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Tire wear...


rob1100r

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I have a 2000 R1100R with a low 4K on her. I purchased it with 2K. I noticed after a needed cleaning that the 'drivers side' of the front tire is much more worn than the 'passengers side' of the tire...The rear tire is evenly worn. I have kept the pressures at recommended levels for rider and BMW bags since I owned it and did not notice any odd wear when purchased. I had a '95 R1100R before this and did not experience this kind of wear on that one. I do have a buddy that has a '96 and this happened to his front tire as well, he had MEZ 4's, I have MEZ 2's.. was this just a bad batch of Metzlers? Anyone else experience this before? We don't ride on circle tracks (haha) so whats with the wear..Next question, Do the Avons outlast the others like I have read (with their deeper tread they claim longer mileage without performance sacrifice) THANKS!

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Rob, this is a topic that has been discussed numerous times here over the past 8 years. It is a common pnenomenon not just to BMW motorcycles, but to any bike with a sporting character. There are several items that seem to contribute to it.

 

The first is road crown. Roads and highways are slanted, high-left/low-right, in order to provide proper drainage. This means that in order to travel a straight line, you are always making a minor correction to the left. You may not notice it, but you are. And since you're providing slight input that causes your bike to continuously crawl upward to the left, you're creating a fair amount of "scrub" on the left side of the tire, just off center.

 

The second factor is cornering. The vast majority of people corner left much more aggressively and with greater ease than they corner right. For many there's a difference in exposing their left apendages to the ground, than their right ones, most people being right-handed and right-footed. Therefore, there's a natural tendency to be a bit more protective of the arm and leg on that side.

 

Another factor is throttle location. When cornering left the bike's throttle is out on the right, an easy reach away from the body, and perfectly capable of being modulated with the arm/elbow/wrist's natural articulation ranges. When cornering to the right, we lean right, reducing the distance between our bodies and the throttle, reducing the room available for our arm/elbow/wrist to move and control the throttle. Since throttle control is a major factor in cornering setup, stabilization and exit, when we limit our ability to move/control the throttle, we tend to be more cautious in our speeds, cornering angle, and their related loads on the tires.

 

Finally, there is the fact that we ride on the right side of the road. This means that whenever we take a left curve, there is another, tighter curve, to our inside. It is the other side of the road on which traffic heads the other way. When we take a curve to the right, there is only the edge of the road to our inside.

 

Therefore, take any two corners, one left one right, in which an identical radius can be established measured from the centerline of the road, and the actual riding radius will be greater (and thus the speed greater and the cornering forces greater) for the left curve than for the right curve.

 

Basically, a left curve is always an outside curve for us and the right curve is always an inside curve. Same central radius, but two different speeds, always slower when turning right.

 

Add to that our reluctance to expose our right appendages to potential danger, plus the relative awkwardness of operating the throttle with our bodies leaned right, and you can see why on any given any road with an equal number of identical left/right curves, we will have scrubbed much more rubber off the left side of the front tire than off the right. We actually do the same at the rear, but the rear tire has far more rubber on it than the front does, so it's hard to spot the physical differences by just looking at the rear tire's left/right sides.

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That makes more than enough sense to me! Road crown for sure, since a good amount of miles we do are back roads and you easily see the crown on many of these roads better than most! Thanks for the eductaion! Now....Avons or Metz....

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So do we have any evidence of right side tire wear from our English/Aussie/Japanese members that would support Fernando's Theory of Unequal Radii Dimensions?

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I'd say it's mostly just road crown. I take exception to the other reasons.

 

I actually corner more comfortably to the right. When I first starteed riding I had a 600cc sportbike, I did a lot of track days the first 2 years and all of the racetracks I rode were clockwise so I got a lot more practice on right turns.

 

I was too young and dumb to care about protecting my right more important right side.

 

Also, I take more right handers on the street faster because left turns usually do not have a right-of-way and I end up accelerating from a stop vs. taking the turn at speed which results in a steeper lean angle. Also the tighter and slower the turn, to farther I'm willing to lean... ie. push the bike's limits. RIght turns are usually a tigher radius.

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So do we have any evidence of right side tire wear from our English/Aussie/Japanese members that would support Fernando's Theory of Unequal Radii Dimensions?

 

I've had communication with riders in the UK, and they tell me it's not as bad for them. In conversation, I've come to the concusion that two things are different for them, two things are the same.

 

Clearly, the ride on the left side of the road, so their roads crown right-high/left-low. Therefore, their constant correction for road crown would be to scrub the front tire to the right of center. Also, for them every right curve is an outside curve, every left curve an inside curve, so speeds and tire loads would likely be greater on the right side of the tire.

 

What tends to neutralize this somewhat is that, like most of us, they are primarily right-handed and instintively more protective of that side of their bodies. Also, the throttle is in the same place, so cornering to the left is still more naturally easy from the perspective of throttle control, than cornering to the right.

 

Still, I would also like to hear from UK, Australian and New Zealand members as to how all of these factors end up affecting their tire wear. Do they get more wear to one side than the other? Or do the differences of riding on the left tend to cancel each other out?

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Still, I would also like to hear from UK, Australian and New Zealand members as to how all of these factors end up affecting their tire wear. Do they get more wear to one side than the other? Or do the differences of riding on the left tend to cancel each other out?
Uggles just commented on that in another thread.
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I don't know much. But I do know this: Not EVERY motorcycle in the US exhibits this kind of wear.

Ed Zachary. Which is why I stated:

It is a common pnenomenon not just to BMW motorcycles, but to any bike with a sporting character.

It is also more common on front tires that have a V-profile (Bridgestone BT's, Dunlop Sportmax's, Avon Azaro/Storms) than those that have a U-profile (Pilot Roads, Road Attacks, etc). But that certainly doesn't mean that it happens on every bike or even on most bikes.

 

Matt, thanks for the link to Uggles's comments. I've heard from those in left-drive countries that they either don't have the problem (i.e. I surmise that the two factors that are different from ours are canceling the two factors that are the same) or they end up with excessive wear on the right side of the front tire. The latter would lead me to conclude that it is a combination of road crown and their larger radii and higher cornering speeds to the right. Also, then, body interference with smooth throttle operation and a greater instinct to protect one's right side would be lesser factors than the other two.

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'Nando, as they say a picture is worth a thousand words.

 

I just replaced this Conti Road Attack last Saturday.

 

Profile of the de-mounted tyre, left on the left:

TYRE1.jpg

 

Left side tread detail:

_DSC4812.jpg

 

Right side tread detail:

_DSC4813.jpg

 

I do not normally use a tyre this far down - it is borderline illeagal in the UK and I normally change them with about 1.5 to 2mm of tread left so the wear is much less pronounced. Also, when the tyre was mounted and inflated the difference was much less noticeable.

 

I leave you to compare to a US tire (sic)

 

Andy

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I'd say it's mostly just road crown. I take exception to the other reasons.

 

I actually corner more comfortably to the right. When I first starteed riding I had a 600cc sportbike, I did a lot of track days the first 2 years and all of the racetracks I rode were clockwise so I got a lot more practice on right turns.

 

I was too young and dumb to care about protecting my right more important right side.

 

Also, I take more right handers on the street faster because left turns usually do not have a right-of-way and I end up accelerating from a stop vs. taking the turn at speed which results in a steeper lean angle. Also the tighter and slower the turn, to farther I'm willing to lean... ie. push the bike's limits. RIght turns are usually a tigher radius.

 

If it is mostly road crown, why don't all m/c front tires in the US show this wear pattern?

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I'd say it's mostly just road crown. I take exception to the other reasons.

 

I actually corner more comfortably to the right. When I first starteed riding I had a 600cc sportbike, I did a lot of track days the first 2 years and all of the racetracks I rode were clockwise so I got a lot more practice on right turns.

 

I was too young and dumb to care about protecting my right more important right side.

 

Also, I take more right handers on the street faster because left turns usually do not have a right-of-way and I end up accelerating from a stop vs. taking the turn at speed which results in a steeper lean angle. Also the tighter and slower the turn, to farther I'm willing to lean... ie. push the bike's limits. RIght turns are usually a tigher radius.

 

I think you'd have to agree that your sportbike/track days experience is more the exception than the norm. But because of your track experience, it's easy to see why you'd be quite comfortable cornering to the right. However, for the average person, everything from tight U-turns to high-speed sweepers is usually more comfortable going to the left. We've even had discussions about this on this website.

 

As for right turns having a tighter radius, that's true. However, that also means they have a lower speed. And if tire wear in the corners is primarily caused by the amount of inertia that needs to be redirected, and if inertia is something like mass x velocity (some of you engineer guys correct me here), then the greater velocity in left-hand turns means more inertia to redirect and will likely contribute to greater tire wear.

 

I'm not an engineer and I didn't stay at a Holiday Inn last night. I'm SUGGESTING all of this based on my relatively rudimentary understanding of these things. And, not having found a better explanation for the left-side tire-wear issue, I believe these factors to be the most dominant ones at play here. However, I'm always willing to learn something new be it factual or just opinion.

 

Who else would like to contribute to all our collective information?

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I have a Pilot road that wore this same way . Just about 6000miles . I am a little bummed . I didnt think I road on straight enough roads for this to happen . I was blaming it on not enough air I was running 38lbs .I later read I should be running 41 .Dave

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Profile of the de-mounted tyre, left on the left:

TYRE1.jpg

So your tyre (sic) wore more on its left side, despite driving on the left in the UK?

 

That argues against the idea that road-crown accounts for the wear on the left side here in the US.

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OK, here is my 2 cents worth?

 

I read all the posts, went for a ride (100 mi) and tried to be aware of all the things my instincts normally do with out my intervention !!

 

I recently replaced my front Avon Azro @ 3500 miles. Looked just like Andy's on the left side.Didn't hold up well at all.

 

Replaced my rear Battlax @ 11,000 mi, also scalloped on one side.

 

Been running 38 lbs. front 40 rear.

 

Replacements were New pilot Roads.

 

1st. thing I notices was that I was leaning to the left all the time. PTTR.

 

Set throttle and take my hands off the bars and it wants to go right.

 

Rode on some long straight 2 lane roads. Rode in the center (top of crown), rode in the left lane, when I had good long range vision, rode normally in the right lane. Bike still had PTTR, less on the top and on the left, but still there.

 

I seem to turn tighter on right turns/curves than left. I think due to torque and right curves are easier and smoother.(the way I ride)? I am right handed, so I do not think that is an issue, at least for me anyway.

 

I am still running 38f & 40 rear, solo. The new little fingers on the pilot roads are now worn off and appear to be evenly worn right, center, and left. I never get to the chicken stripe. I'm chicken/conservative rider. Been doing it a long time and still here to talk about it !!

 

Strange feeling leaning to the left all the time with the new PRs. I never experenced this before till the new PRs ?????

 

Commets please.

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There must be a number of factors involved, my front Azaro went 7,000 miles with no apparent cupping and my last BT-020 rear wore badly on the left side and was replaced at 7,000. Other than a Macadam 90 I have not had serious front cupping problems with Pilot Roads, or the Azaro. I did experience front cupping on the BT-020 but not as severe as the Michelin Macadam.

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