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Discussion Starter #1
i'm on my fourth set of tires on my '04kgt, and am puzzled about something. i've had z4, diablo, z6 and now pilot II on my rear and to look at the tires, they don't seem to have any tread in the center of the tire. the design is purty, and flows from the side of the tire toward the middle, but only the end even crosses the middle of the tire. when the tire is on the road, only the tread fingers cross the center of the tire, and it looks effectively like like i'm riding on bare rubber. more tread, obviously, on the sides, but i'm talking about straight up riding. anybody got an explanation?
 

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An explanation of what? The more rubber you have on the road in your contact patch, the more traction you have. Slicks have more traction than tread does. The grooves are only there to channel water away from the contact patch, reducing the tendency to hydroplane which is far less of a problem on motorcycles than it is on cars, with their flat tire face.

Personally, I've never hydroplaned a bike, no matter how worn the tires were, and I routinely ride through thunderstorms, tropical storms and the fringes of hurricanes. The crosswinds are more of a problem than water on the road is. Then again, in 40 years of riding I've never taken a bike over 90 mph and usually I'm just poking along at slightly less than the speed limit.

regards,
Joe
 

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I don't think it matters how fast you're going. Within reason of course. I've ridden through puddles 2 or 3 cm deep at 150 kph without hydroplaning.
 

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My only complaint with the solid center tires mentioned by the OP is that you have no reference as to tread wear. At 5-6K you think you have a lot of use left on the tire, then in another 200mi. the cord is showing.
I can't see any reason the tire manufacturers don't put measuring holes in the tread like there are on slicks.
 

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For solid center tires they should cast in coloured markers in the same compound that change as the tire wears.
 

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billbeemer said:
i'm on my fourth set of tires on my '04kgt, and am puzzled about something. i've had z4, diablo, z6 and now pilot II on my rear and to look at the tires, they don't seem to have any tread in the center of the tire. the design is purty, and flows from the side of the tire toward the middle, but only the end even crosses the middle of the tire. when the tire is on the road, only the tread fingers cross the center of the tire, and it looks effectively like like i'm riding on bare rubber. more tread, obviously, on the sides, but i'm talking about straight up riding. anybody got an explanation?
More traction with solid center and less of a chance of cupping..The front tire clears the water for the rear....
 

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The last set of tire i took off my bike were pilot powers ( not the II's ) and the front had BAD cupping on the one side. The dealer told me it was from cornering more to the right than the left..... BS, anyways what causes the cup-ing ?
 

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Cupping is usually caused by the flex of the blocks or sections flexing...a block being the section of rubber bordered by the tread grooves...as the tire rotates and comes in contact with the road surface the block or section flexes as an independent part of the tire and not as a whole.....causing individual wear sections.... on a slick this is not the case and your tire is more sturdy when cornering ...not so much that there is more surface area but more to do with stabilization in the tire surface its self.... If you think about it with a slick you have less weight per square inch contacting the surface than you would with a tire of the same size with tread...the slick would carry the same load on a larger suface area and more stable but would "float" more (because of less PPSI contact) than a treaded tire would.
 

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BAK04GT said:
More traction with solid center and less of a chance of cupping..The front tire clears the water for the rear....
Which is why tire manufacturers insist you don't mix brands. The front is designed to work with the rear especially in the rain
 

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Jeromy said:
The last set of tire i took off my bike were pilot powers ( not the II's ) and the front had BAD cupping on the one side. The dealer told me it was from cornering more to the right than the left..... BS, anyways what causes the cup-ing ?
Could be a few things;
worn shocks
not in ballance
hard on the brakes, flat spotting
Some times the tire batch screws up and too much carbon is in spots of the tire.
 

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Discussion Starter #11
thanks guys.........

thanks so much for clearing that up! i really learned something about tires. somehow, i always associated treads with grip, now know it's the other way around. i'll never look at another superbike rear tire the same way again. thanks again, guys.
 

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Ditto bazra, many factors affect cupping. Every bike has an inherent 'weave' speed due to its geometry. We ride through a complex formula of suspension settings, geometry, surface conditions, loads, riding styles, etc. Some tread patterns and compounds perform better in one set of conditions than another. Occasionally, as I once did, you will get a tire manufactured out of round or whathaveyou. While we may have different expectations, after a few sets of tires, you can begin to see a 'pattern' (pun intended) in how certain tread styles work on your bike with your set up. Front tires with a center groove (D220, BT020, etc) cup more rapidly and become annoying much more rapidly on my K12 than those without a center groove (D205, Mich Power, BT010, etc). These tires generally have a softer compound, but since they don't cup as much on my bike, their mileage can sometimes approach the mileage where I would pull a cupping tire.
 
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Jeromy said:
The last set of tire i took off my bike were pilot powers ( not the II's ) and the front had BAD cupping on the one side. The dealer told me it was from cornering more to the right than the left..... BS, anyways what causes the cup-ing ?
Just replaced a Pilot Power 2 front with 3000mi and bad cupping on both sides. The Scottish service manager (worked on Euro racing pit crews) at local Jap dealership who's a suspension specialist said cupping is very common on sport bikes, caused primarily by hard braking while leaned over at high speeds. I just mounted another PP2; this one needed half the balance weights as previous front, so we'll see.
 

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I just ant to make sure I understand everyone's reference to cuping. My tire was worn like this :
with " low " spots evenly spaced around the left side of the tire. They were about the circumference of a tennis ball but elongated ( oval ). I guess you could also describe it possibly as dished? Like the surface of a plate????? Does this make sense????
 

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Is the tire in the picture still on the rim filled with air or are we looking at a tire off the rim?

I see the tire is worn more on one side than the other.
Is the front tire the same manufacture Mich as the rear? PR or PR 2?

This bike has a rear wheel spacer between the rear wheel and the hub, is the spacer still there in place?
 

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bazra said:
Is the tire in the picture still on the rim filled with air or are we looking at a tire off the rim?

I see the tire is worn more on one side than the other.
Is the front tire the same manufacture Mich as the rear? PR or PR 2?

This bike has a rear wheel spacer between the rear wheel and the hub, is the spacer still there in place?
First I lost the pics of MY tire before it got changed... oops. I found this on the internet and it looks just like mine did. Same wear pattern heavy on the LT side.

My tire looked like this full of air an the bike, rolling or not.
Not same manufacturer, front was PR rear can't recall.
As far as the spacer I do not know, I don't change my own tires. Too chicken honestly.
I guess its a combination of a few things possibly? I don't see how an unmatched rear tire could cause odd wear patterns on the front tho... But the wheel spacer would do it for the heavy LT side wear, but what about the dishing i described? I am watching my new tires very closely and haven't noticed any uneven wear in the first 4500 km's. I was afraid it was going to be a bad alignment job from the factory. I have heard of guys putting weights on their bars to even things out for some kind of test cause their bikes were leaning. I told this to my service guy at the local BMW dealer. He was a major $%^&* but he is gone now and there are new owners too... Might get some honest help this time when I need it.
 

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Jeromy said:
I have heard of guys putting weights on their bars to even things out for some kind of test cause their bikes were leaning. I told this to my service guy at the local BMW dealer. He was a major $%^&* but he is gone now and there are new owners too... Might get some honest help this time when I need it.
Good to know....... :clap: :clap: :clap:
Tires.....too many right hand turns on the Monashee....??????:dunno:
 

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Jeromy said:
First I lost the pics of MY tire before it got changed... oops. I found this on the internet and it looks just like mine did. Same wear pattern heavy on the LT side.

My tire looked like this full of air an the bike, rolling or not.
Not same manufacturer, front was PR rear can't recall.
As far as the spacer I do not know, I don't change my own tires. Too chicken honestly.
I guess its a combination of a few things possibly? I don't see how an unmatched rear tire could cause odd wear patterns on the front tho... But the wheel spacer would do it for the heavy LT side wear, but what about the dishing i described? I am watching my new tires very closely and haven't noticed any uneven wear in the first 4500 km's. I was afraid it was going to be a bad alignment job from the factory. I have heard of guys putting weights on their bars to even things out for some kind of test cause their bikes were leaning. I told this to my service guy at the local BMW dealer. He was a major $%^&* but he is gone now and there are new owners too... Might get some honest help this time when I need it.
billbeamer,in the very first post you talk about the REAR tire having wear problems.
Now you talk about the FRONT tire with ODD wear patterns

What tire is giving you the ODD bad wear?
what tires do have on the bike today? are they new and the same make?
How many miles are on the bike?
what air pressure do you run?
what is the size of the rear tire? and what is the size of the rear rim 5" or 5.5"?

If you have two new tires on the bike now, try this;
what is the air pressure now?
does the bike drift to the right when you ride on a flat road like a 4 lane road ? "not a two lane road, it has too much crown on it"

Now if your tire pressure was not at these setting 40 PSI front and 42 PSI rear then air them to that PSI and see if the bike still drifts. and how hard does it drift?

most but not all K1200RS/GTs will drift a little to the right.
most of the time with 2 NEW name brand tires the drift will not be very great.
But in some cases if the rear wheel spacer is not used the bike will drift hard to the right.
 

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bazra said:
billbeamer,in the very first post you talk about the REAR tire having wear problems.
Now you talk about the FRONT tire with ODD wear patterns

What tire is giving you the ODD bad wear?
what tires do have on the bike today? are they new and the same make?
How many miles are on the bike?
what air pressure do you run?
what is the size of the rear tire? and what is the size of the rear rim 5" or 5.5"?

If you have two new tires on the bike now, try this;
what is the air pressure now?
does the bike drift to the right when you ride on a flat road like a 4 lane road ? "not a two lane road, it has too much crown on it"

Now if your tire pressure was not at these setting 40 PSI front and 42 PSI rear then air them to that PSI and see if the bike still drifts. and how hard does it drift?

most but not all K1200RS/GTs will drift a little to the right.
most of the time with 2 NEW name brand tires the drift will not be very great.
But in some cases if the rear wheel spacer is not used the bike will drift hard to the right.
I think the only thing i said about my rear was that it was a different make and wrong size... It was a 175/55 i believe.... way wrong. And handled reeaaalllly bad. I put 2000kms on that one then put on the new set that is on there now.
I HAVE 2 NEW TIRES with 4500 km's on them: Mich PR 2's
The tire that was wearing poorly was the front.
14'500 Km's on the bike.
I run the 40/42 PSI
I have the sport rims so i believe they are the 5.5
I have not noticed any drift. Tried to imagine it even but it just wasn't there.
As far as the spacer goes, I do not know if there is one. I took my bike into the dealer for a service and had the tires done at the same time. I could pull the tire and look if i had to i suppose.
 

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Some very interesting reading here on the "Pull to the Right" , tires wearing lopsided and the lenght someone has gone to correct the problem on a R1100RS.
Different bike, but the physics are the same. :bmw:


http://robertsilas.com/documents/35.html
 
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