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#1002118 - 12/08/17 09:45 PM Re: TIRES FOR 2004 RT + ? [Re: Cedarone]  
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cat0020 Offline
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Or you could have two set of wheels/tires.. change them as you feel.. better yet... get some spare motorcycles... one for the spirited rides, one for commute and another for long distance touring.


Master your environment, and you will survive just fine.
Chances favor the prepared mind.
#1002119 - 12/08/17 09:47 PM Re: TIRES FOR 2004 RT + ? [Re: Craig G.]  
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greiffster Offline
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Originally Posted by Craig G.
Quote: "Also, in countries that drive on the R/H side of the road L/H curves are longer than the comparable R/H curve due to needing to stay right of the center line."

I've often heard this and made me wonder what front tire wear looks like in the UK... sure enough, their front tires wear on the right side.

http://www.cambriantyres.co.uk/motorcycle-tyre-wears-more-on-right-side/


FWIW, My '03 1150RT showed very little difference regarding R/H and L/H tire wear.


But, the problem I always have with sketches like in the above link is the scaling.......
[Linked Image]

Here in the US, normal crown on roads is +/- 1.5% (or 2%). It looks like this when scaled correctly.....
[Linked Image]

And when you blow up the front tire and look a the relative slope across the width of the tire, it's unimpressive. A couple of millimeters vertically across the width.
[Linked Image]

When folks talk about uneven wear left to right and post pics, the wear is usually well up the side of the tire. Simply not caused by a 1.5% crown.

Regarding the length of L/H curves (in the US) being longer than R/H. Ok, but how much.....

A minimum radius curve for a design speed of 55mph is about 1200ft. If you assume a 90deg curve, than the traveled distance (about 1885ft) between the two lanes differs by about 19 feet. Or approximately 1%. I doubt you'd be able to visualize a 1% wear difference on either side of the tire.

If you are seeing L/H tire wear noticeably more than the R/H side, and that wear is more than say 1/4" (really 1/8") vertically up the tire, you turn left harder and faster than you turn right.






-Mike
'08 GSA
"If I don't like it, I'm not blaming myself!"
K. Greiff
"Anything worth doing is worth overdoing."
M. Jagger
#1002122 - 12/08/17 10:22 PM Re: TIRES FOR 2004 RT + ? [Re: greiffster]  
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dirtrider Offline
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Evening greiffster

Regarding the length of L/H curves (in the US) being longer than R/H. Ok, but how much.....

A minimum radius curve for a design speed of 55mph is about 1200ft. If you assume a 90deg curve, than the traveled distance (about 1885ft) between the two lanes differs by about 19 feet. Or approximately 1%. I doubt you'd be able to visualize a 1% wear difference on either side of the tire.

Evening greiffster

It really depends on lane position & aggressiveness. Remember that a rider can see much farther through most L/H curves so they tend to ride them faster & leaned over more.


D.R. ___
Sent from my rotory dial wall phone!
#1002124 - 12/08/17 10:50 PM Re: TIRES FOR 2004 RT + ? [Re: dirtrider]  
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greiffster Offline
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Originally Posted by dirtrider

It really depends on lane position & aggressiveness. Remember that a rider can see much farther through most L/H curves so they tend to ride them faster & leaned over more.


Indeed. My point was that the difference in length of the L/H versus R/H curves is mostly negligible as it relates to tire wear.


-Mike
'08 GSA
"If I don't like it, I'm not blaming myself!"
K. Greiff
"Anything worth doing is worth overdoing."
M. Jagger
#1002172 - 12/10/17 03:56 PM Re: TIRES FOR 2004 RT + ? [Re: Cedarone]  
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cat0020 Offline
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Keep in mind the turning radius difference between left vs right turns in different traffic pattern.

In right side drive traffic pattern, the left turns will likely require twice the distance to complete the turn vs a simple right turn at a regular 4-way intersections.

Twice a year, I head out on my uneven worn front tire bike and ride for one of these highway mergers for 30 min session of right turns just to even out the tire wear pattern a bit:

[Linked Image]


Master your environment, and you will survive just fine.
Chances favor the prepared mind.
#1002209 - 12/11/17 03:17 PM Re: TIRES FOR 2004 RT + ? [Re: cat0020]  
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greiffster Offline
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Originally Posted by cat0020

In right side drive traffic pattern, the left turns will likely require twice the distance to complete the turn vs a simple right turn at a regular 4-way intersections.


This one is bothersome to me as well. On paper the left turn is probably twice the distance of the right, at an intersection. But when you are riding/driving the L/H turn, don't you pull well out into the intersection before initiating the turn? I'm not sure the actual distances in the turn differ that much. BUT, even if the lengths do differ, is it really enough distance to result in noticeable wear? And like your photo above, won't a little bit of interstate driving balance things out? Either clover-leaf or diamond interchanges, it's almost always right turns on/off.


-Mike
'08 GSA
"If I don't like it, I'm not blaming myself!"
K. Greiff
"Anything worth doing is worth overdoing."
M. Jagger
#1002213 - 12/11/17 04:14 PM Re: TIRES FOR 2004 RT + ? [Re: greiffster]  
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dirtrider Offline
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Originally Posted by greiffster

This one is bothersome to me as well. On paper the left turn is probably twice the distance of the right, at an intersection. But when you are riding/driving the L/H turn, don't you pull well out into the intersection before initiating the turn? I'm not sure the actual distances in the turn differ that much. BUT, even if the lengths do differ, is it really enough distance to result in noticeable wear? And like your photo above, won't a little bit of interstate driving balance things out? Either clover-leaf or diamond interchanges, it's almost always right turns on/off.


Morning greiffster

Some do, most don't-- Most just arc the L/H corner at a speed at a lean they feel comfortable with. (lot longer & a lot faster).

The R/H corner is much sharper so the speed is way lower plus it usually doesn't get a constant arc a but change in lean throughout the corner.


D.R. ___
Sent from my rotory dial wall phone!
#1002273 - 12/12/17 01:12 PM Re: TIRES FOR 2004 RT + ? [Re: Cedarone]  
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Mainly chip and seal here in the Hill Country of TX.......I find that I get the best wear out of Pirelli Angel GT's, which are quite fairly priced. Usually about 4/4.5k on the rears and 6.5/7k on the fronts with fairly aggressive riding. Always LH side of the fronts wears down first. I run 37 and 39 solo with 38 and 42 when 2up.


Phil C.
2003 R1150RT "DaRTh"
2014 Jeep Grand Cherokee Overland 4x4 Diesel "Smiffy"
2011 Kia Optima EX "Meosjin Chalo"
#1002322 - 12/13/17 08:07 PM Re: TIRES FOR 2004 RT + ? [Re: Cedarone]  
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eliastfk93 Offline
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The trait is normal, I've experienced similar wear patterns on my rockster. But as mentioned before, I would highly recommend giving the pilot road 3 or 4's a try. To this day they're the best touring/commuting tire i've ever ridden on. They should last a good long while too.

#1002331 - 12/14/17 12:25 AM Re: TIRES FOR 2004 RT + ? [Re: Cedarone]  
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EffBee Offline
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I’m not an engineer and I don’t play one on TV. But this is what I’ve culled from years of reading about the subject of uneven tire wear. And if I’m full of bull, one of our resident smarter people (of which we’re blessed with many) will tell me so. Gently, please.

All of the advice above is excellent. However, no one thing is responsible for uneven tire wear. Instead, it is a combination of the above and how it takes place as you ride and corner.

As Greiffster points out, a simple 1.5% road crown will not create the problems you’ve experienced. However, when you add the two sides together, you get 3% (we’ll get to how that math works in a minute), and 3% can be a substantial contributor. For the sake of this discussion, let’s assume the measurement of 1.5% so we have a constant to work with. And since it’s probably better to work in degrees, let’s just round it up to 2 degrees of road crown, or a summed difference of 4 degrees between the two sides.

First, there’s almost imperceptible differences in side-to-side tire wear when riding on a crowned road in a straight line. A bit more when braking, because the front tire deforms (compresses) some and thus exposes a larger portion of its side tread to the 2 degrees of road crown that exists (plus there's a microscopic amount of side slip due to the road crown), but we’re splitting hairs. Uneven front tread wear comes from cornering and, if you’re a bit of a trail braker, from that, too. But for this explanation, let’s work on the cornering.

Let’s assume a cornering angle of 30 degrees. Let’s make this our cornering constant. As has been explained, in countries where we drive on the RH side of the road, the road falls away from us to the right (for water drainage). Also, on any road, a left curve takes the outer of the two radii, the right, or opposing lane, represents the inner radius (going the other way). On a right curve, the inverse is true as the right lane is the tighter and (in terms of speed) the slower of the two. As anyone who’s watched a wheel go around knows, the parts closer to the axle (axis) spin slower than those farthest away from it. So if you look at any corner, left or right, as a part of a circle, i.e. an arc which has an axis, you can understand more easily how one side is the faster side depending on which way the corner goes.

Now let’s take that 30-degree motorcycle lean angle and carry it through a left-hand curve. The 30 degrees is measured from vertical. This assumes a road surface perpendicular to that vertical line. But it’s not perpendicular and thus not really “just” a 30-degree cornering angle because if you add in the 2 degrees of road crown, you’ve got an effective cornering angle of 32 degrees when arcing left. Not only that, but two of those 32 degrees are being used by gravity to pull you away from your intended line, because of the negative grade represented by the road crown. Thus, in order to hold your line, your tire scrubs, but so subtly that you usually don’t feel it. Still, it’s wearing by sacrificing its surface to the heat and shredding that it takes to change the direction of a loaded 700-lb sport-touring bike.

Now let’s take that same curve and make it a right hander. Suddenly the 30 degree lean angle is reduced to 28 degrees because of the 2 degrees of camber (road crown) that works to create a positive road angle into which to arc your bike. Thus the differences between a left curve at 30 degrees of lean and a similar right curve at 30 degrees of lean, total 4 degrees. That’s enough of a difference to create some different wear characteristics. More scrub and wear going left, and less going right (all else being equal).

Beyond this, we can calculate in a number of other factors if we want.
• Take away our constant of a 30-degree lean and in the real world, road speeds would be different (greater) through a left hander vs. a right hander. More speed, more scrub (tire wear).
• Plus there’s the fact that riders are generally more comfortable leaning to the left (most of us are right handed and are more protective of our natural side). Thus we’re more comfortable cornering harder to the left.
• Plus turning left leans our bodies away from the throttle and straightens out the right wrist which makes for more comfortable and controlled throttle application leading to earlier application (vs. leaning our bodies right which cramps the wrist’s ability to rotate smoothly and often delays confident throttle application), all of which contribute to making the front tire work harder and sooner when exiting a left curve, and on an already 4-degree surface differential,
• etc. etc. etc.

The above, along with many other factors (many of which are touched on above) is what I’ve been led to believe are the major contributors to uneven front tire wear. Ten, twelve, fifteen curves per mile on your favorite set of twisties, mile after mile, through hundred and eventually thousands of miles, and the inequities build up until the tire wear differences are noticeable.


Cary, Gleno, Rodger, Paul,
Godspeed, my brothers.
We will never forget you.


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