[Voyager]

Maybe I, over-thought this, but . . . the ground imprints would be the same, left-to-right or right-to-left, as long as the bike is ine the center!

Not "directed" toward anyone. Just . . . any agreement on . . .

Bike pointed toward left of screen.

Ground imprint of FRONT tire: >>>>>>>>>>>> (BIKE HERE) Ground imprint of REAR tire: <<<<<<<<<<<<<<<<<

(As noted, as long as the bike is between the two sets of Vees, the orientation of the Vees will be the SAME regardless of the direction the bike is pointed.)

Any agreement on typical manufacturer Vee orientation as expressed?

Again, maybe the tire manufacturers don't know what they're talking about, or, they're just MESSING with us by embossing direction-of-rotation arrows on tire sidewalls, KNOWING the guidance is in error.

There is no universal tread pattern orientation. It depends on the intended use of the tire as much as anything. Look at these different models from the same manufacturer. A couple models have the V facing down on the front, which is the orientation for wet weather traction as it displaces water the most efficiently. A couple other models have the V facing up which is better for dry pavement traction. Typically, tires designed for large touring bikes and cruisers have the V oriented down as on the Battlax and tires designed for sport bikes have the V oriented up as on the Exedra, but you can find exceptions very quickly if you look at a few different front tire brands and models and look at off-road as well as on-road tires.

I trust that the manufacturer knows more about their tire and its composition and performance characteristics than I do so I rotate the tire the way they recommend, assuming it is a directional tire. That will give you the best overall performance from that tire.

https://www.americanmototire.com/st...DGESTONE"],["Tire size","100/90-19"],["Categories","1968"]]&disable_semantics=1

 

[Voyager]

If you look at directional car tires, the V pattern is nearly universal with the point facing down in front so that it contacts the road first and pushes the water to the sides as the rest of the V rotates down and widens. This is because flat car tires hydroplane much easier than rounded motorcycle tires and thus dealing with water is a higher priority.

Also, the front and rear treads tend to face the same direction since in a turn the rear tires don’t follow as closely in the path of the front as with a single-track vehicle where it takes a very slow and tight turn to get the rear tire significantly out of track with the front. So hydroplaning of the rear tires is a bigger concern on a car than on a motorcycle.


https://tires.tirerack.com/search?w=directional tires

 

[Damocles]

If you look at directional car tires, the V pattern is nearly universal with the point facing down in front so that it contacts the road first and pushes the water to the sides as the rest of the V rotates down and widens. This is because flat car tires hydroplane much easier than rounded motorcycle tires and thus dealing with water is a higher priority.

Also, the front and rear treads tend to face the same direction since in a turn the rear tires don’t follow as closely in the path of the front as with a single-track vehicle where it takes a very slow and tight turn to get the rear tire significantly out of track with the front. So hydroplaning of the rear tires is a bigger concern on a car than on a motorcycle.


https://tires.tirerack.com/search?w=directional tires

Excellent distinction between AUTOMOBILE tires and MOTORCYCLE tires, and their respective strategic tread designs.

 

[pdwestman]

Bike pointed toward left of screen.

Ground imprint of FRONT tire: >>>>>>>>>>>> (BIKE HERE) Ground imprint of REAR tire: <<<<<<<<<<<<<<<<<

(As noted, as long as the bike is between the two sets of Vees, the orientation of the Vees will be the SAME regardless of the direction the bike is pointed.)

You are traveling left again correct?
And again I will suggest that both your front tire and your rear tire are installed in the scoop shovel directions. Should work great in the sand, could work better most everywhere else.

The front tire will get very squirrely at speed on gravel because the marbles will roll into the center, instead of being ushered out to the sides.

The rear tire will plug severely in stickey mud and be nearly useless.

 

[Damocles]

You are traveling left again correct?

I've tried (and FAILED) to convey the concept; doesn't matter WHICH way the bike is traveling, if in the MIDDLE of the diagram.

And again I will suggest that both your front tire and your rear tire are installed in the scoop shovel directions. Should work great in the sand, could work better most everywhere else.

The front tire will get very squirrely at speed on gravel because the marbles will roll into the center, instead of being ushered out to the sides.

The rear tire will plug severely in stickey mud and be nearly useless.

Another concept falling victim to, "What we've got here is failure to communicate," (q.v., Cool Hand Luke): Vee-treaded tires, when mounted according to manufacturers' direction-of-rotation arrows, TYPICALLY (exceptions may exist) orient the Vees as shown:

Traveling right to left: (Front print) >>>>>>>>>>>>>>>>> - BIKE - <<<<<<<<<<<<<<<<<<<< (Rear print)

Traveling left to right: ( Rear print) >>>>>>>>>>>>>>>>> - BIKE - <<<<<<<<<<<<<<<<<<<< (Front print)

(HEY, the Vee-orientation patterns are the SAME!!!!!!!!!)

Conclusions above based upon my experience and observation, including the Heidenau K60 Scouts mounted on two of my bikes . . . YMMV!

A picture may illustrate the concept more clearly than text . . . if pressed, I could photograph tire sidewall direction-of-rotation arrows and consequent Vee patterns . . .

If, sincerely, my text remains incomprehensible, I'll do it!

 

[Voyager]

I've tried (and FAILED) to convey the concept; doesn't matter WHICH way the bike is traveling, if in the MIDDLE of the diagram.Another concept falling victim to, "What we've got here is failure to communicate," (q.v., Cool Hand Luke): Vee-treaded tires, when mounted according to manufacturers' direction-of-rotation arrows, TYPICALLY (exceptions may exist) orient the Vees as shown:

Traveling right to left: (Front print) >>>>>>>>>>>>>>>>> - BIKE - <<<<<<<<<<<<<<<<<<<< (Rear print)

Traveling left to right: ( Rear print) >>>>>>>>>>>>>>>>> - BIKE - <<<<<<<<<<<<<<<<<<<< (Front print)

(HEY, the Vee-orientation patterns are the SAME!!!!!!!!!)

Conclusions above based upon my experience and observation, including the Heidenau K60 Scouts mounted on two of my bikes . . . YMMV!

A picture may illustrate the concept more clearly than text . . . if pressed, I could photograph tire sidewall direction-of-rotation arrows and consequent Vee patterns . . .

If, sincerely, my text remains incomprehensible, I'll do it!

They are not the same. They are the same relative to each other as both point to the center of the bike. However, they are not same relative to the earth as the frame of reference. The front V points to the right in the top example and to the left in the bottom example. :grin2: So, sameness depends on the frame of reference.

I am curious as to why this topic is of such importance to you. Have you had a handling or traction issue with your tires mounted per the manufacturers direction arrows?

I see the orientation mattering only in a few special cases such as heavy rains for street tires or really soft sand or mud for off-road tires. For dry pavement the orientation is irrelevant and same for hard packed dirt and gravel.

For wet pavement, I want my front street tires to have the V’s oriented like car tires with the point of the V contacting the road so that the V spreads outward as the tire rolls forward and pushes the water in the direction it naturally wants to follow which is forward and outward as the tire rolls forward. For soft dirt or mud or snow, I want my rear V also contacting the road first so that as it spins backwards under acceleration, it will move the dirt and mud to the side digging downward to find firmer ground. That is the way the V-bar tractor tires are oriented and for the same reason.

However, in probably 90% of the road conditions, the orientation of the tread pattern is irrelevant. On dry pavement, the best tire would be a slick with no tread pattern at all. On hard, dry dirt or hard packed gravel, a symmetric tread is just fine and a directional tread pattern adds no measurable advantage.

 

[Damocles]

Interesting discussion, accessible from this link:

Why do motorcycle front and rear tires have opposite tread patterns? ? Ramblings of a Singapore Biker Boy

Further, deponent sayeth not.



Well . . . maybe just ONE more link (2-minute video):

And . . . why not a quotation from Dunlop Q's and A's?

Why are some front and rear patterns reversed? What about channeling the water?

Many Dunlop motorcycle tire patterns have “reversed front patterns” compared to rear, because different forces act on front and rear tires. We test all Dunlop tires for satisfactory wet performance in the direction as indicated on the sidewall. It is important to always mount the tire in the correct direction of rotation as indicated by the arrow on the sidewall.

All this, and . . . AFAIK no LEGAL requirement demands mounting tires according to their manufacturer's direction-of-rotation arrow; free country, your bike; mount as you choose!

 

[Tom Schmitz]

Wet performance is of minimal concern with a motorcycle tire. The round shape of the tire presents a canoe-shaped contact patch to the road surface that quite naturally disperses water. Contrary to some conventional wisdom, a motorcycle tire cannot hydroplane under any rideable condition.

A motorcycle tire is completely dissimilar from a car tire, which presents a rectangular contact patch to the road surface. Car tires, of course, will hydroplane with sufficient water and/or speed.

As far as front tire mounting that is not asymmetrical creating problems, the Kenda K761 will cup badly, refuse to turn in, and will follow any irregularity in the road. Its service life will be no better than the rear tire, about 9K miles. Flipped around, it will wear perfectly with no cupping, turn very well, be stable over rain grooves and pavement joints, and last well beyond 18K miles. A K761 that has been incorrectly mounted, and which has cupped, will stop cupping and begin performing well if flipped around. This is a tire I know well. The manufacturer recommends mounting it incorrectly, having the direction of rotation marking being the same as a rear tire.

The most common reason for motorcycle tire asymmetry is as described several times above. Both tires are responsible for acceleration forces, the rear being acceleration while the front is deceleration.

The front tire does not steer the bike at riding speed. Both tires steer the bike. Take any wheel and stand it upright. Roll it forward it will go straight. Lean the wheel slightly and push it forward. It will move in a circle and, if you can keep the wheel moving at the same speed, it will constantly turn in the same circle. The bike is turned by leaning it over on the tire, a lean which is initiated by a slight turn of the front tire in the opposite direction of the turn. Both tires do the same job except for the direction of the acceleration forces.

I have never seen the mounting configuration, though, to be anything other than as Paul states.

 

[Voyager]

Wet performance is of minimal concern with a motorcycle tire. The round shape of the tire presents a canoe-shaped contact patch to the road surface that quite naturally disperses water. Contrary to some conventional wisdom, a motorcycle tire cannot hydroplane under any rideable condition.

A motorcycle tire is completely dissimilar from a car tire, which presents a rectangular contact patch to the road surface. Car tires, of course, will hydroplane with sufficient water and/or speed.

As far as front tire mounting that is not asymmetrical creating problems, the Kenda K761 will cup badly, refuse to turn in, and will follow any irregularity in the road. Its service life will be no better than the rear tire, about 9K miles. Flipped around, it will wear perfectly with no cupping, turn very well, be stable over rain grooves and pavement joints, and last well beyond 18K miles. A K761 that has been incorrectly mounted, and which has cupped, will stop cupping and begin performing well if flipped around. This is a tire I know well. The manufacturer recommends mounting it incorrectly, having the direction of rotation marking being the same as a rear tire.

The most common reason for motorcycle tire asymmetry is as described several times above. Both tires are responsible for acceleration forces, the rear being acceleration while the front is deceleration.

The front tire does not steer the bike at riding speed. Both tires steer the bike. Take any wheel and stand it upright. Roll it forward it will go straight. Lean the wheel slightly and push it forward. It will move in a circle and, if you can keep the wheel moving at the same speed, it will constantly turn in the same circle. The bike is turned by leaning it over on the tire, a lean which is initiated by a slight turn of the front tire in the opposite direction of the turn. Both tires do the same job except for the direction of the acceleration forces.

I have never seen the mounting configuration, though, to be anything other than as Paul states.

Motorcycle tires can and do hydroplane. Yes, the round profile raises the speed a little, but F=ma still holds. The harder you try to accelerate the water out of the way, the harder it resists.

https://youtu.be/6TRCroy3DKs

 

[pdwestman]

Damocles, If those are the 'imprints' of the tires left on the ground, then all 4 of your most recent text diagrams are still in the scoop shovel direction.

The front tire vees are being filled with dirt, sand, gravel (and yes even water Voyager) into the center-line by forward motion, and even fuller during braking.
The rear tires vees are acting more like mini sandpaddles, than tractor tread which squeeze the softer terrain out to the sides during driving force.

So again I suggest your illustration illustrates the 'poorer handling / poorer mileage' direction of installation of both front & rear tires.

 

[DPelletier]

I see alot of intelligent people making logical and reasoned arguments about a topic on which little actual evidence exists! ;-)

I will suggest that the best tread pattern direction is influenced by a number of factors, including;

- the exact make, model and size of tire in question
- the weight of the load on the tire
- the type of surface
- whether the surface is wet or dry
- the surface and tire temperatures
- the speed of the bike
- the tire pressure


......I'm not convinced that the "best" direction may not vary depending on these variables. I suspect Voyager is correct in that it probably doesn't make a ton of difference in most cases and I also would put the point of the Vee first on the front on a street tire.....OTOH I think Paul's diagnosis of the front D606's issues when mounted as recommended (open end of Vee facing forward) likely contributes to it's "less than confidence inspiring" performance on gravel. Tom correctly notes the different acceleration forces on the front vs. rear... Dual Purpose bikes like the KLR are used in such a wide variety of ways (which is the point of them) that determining what's best in any sort of blanket statement may be imprudent.

JMHO, carry on. :grin2: and since I run the omni-directional D606 rear and MT21 front, I guess it doesn't impact me much!

Dave

 

[Tom Schmitz]

Motorcycle tires can and do hydroplane. Yes, the round profile raises the speed a little, but F=ma still holds. The harder you try to accelerate the water out of the way, the harder it resists.

https://youtu.be/6TRCroy3DKs

You've quoted an extreme case to make your point. A very extreme case, apparently having missed "under any rideable condition". Would you ride headlong at 60mph onto a section of pavement covered in 6 inches of standing water? A brick won't survive that. Let's stick with the practical example of 60mph in a torrential downpour, a condition under which a car tire will hydroplane but a motorcycle tire won't.

Citing f=ma to dispute an assertion in fluid mechanics doesn't work, either.

 

[Damocles]

Continental TrailAttack dual-sport tires, direction of rotation towards the left of the frame (counter-clockwise, as viewed):



Enlargement for better view of direction-of-rotation arrows:



Unchanged arrangement of tires; better view of treads (notice respective orientation of front and rear tread Vees):



Tire label:



My perception: Front and rear tire tread Vee orientations are reversed, if manufacturer's suggested direction-of-rotation is followed. YMMV!

 

[pdwestman]

Yes, and the imprint on the ground with the Conti Trail Attack front tire is Tops of the vee make contact 1st and the center Tip of vee contacts last. So the pattern acts like more of a wedge, instead of a scoop.
Front Conti Trail Attack tire traveling to the right will leave this basic imprint on the ground >>>>>>>>>>>>>>>>>>>, to wedge the water, dirt, sand and gravel away from the center line.

When the tire is viewed from in front of the bike the vee will appear up-side down ,/\,

 

[Damocles]

Front Conti Trail Attack tire traveling to the right will leave this basic imprint on the ground >>>>>>>>>>>>>>>>>>>, to wedge the water, dirt, sand and gravel away from the center line.

But the front Continental Trail Attack shown in the images above will never be, "traveling to the right," unless the motorcycle has a reverse gear or the tire is mounted, "backwards" from the maufacturer's direction. I tried to point out, the direction-of-rotation arrows in the images result in counter-clockwise rotation, rolling toward the left of the frame.

Now . . . is the orientation of the Vees reversed, comparing front and rear tread patterns, if mounted in compliance with the direction-of-rotation arrows?

Did Continental prescribe in error (a serious possibility, IMHO)?

Considerations may be moot. Although designated a, "dual-sport" tire, the Trail Attacks may be somewhat pavement-biased, seems to me.

 

[pdwestman]

Ok, so traveling to the left the Front Conti Attack imprint on the ground looks like this <.

I'm out, We have confused the newer members enough.

 

[Tom Schmitz]

Erm, the older ones, too.

 

[Voyager]

You've quoted an extreme case to make your point. A very extreme case, apparently having missed "under any rideable condition". Would you ride headlong at 60mph onto a section of pavement covered in 6 inches of standing water? A brick won't survive that. Let's stick with the practical example of 60mph in a torrential downpour, a condition under which a car tire will hydroplane but a motorcycle tire won't.

Citing f=ma to dispute an assertion in fluid mechanics doesn't work, either.

You made a fairly extreme assertion that motorcycles can’t hydroplane under any rideable condition. Not sure exactly what that is, but motorcycles can and do hydroplane under rideable conditions as I’ve had hit happen. It dodsn’t take 6 inches of water. 1” will do fine at 70 MPH on the interstate.

F=ma is a fundamental concept in fluid mechanics. Even Wiki knows that.
https://en.m.wikipedia.org/wiki/Fluid_dynamics

The tire is accelerating the mass of water on the road and the force from doing so is exactly what reacts against the tire. Accelerate the mass hard enough and the force from the water will lift the tire off the road and will do so in many “rideable” conditions. Although, I guess many riders are already to ride in the rain so I guess for some any rain might be defined as a non-rideable condition in which case your assertion then holds. :grin2:

 

[Damocles]

I'm out, We have confused the newer members enough.

Erm, the older ones, too.

O.K.!

I now hereby concede: There will be PEACE in the MIDDLE EAST before I achieve consensus with this premise: The Vee orientation is reversed, comparing the front and the rear tire shown below, when mounted consonant with direction-of-rotation arrows:

 

[Voyager]

Ok, so traveling to the left the Front Conti Attack imprint on the ground looks like this <.

I'm out, We have confused the newer members enough.

But it is great fun! :grin2: