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Discussion Starter · #1 ·
I received a pair of Kenda K657 Challenger tires today from DennisKirk.com. The front tire has a rotaion arrow and the rear tire has a Drive arrow. With them pointed in the same direction, the tread patterns are opposite of each other.

This can't be right?
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Ace Tuner
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This can't be right?
The tire sold for the front is actually a front -or- rear tire.
The arrow is correct for rear fitment. Spin it the opposite direction when mounted on the front.
It's the cheap tire way of doing things.


EDIT:
I should have looked at the pic's more closely... See post # 9.

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Discussion Starter · #4 ·
The tire sold for the front is actually a front -or- rear tire.
The arrow is correct for rear fitment. Spin it the opposite direction when mounted on the front.
It's the cheap tire way of doing things
I'm not sure I follow that logic. Why would the front tire being used as a back tire have the opposite tread as the actual back tire?

In my recent buying experience these tires are offered as either front or rear. This front is a 100/90-18, they do not offer a 100/90-18 as a rear tire.

I don't know much about much, but it sure looks to me like there has been a factory mistake.
 

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Discussion Starter · #6 ·
I just heard back from the vendor. Front tire is defective, as are all of their recent stock, which means they won't be supplying me with a replacement any time soon.
 

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Discussion Starter · #7 ·
Whelp, it has been pointed out to me, and confirmed by a little more research that it is not uncommon to have opposing front and rear treads. News to me, but the explanation seems sound. Rear functions better with the V in the pattern pointing forward, and the front functions better with the V facing backwards. Good short video on it here.


Now to tell the customer service guy I am dealing with at Dennis Kirk.com that we are both wrong, the tires are not defective.
 

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Another way of saying it, although it doesn't really matter for all practical purposes, is that the rear tire 'pushes' the bike with the force of the coming from the rear to the front. This is as the rear tire tread is (in part) self cleaning. The front tire is being 'pushed' by the bike and so the force on the tire tread comes from the front to the rear. In this case, the mud or water will be forced out away from the tire at the tread. This is the theory, anyway.

Many riders have used rear tires with more tread on them (often called 'double darksiders') on the front of their bikes in order to get more tread mileage. In this case, they usually don't notice any difference in how the bike handles whichever direction the mount the tire. On the front of my RoadStar, the rotor on each side is the same, so after 15,000 miles I turn the whole wheel around so the tread is going the opposite way and any nubs on the tread blocks are evened out. I run it 15,000 miles that way before it needs to be replaced.

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I'm not sure I follow that logic. Why would the front tire being used as a back tire have the opposite tread as the actual back tire?.....
..... Why would the front tire being used as a back tire have the opposite tread as the actual back tire?
Maybe I was thinking of cheap Cheng Shin tires that do the front/rear fitment thing because...
Taking a second look at the tire sold as a front I now see that the rotation arrow and tread are correct for front fitment. The reasons are as RonK stated. Also the rear tire has to deal with acceleration forces much more than braking force and the front only deals with the force of braking. When the tire is manufactured the tread splice is applied keeping in mind which direction of force the tire will encounter. The tread on the rear is designed in such a way that under acceleration water will be pushed away from the center of the tire. Tread on on the front is arranged so that water will be pushed away under braking.

S F
 

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I've often wondered if tread direction even matters unless you are going 150mph or more. Would the average rider ever see a difference in handling? And if so, what speed or condition would the average rider experience the difference. The average rider rarely goes over 95mph(my estimate). Add to it that most won't even ride in rain, let alone extremely heavy rain. I really doubt they would ever see where tread direction plays a role unless they encountered the very very rare, tread separation. Wrong ?????
 
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I've often wondered if tread direction even matters unless you are going 150mph or more. Would the average rider ever see a difference in handling? And if so, what speed or condition would the average rider experience the difference. The average rider rarely goes over 95mph(my estimate). Add to it that most won't even ride in rain, let alone extremely heavy rain. I really doubt they would ever see where tread direction plays a role unless they encountered the very very rare, tread separation. Wrong ?????
It matters. Years ago I mounted a front tire backwards because I was unaware of this, and the tire immediately, and rapidly, started to wear funny with a feathering pattern on the tread blocks, like similar to when you run a motorcycle tire really low on air or like after a flat. Turned it around and it started wearing normal.

The tread blocks do move around quite a bit since motorcycle tires utilize extremely soft rubber. So if you apply pressure in the wrong direction in a way the tread design was not intended, you get the deformation of the blocks.
 

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I just heard back from the vendor. Front tire is defective, as are all of their recent stock, which means they won't be supplying me with a replacement any time soon.
I would have found that very hard to believe. Which you've discovered.

Whelp, it has been pointed out to me, and confirmed by a little more research that it is not uncommon to have opposing front and rear treads. News to me, but the explanation seems sound. Rear functions better with the V in the pattern pointing forward, and the front functions better with the V facing backwards. Good short video on it here.


Now to tell the customer service guy I am dealing with at Dennis Kirk.com that we are both wrong, the tires are not defective.
The concept is sound. I can certainly see how it made you do a double take though. And I don't trust many CS reps anyway. They're often not even familiar with product.
 

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It matters. Years ago I mounted a front tire backwards because I was unaware of this, and the tire immediately, and rapidly, started to wear funny with a feathering pattern on the tread blocks, like similar to when you run a motorcycle tire really low on air or like after a flat. Turned it around and it started wearing normal.

The tread blocks do move around quite a bit since motorcycle tires utilize extremely soft rubber. So if you apply pressure in the wrong direction in a way the tread design was not intended, you get the deformation of the blocks.
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How a particular tire reacted to its mounting position is dependent on so many things. Read this post I made some time ago:


Tire hardness is all over the place on both auto and m.c. tires. Not always mentioned is that some tires are a dual compound and the center is much harder (like 80 on the durometer) and the tread sides like 65. This makes judging how "hard" a tire is complicated. :unsure:

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How a particular tire reacted to its mounting position is dependent on so many things. Read this post I made some time ago:


Tire hardness is all over the place on both auto and m.c. tires. Not always mentioned is that some tires are a dual compound and the center is much harder (like 80 on the durometer) and the tread sides like 65. This makes judging how "hard" a tire is complicated. :unsure:

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This was a Bridgestone Battlax S22. So it's super soft, basically it's a racing tire compound.
 

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On some of the tires for older bikes I've seen one arrow pointing in CW direction if used on the front and CCW if used on the rear...on the same tire. I think it was on a Coker tire for a vintage bike? Thought I was seeing things but it has to do with the way torque is applied to a rear tire vs a front.
 
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