Is this cord starting to show through?

[Goodman4]

I was very disappointed this evening to see my rear Pilot Road 2 with only 3200 miles with this thin line down the middle:

Another spot after rotation:

I have a trip to ride the twisties of E TN and NC in a couple weeks. Except for this line, the tread wear is ok on the front and rear. I'm pretty sure I won't risk it and will rush a tire change in before the trip. Right call? Or do you think I've got a chance of a thousand miles of safe riding on this?

 

[Queensland Ken]

I always use PR2's, it's a production mark.

Just go off the wear bars.

The Angel ST's on my Trophy had a real bad mark down the center tread, but apparently it was a result of some factory process or anti static ?????

 

[El Toro Joe]

Looks fine...go ride

 

[Intech]

What they said...^^^^

 

[ionbeam]

Michelin tires have a lot of silica in the rubber to improve mileage but this also causes a serious build-up of static electricity. Michelin and other tire manufacturers add a 'static strip', sometimes known as a 'radio line' down the center of the tire to bleed off the static charge. I know of one local rider that felt his tire was splitting along that line and had his tire replaced. The line is intentional and not an issue.

Back when car tire manufactures started making extended mileage tires with lots of silica in the rubber the tires would let the entire car take on a significantly static charge. When people pulled up to a toll taker and reached out there would be an almighty large ZAP between the driver and toll taker, there were reports of it sometimes knocking the toll taker off their feet. At that point the tire manufacturers started adding the radio line into the tires. Due to the tread differences in car tires the strip isn't nearly as noticeable as on motorcycle tires.

 

[LKLD]

Never knew that, interesting. Thanks.

 

[BkerChuck]

Had that line on every PR2 I've used to date. Never knew why until now though. Just ride it.

 

[SLK50]

I've run PR2s till they looked like racing slicks and never

had cords show through.

Best tire for extended mileage.

 

[Redfish Hunter]

As usual, Ionbeam beat me to the punch. That was a question posed in one of the major motorcycle magazines a few years ago and I am glad it was. I have been able to sound smug, superior, and damned smart several times in front of folks who were worried about that line.

On my first set of PR2s that showed up on the front tire. I cannot count how many times I searched under the front fender for something rubbing that tire. It was driving me crazy. When it showed up on the back tire...

When Pop dropped his bike off to get new tires 2 weeks ago he pointed to that line on the rear PR3. He thought Something Bad was happening to it and was glad to be rid of it.

I cannot help but wonder how the static electricity flows from the tire into the asphalt or what would happen if all that static were not discharged. It is not like asphalt is a great conductor of electricity, you do not see many wires made of asphalt.

 

[ionbeam]

A static charge that you can faintly feel starts around 500 volts or so. Static charges that causes more pain are thousands of volts, it is possible for your body to have static charge voltages of up to 50kV. It doesn't kill ya because the current is so low but it can be very painful as the thousands of volts exit your finger tip.

As mentioned in a coil thread, high voltage aggressively seeks a path to ground, any old ground including the pavement. The static line may not bleed off all the charge but it does provide some limit to what builds up. Think about that sparkie charge built up on the chassis and body of your bike or car the next time your approach the gas filler with the gas hose

FWIW, auto manufactures and gas pump manufacturers have worked out a grounding scheme which prevents the fuel vapors from getting a static spark. This is why you are never supposed to fill a gas can in the bed of a pickup truck, there is no way to ground the can and fires aren't unheard of. As odd as it may sound, the act of gas flowing can cause a static charge to build up if it isn't properly grounded.

 

[Redfish Hunter]

I am familiar with the fact that flammable liquids can create enough static to ignite their own vapors. We have to establish and check grounding and continuity constantly on temporary hoses and vehicles inside my plant. Ethylene refineries are not good places to take chances.

It obviously works to dissipate the static charge to the pavement, and yes "aggressively seeks a path to ground" is a good term but few of us ever consider asphalt a "good ground". Since it works and I have not had my bike catch fire recently I have no real complaints about their engineering.

EXCEPT!!! It would be nice if they could have centered the static line in the tire carcass and kept it straight. This is not an issue with the uglier 2014 models but on the really good looking bikes like my 2015 that off-center stripe disrupts the symmetry of the photographs.

This sure blows that old theory about the rubber tires of a car protecting people in a lightning storm out of the water though. I always did laugh at that one.

 

[wheatonFJR]

I counted on that theory in 1979 when I took my brand new XS Eleven around Lake Michigan. As I was crossing the Mackinac Bridge I saw a front to the west, black as night. It rained, poured, lightning strikes left and right lighting my way in the black gloom, knowing full well that rubber tires will save me.

 

[mcatrophy]

I hope nobody believes everything they read on the Internet ...

:crazy:

 

[ionbeam]

I counted on that theory in 1979 when I took my brand new XS Eleven around Lake Michigan. As I was crossing the Mackinac Bridge I saw a front to the west, black as night. It rained, poured, lightning strikes left and right lighting my way in the black gloom, knowing full well that rubber tires will save me.

You wuz just lucky. Doesn't work that way on a bike. A car makes a faraday cage which is what protects you. As this thread starts to slip slide away, someone will start clamoring for this to be split off....

 

[BigOgre]

Add me to the list of people who learned something today. I've noticed that stripe on my tires and ran the fingernail over it more than once.

 

[wheatonFJR]

I hope nobody believes everything they read on the Internet ...

It's not April Fools Day anymore, so everything on the internet is true now.

 

[Goodman4]

Great news! I'm very glad to learn it's good for the trip. I've been running Pirelli for the last few years and Metzler before that. This is my first Michelin tire.

 

[0Face]

Great news! I'm very glad to learn it's good for the trip. I've been running Pirelli for the last few years and Metzler before that. This is my first Michelin tire.

Tire looks fine to me. One caveat though, tires wear at different rates depending on how hot it is and how you ride. With that said, the guys above are tire abusers and if they think it's it's good to go, it probably is.

 

[puppychow]

Since this is now NEPRT. I say sand it down, it will go away - till the next ride..