PR2 question

[Ohendo]

Finished what turned out to be an amazing evening ride last night, and noticed these lines running along the tires.

Lines are there on both front and rear, not quite in the center of the tire. I can feel them if I run a finger nail across perpendicular to the line. They go all the way around.

The front's been on since October '13, rear mounted last month. Is this just something from the manufacturing process? Sounds odd to me since they're off center. This is my second set of PR2's and don't remember seeing the line on the first set.

Any ideas? Anyone with PR2's have these lines?


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[Ohendo]

After checking out some pics online, guess it's the leftover from whatever the green line is on a brand new tire like this:

I always thought that colored line was just ink or paint. Maybe some kind of sealant?


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[motojoe122]

Double check this, but I thought it was a graphite line to dissipate static electricity built up from rolling on the ground. My PR2's have the same thing.

Found this searching the web...
Pilot Power/Pilot Road Technical Information

Anti Static strip

When a motorcycle is in use there is a build up of static within the machine. It is necessary to ensure that this is dispersed during usage.
In order to facilitate this there is a carbon black strip built into the tyre during manufacture. This strip is moulded into the tyre before curing using carbon, as this is a good conductor of static electricity. This strip is practically invisible on a new tyre, but can appear as the tyre wears, especially if the usage of the motorcycle is not high. There is no detrimental effect on the performance of the tyre either before, during or after this strip has become apparent. The positioning of this groove is slightly ‘off centre’ and can be seen in the diagram below.

 

[Ohendo]

Looks like you nailed it! Found this post from a Michelin tech (supposedly) in some forum on google when searching the terms "Michelin PR2 Construction":

Anti Static strip

When a motorcycle is in use there is a build up of static within the machine. It is necessary to ensure that this is dispersed during usage.
In order to facilitate this there is a carbon black strip built into the tyre during manufacture. This strip is moulded into the tyre before curing using carbon, as this is a good conductor of static electricity. This strip is practically invisible on a new tyre, but can appear as the tyre wears, especially if the usage of the motorcycle is not high. There is no detrimental effect on the performance of the tyre either before, during or after this strip has become apparent. The positioning of this groove is slightly ‘off centre’ and can be seen in the diagram below. (no picture was visible).

Thanks Joe!

 

[iviyth0s]

Pretty neat...learned something new today

 

[bigdog9191999]

Very cool. Wondered what those lines were on my old pr2's!

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[PhotoAl]

Thanks! Wondered what those lines were, learned something cool and new today.