyway.