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Very Famous Person
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Discussion Starter #1
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On another website, this comment was made:

"I know for sure that when the BT45 rear on front of my Goldwing is run with arrow forward does not have the hold that it does reversed."

My response:

I would respectfully differ. You don't know that unless you do a test with the same bike in the same conditions (highway pavement composition, wetness, temperature, air pressure, etc.) at the same time with the same parameters. Otherwise you are just guessing. You can tell if one tire gets longer mileage (although it's unlikely you rode the same for the entire life of each one) mostly because that's an average of a long time/mileage test.

Check the number of edges on the tire grooves and the angle. It doesn't matter whether the angle is to the side, frontward or backward, only that it's the same amount whichever way the tire is rotated. What can happen is that after a number of miles, the tire can be worn so that the groove edges are worn so that they have a sharper lip one way and a more rounded lip the other. Usually you can feel this difference on a tire with your hand after 5,000 or so miles. If you rotate the direction of the tire after it's worn down so there is a different pattern of grip (i.e., the prominence of the lip), then that would grab more one way than the other would. That's the only thing that can modify the amount of traction. Things like tire pressure, or amount of tread, tire size, or rubber hardness would be the same either way, so none of those things would make any difference.

The grooves themselves are there only to channel water away from under the tire and they do that regardless of the angle. Have you ever noticed how auto tires are frequently designed so the tread on one side angles forward and on the other side angles back? All those tire can be used on either side of the car, front or back, front wheel drive or rear wheel drive. You think the water only gets pushed out on one side that's angled back and gets forced underneath the tread on the other side? Of course not.

The tire tread depth (actually, the "height" of the blocks or higher parts of the tire) controls most of the "squirm" that a tire has which is why an auto road racer will grind off 1/2 to 2/3 of the tread of a new tire before using it so he will have the same traction without any movement of the tire blocks. Haven't you ever wondered why Indy racers only get 40 laps, or so, on a set of tires? If the amount of tread didn't matter in grip and consistency, they could put maybe 2" of tread on the tires so they wouldn't have to stop long enough to change out the tires. On the other hand, it is one reason why street bike tires have so little open area (to minimize the amount of lip) and have such a small amount of tread depth (typically 1/3-1/2 a car tire's depth). Contrarywise, notice how off-road bikes have knobby tires with much tread depth and lots of blocks with many lips for traction. Completely different type of tire for completely different use.

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Very Famous Person
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Discussion Starter #3
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Correct. I just wanted to share some thoughts here.

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Retired twice: Navy and as a govt contractor
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I only know a couple of things about tires.

1. Mount them with the tread on the outside.

2. Directional tires are mounted with the arrow pointing forward. If you look at properly mounted tires you will see the tread going the same way on both sides of a vehicle front or rear.

Now I believe most motorcycle tires are directional and either a front or back, so that is the way I would mount them.

I have read of people who mount a rear tire on the front with the rotation backwards, I do not under stand it.
 

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Some motorcycle tires are directional because the tread pattern is optimized for pushing water out of the way. Other then that I can't see how there would be any noticeable difference in handling, braking, or any other performance.
 

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The front or back tires have a difference in construction because they have different forces acting on them. I guess theoretically if you turn one around it will then be okay for the opposite position on the bike.

Accept that if you do that with a directional tire, its ability to resist hydroplaning might not be as good as intended, especially at higher speeds.
 

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Very Famous Person
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Discussion Starter #7
The front or back tires have a difference in construction because they have different forces acting on them. I guess theoretically if you turn one around it will then be okay for the opposite position on the bike.

Accept that if you do that with a directional tire, its ability to resist hydroplaning might not be as good as intended, especially at higher speeds.
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Some time in the past, the direction the tire rotated was important due to the overlapping of the construction fabric. The theory was that the tires would tear apart if they rotated the wrong way. Tires are better made now, so this doesn't seem to matter any longer (if it ever did). Many bikers have used their tires each way and I have never read of anyone having a tire come apart due to the carcass becoming separated. (Just as it used to be oil changes had to be every 3000 miles is no longer necessary.)

As to water dispersal as I have pointed out above, for car tires the water dispersal works no matter the direction of the grooves. You can go look at car tires and see for yourself. One test I have read also shows that. I don't know why it would be any different for a bike.

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Save them all!
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"I know for sure that when the BT45 rear on front of my Goldwing is run with arrow forward does not have the hold that it does reversed."
There aren't a lot of people in the world who run a Goldwing that close to the ragged edge of traction, and do it often enough to notice that sort of thing..

Interesting.
 

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Very Famous Person
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Discussion Starter #9
There aren't a lot of people in the world who run a Goldwing that close to the ragged edge of traction, and do it often enough to notice that sort of thing..

Interesting.
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I don't know how aggressively this rider and his friends rode their bikes. When I've ridden the Dragon, it hasn't been at my bike's traction limits. But as to Goldwing riders' generally doing it, they can corner and accelerate better than almost any bike other than an expert on a sport bike. The Dragon seems to attract people who want to (at least once) live life to the edge. But you're right that you have to be pretty good to really be able to tell a tad bit of difference between two directions of the same tire.

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As to water dispersal as I have pointed out above, for car tires the water dispersal works no matter the direction of the grooves. You can go look at car tires and see for yourself. One test I have read also shows that. I don't know why it would be any different for a bike.

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Because, as I pointed out above, :wink: many motorcycle tires are one directional and the tread is optimized for water dispersal when the tire is running in it's specified direction.
 

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I have seen and heard that the arrow on the tires, tells the tale of which way they should be mounted.

The chain too.........(has an arrow)!!

-Soupy
 

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I only know a couple of things about tires.

1. Mount them with the tread on the outside.

2. Directional tires are mounted with the arrow pointing forward. If you look at properly mounted tires you will see the tread going the same way on both sides of a vehicle front or rear.

Now I believe most motorcycle tires are directional and either a front or back, so that is the way I would mount them.

I have read of people who mount a rear tire on the front with the rotation backwards, I do not under stand it.
My front tire can also be used as a rear tire. It was explained to me that the rear tire needs forward traction to accelerate while the front tire needs rearward traction because it does most of the braking, hence the reason to mount them in different directions.
 

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So long
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My front tire can also be used as a rear tire. It was explained to me that the rear tire needs forward traction to accelerate while the front tire needs rearward traction because it does most of the braking, hence the reason to mount them in different directions.
What size tires do you have? No way I could swap front and rear tires. My front is 120/70ZR17 and the rear is 190/50ZR17.
 

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Very Famous Person
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Discussion Starter #16
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On one of my bikes, I mount a rear tire backwards on the front. Works fine. When it starts wearing out, I'll reverse it. :)

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Charlie Tango Xray
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As Eye pointed out, wouldn't rain water be directed UNDER the tire by the rain grooves if they were mounted backwards? That would be.... bad.:eek:
Every tire I've purchased has had a direction arrow on it. Who am I to question the manufacturer that designed and made it? ;)
 

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Very Famous Person
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Discussion Starter #19 (Edited)
As Eye pointed out, wouldn't rain water be directed UNDER the tire by the rain grooves if they were mounted backwards? That would be.... bad.:eek:
Every tire I've purchased has had a direction arrow on it. Who am I to question the manufacturer that designed and made it? ;)
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What evidence did he produce? However, did you read my post? Tire manufacturers have long said that all kinds of bad things will happen if you put a car tire on a bike. It never has. Do you still believe them?

You can question things that may not be correct. Do you believe "you can keep your doctor..."? Do you believe the earth has not warmed until several years ago?

This is not to say you can't believe whomever you wish. If you want to only go by what some manufacturer says about something, fine. Go for it. I'm sure all the manufacturers that say anything are always correct.

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"Evidence?" :biggrin: What is this, a court case? Okay, how's this:

Me: Every single tire manufacturer that makes a directional tire says it is made that way and the grooves are designed and optimized to push water out from under the tire when it's run in the proper direction. If you mount the tire backwards it is not as efficient at pushing water out of the way and you increase the risk of hydro-planing. That's why every single manufacturer of directional tires puts little arrows and directions on the tire so you know which way is the safest way to mount that tire.

Ron: I put a car tire on my bike and ran a tire backwards and haven't crashed yet.

:coffeescreen:

Tire manufacturers have long said that all kinds of bad things will happen if you put a car tire on a bike. It never has.
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And you can go right on believing that particular lie as long as you'd like. :wink:
 
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