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Flat ridge in the center of front tire?

I have a pair of Michelin Pilot Road 2 on my R1100RT. While doing routine maintenance I just noticed, and was much surprised, that there is a pronounced flat ridge that runs down the center of the front tire, all the way around. It is about 1 1/4 inch wide. I mean it is flat. There are definite edges to it all the way around, on both sides, where it drops off to the sidewalls. I can see it on the rear tire also, but not as pronounced because of the larger radius. These are "dual compound" tires. The previous owner put them on. He seemed to like the brand and the tire. Highly recommended them. But I don't know how many miles they have on them.

I can't remember ever seeing tires that didn't have a continuous curve all the way across, even when worn down. It doesn't seem like this would be the best design for a tire. Is this the way they should look, with the flat ribbon around them? Are they worn out when they get this way? I"m wondering if this isn't a large part of the reason the bikes seems less than rock solid at 70mph on the expressway. I will try to post a picture.
 

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How much tire pressure do you run in that tire?

I run 40# in the front, and 42# in the rear with Dunlop Roadsmarts. The shop said to run high #.
 
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For one person, I have it noted to run at: front-32, rear-36 Psi. It's usually just me, so that is where I try to keep the pressure. If I plan on two up riding, I would go to F= 36, and R= 42. I don't know exactly where I found those numbers. Maybe under the seat. But, it could have been on here, also. Too high, too low?
 
Here's a pic of mine when I took it off my R1150RT. It was on the bike when I got it and I put an additional 11,000 on it.
Why do you feel the bike is less than rock solid?
New tires (RP3s) felt like a new bike.
I never felt instability on the slab but cornering is much sweeter now.


Some people take pictures of nature, I take pictures of worn out and broken stuff.
 

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I don't believe there is anything unusual here -- I road 2000+ slab miles to/from the MOA rally, and flat-centered my rear tire. Not surprised.
 
I would bump the pressure on the front to 36 psi. You also need to ride more twisties. I run 40 psi on the rear and 36 psi on the front of my RT.
 
Here's a pic of mine when I took it off my R1150RT. I

Well, that is what mine looks like. They could be twins. It sounds like this is normal for the tires, that they all get that flat spot on them. I just realized that with all the weird tread patterns they put on these motorcycle tires, it's difficult to tell when they really are worn out. On a car tire, you can tell it's down since the pattern is pretty much the same across the width, and they are also flat. On bikes, are they done when the center has no groove depth, or when the sides are getting shallow grooves? Or is it when they get a flat ring around them? After all, that is the little patch we are riding on mostly, rain or shine.

I wonder if BMW owners obsess more over small details that other bike brand owners? Harley people seem to be addicted to chrome polishing. Heck with the tires. On my Beemer, I worry that I may be using the wrong spark plug. But I digress...

I trust my life to those two tires. They have to be right.
 
I have Metzeler Tourance EXPs on my GSA. I have the same wear pattern on both the front and rear with it more pronounced on the front. I run what the Rider's Manual specifies for for two up riding all the time - 36F and 42R. The 'flat' is more pronounced on the front. Interestingly, I just looked at the Metzeler website and discovered Metzeler recommends slightly higher pressure in the front.

On My RTP, I just changed out my PR2s after almost 10K miles, again always running 36F and 42R. I had no flat wear patter on them. (although I did have some cupping until I got rid of the old, worn out OEM shocks (~ 64K on them) and installed Ohlins)
 
For one person, I have it noted to run at: front-32, rear-36 Psi. It's usually just me, so that is where I try to keep the pressure. If I plan on two up riding, I would go to F= 36, and R= 42. I don't know exactly where I found those numbers. Maybe under the seat. But, it could have been on here, also. Too high, too low?

I run 38 psi in the front for PR2's. No cupping or flat spots. But, there is an edge between the dual compound when they are worn out. No slippage or problems stopping in the rain. But, they only last about 9-10k miles. Maybe the PR3 will last longer. The PR2's are not my favorite tire.
 
I've used up two sets on r1150r getting 9-10k each. At 2k or so I had a ridge between the hard and soft compounds as the soft compound portion wears faster. Toward the end of tire life, there was some flattening in the center hard portion. I expect that more freeway travel would lead to more flattening. My pr2's had lots of tread in the center hard portion when the softer tread on the sides was worn out. The original posted pictures a lot of straight line miles. Like others, I did not notice any effect on feel or handling from the different rates of wear between the hard and soft compounds. While the wear patter of the ps2's made me nervous at first I have come to trust them. I'll be installing a set of ps3's this winter.

John Peck
Maple City, Mi
R1150R
F650GS
 
Find more twisties. This what happens when you go straight 90% of the time. I run Dunlap road smart 2 on a R1100RS and sad to say mine in up looking like that too.
 
If I am following the posts, it sounds like this is: 1) A very common, if not inevitable tire wear pattern that occurs, 2) Not a hazardous condition from a safety viewpoint, and 3) Should not affect the way the bike handles at higher speeds.

I am going to go to higher pressures on both front and back on mine. See how that works.
 
As the flat spot gets wider, you may feel it a little harder to lean into a turn. Kinda like running a car tire on the front and back.

Then when you put new tires on (both front and back) your handling will be sharp and quick again.
 
I wonder if that is why the PR 3's came out; to rectify the premature wearing of the center tire.

MICHELIN Pilot Road 3
The segment’s new benchmark surpasses its predecessor, the MICHELIN Pilot Road 2

An unrivalled grip in the wet1 thanks to the revolutionary new MICHELIN Sipe Technology (XST)3
An unbeatable tire life2 thanks to MICHELIN’s latest-generation 2CT dual-compound technology
All of this plus even wear and life-long performance thanks to full-depth MICHELIN XST3 sipes
 
I don't think that the PR2 has a particular problem with premature wear in the center section. My personal experience (2 sets and about 18K miles) is that the harder center section wears far longer than the softer side sections. Any motorcycle tire will wear flat if you ride mostly in a straight line. From the Michelin website, it appears that the PR3 front actually has a narrower hard (center) section than the PR2. The compound distribution on the rear tire appears to be the change. The main difference between the PR2 and the PR3 appears to be in the tread pattern.
 
Tires

Same issue on mine when I went on a 4k mile road trip straight down the highways. Got about 10k on PR3's and could have went more but it was a convenient time to get them changed and had another big trip planned. Ride that bike on some twisty roads and round those corners off.
 
I wonder if that is why the PR 3's came out; to rectify the premature wearing of the center tire.

MICHELIN Pilot Road 3
The segment’s new benchmark surpasses its predecessor, the MICHELIN Pilot Road 2

An unrivalled grip in the wet1 thanks to the revolutionary new MICHELIN Sipe Technology (XST)3
An unbeatable tire life2 thanks to MICHELIN’s latest-generation 2CT dual-compound technology
All of this plus even wear and life-long performance thanks to full-depth MICHELIN XST3 sipes

PR3's were introduced because there always has to be something newer and better. Just wait til you see the new PR4.
 
Your tire looks to have normal wear for running straight roads at those pressures. There are Tread Wear Indicators in some of the grooves that indicate when the tire is worn out. I like to change mine when the groove is twice as deep as the height of the indicator bar.
 
The PR2s on my R1100RS have the same wear pattern. I run about 36/40 psi F/R. A lot of my riding is on straight roads (I do live on the Texas Gulf Coast). My next tires will probably be PR3s and see how they wear.
 
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