grumpus

Examine the pattern of the tread - if there's some directionality it will be in the form of chevrons, whether solid shapes or an arrangement of separate blocks or grooves. For smooth running on a paved surface you want the tip of the chevron to make contact before the sides, so the chevrons should be pointing forwards as you look at the tyre from above. This "might" also displace surface water to the sides. It is the direction for the rear tyre on dirt to dig in under traction, increasing its contact area. Reverse that for the front, so it digs in under braking. There is an argument for reversing those directions in soft sand because if the tyre digs in you'll just bury the wheel without gaining traction. IMHO YMMV

Crankycrank

+1. I think this answered the OP's question way back at post #3. If these are the OP's tires posted in another link then FBinNY's advice for mountain bike tires applies in my experience. The main thing is that the tires themselves will not fail no matter which direction they are mounted and if you really want to know the answer to what works best for traction try mounting them in different directions and test them out.

TC1

Now check the publication date. 1963.

Iride01 

So if I ride too fast going around a corner on a dry road and my rear wheel goes out from under me, then I guess I must have hydroplaned!

sweeks

Well, at least the paper doesn't catch fire!

sweeks

The date is irrelevant unless there is more recent scholarly evidence to the contrary.

TC1

So why do sneakers use softer rubber soles than dress shoes? So they can deform into the surface, and generate traction. Tires are not adhesive, and you can prove this to yourself with a simple test, if you like.

Because, as already explained, your vehicle's mass is fixed. And gravity is static. And the durometer of your tires is static ( within the constraints of one corner, anyway ). So something has to change, in order to prevent your tires from deforming into the surface -- otherwise they will continue to do so, due to gravity pulling them into the road surface.

No one here has offered any suggestion as to what that "something" might be, if it isn't hydroplaning.


Yes, exactly. If you go back and check that corner afterwards, you will find the black marks created by the liquid rubber on which you hydroplaned.

Yes, it is. Otherwise gravity would still be pulling down on your vehicle, and causing your tire to interface with the road surface, and developing traction. Gravity does not take holidays. It is always there.


Yes, they do. We didn't know this back in 1963 when that NASA paper was published, but we've learned more since then. Come on guys, I am not telling you anything that you should not already know.

Again, you are hydroplaning on liquid rubber. There is no other option, unless you turned off gravity.

If your tire can lose 25% of traction and not slide, you were not near the limit of traction in the first place, by definition. I am not claiming that all tires hydroplane all the time -- that would be ridiculous nonsense. I am explaining to you that all tires can hydroplane.

I most certainly did not refute my own argument. Cars do not "build tread", so restate whatever you were trying to write here, as this makes no sense.

I posted video of road bikes hydroplaning.

No one has yet offered any thing even resembling an explanation of how those videos -- not to mention a motorcycle travelling across a lake at bicycle speed -- are possible in this world that you imagine, where bicycles cannot hydroplane.

Until and unless someone, anyone, offers such an explanation, then I'm afraid you all are tilting at windmills. There exists video evidence of bicycles hydroplaning. That remains a very serious problem for all y'all who are claiming it cannot happen, and needs to be addressed.

CliffordK

That tire will be smooth soon enough!!!

With tractor tires, they say to mount with the chevrons pointing towards the ground in front so that the middle part contacts first. The theory is that it pushes the mud and water to the side to improve traction. Mounting them backwards pushes the mud to the middle and makes traction worse.

It should be similar for other types of tires, although perhaps to a lesser extent.

TC1

First of all, "scholarly" is not the only type of evidence. Quite a lot of professional research has occurred on this topic in the past 60 years, as no one should be surprised to learn.

And, again, we have video evidence of cycles hydroplaning -- which is the 800 pound gorilla in this particular room, who remains ignored.

I am still waiting for someone to explain how those bikes hydroplaned, if such is impossible. You have only three choices:

1. Insist that all of those videos were doctored
2. Explain the other as-yet-unknown phenomenon which caused the separation of tires and road, and which allowed that motorcycle to travel across a lake
3. Admit the obvious, which is that bicycles can and do hydroplane

TC1

That is not always the case. For a counter example, check the Schwalbe Rocket Ron:

https://www.jensonusa.com/Schwalbe-R...ound-29-Tire-3

It is directional, but one would be hard-pressed to guess the proper direction by inspecting the tread pattern.

Russ Roth

Yes, but again, when operated near the limits, it doesn't take hydroplaning to allow the slipping, it just has to have something reduce the level of friction for it to all go awry. Even a damp surface isn't wet enough to hydroplane but the reduction of available dry surface is enough to exceed the capabilities of the tire. In which case, its just slipping, that's all, it doesn't have to be more than that.

Actually there aren't typically black marks, its a skid, not burning out. Take sandpaper and scrape a board over it, would you suggest the streak left on the paper is liquid wood, I'd hope not, that would be a stupid answer. If left alone the board shouldn't move, yup, gravity always works, but it slides across the paper when a force is applied, the same thing that happens when a car or bike moves across pavement through a curve. The sideways force of momentum through the curve applies a directional force that can exceed the downward pull of gravity. Maybe with the speed of a car, not not with a bike tire, when a tire slips out on a curve it isn't slipping on liquid rubber. Rubber liquefies at (quick check of the properties of rubber) 350 degrees fahrenheit, a temp bike tires aren't hitting when they slip out on a curve. You lose sight of momentum and applied force when you jump to the assumption that a slip out can only occur on liquid or if gravity turns off.

look up aquatreads.

Motorcycle tires are significantly wider than bike tires, and again, just cause something slips in the wet doesn't mean its hydroplaned, it just slipped because it exceeded its ability to adhere to the pavement. I've yet to see anything in those videos that proves the bikes hydroplaned, just that its claimed. Show me a bike riding across the surface of a lake the way a high speed car or even more so, a snowmobile can and you will be showing hydroplaning. Anything else is just proof that the tires exceeded the ability of the rubber and pavement to adhere to each other.

grumpus

There's no need for a "rule of thumb" when mounting tyres that have the intended direction of rotation marked on them, although you may want to try them the "wrong" way to address a particular requirement.

TC1

General note, I started a new thread with proof that bicycles can hydroplane. This will be my last reply here.


Again, for the hundredth time, please do not try and attribute this behavior to unnamed magical forces. What -- exactly -- is the "something" you believe in, to which you refer in that sentence? If you cannot name it, or explain it, I am inclined to quote Steve Wonder at you: "When you believe in things, that you don't understand, then you suffer."


Same thing.

They don't "build tread".

And motorcycles are many times heavier, resulting in similar tire psi on the ground.

For the hundredth time, how? Without a change in gravity or mass or pressure, how does this occur? Please do not attribute it to magic. I would like you to specify the physical phenomenon responsible for a tire ceasing to interface with the ground beneath it.

Are you kidding me? How is a motorcycle travelling across a lake not hydroplaning? I'm sorry, but I think you are completely divorced from reality.

Ibid.

zandoval 

Tread usually

points in the direction of travel...

TC1

I know, that's why I pointed out that your suggested rule of thumb has exceptions.

JoeTBM 

Move on, you have already beat this dead horse to oblivion

shelbyfv

Apparently he can't help himself.

JoeTBM 

I very rarely do this but I feel an "ignore" option coming on strongly.

DiabloScott

Confirmed:

(later)
The physical phenomenon he's looking for is called "lubrication". He's essentially claiming that lubrication is the same thing as hydroplaning. While there are some similarities at a microscopic level, hydroplaning implies that the distance between the two surfaces is large enough that they don't even affect one another. An example would be a vehicle that enters a puddle that covers both paved road surface and a grassy shoulder. If the vehicle hydroplanes, it will pass over the pavement and over the grassy area with no difference in friction because it doesn't even sense the grass. If the vehicle doesn't hydroplane it will maintain contact with the pavement and slide with reduced friction to the grassy area where it will behave differently.

maddog34

look up:Tire CONTACT PATCH Pressure per SQUARE INCH of Contact " some time... then realize that you are wrong. the principles involved are Identical... and where the rubber meets the road, the "round profile" bike tire is no longer ROUND... etc.

do you also think bike brakes and automotive brakes aren't the same too?

DiabloScott

It's the difference between a belly flop and a vertical dive.

More strawman arguments

dedhed

​​​​​​"One of the most commonly used equations for predicting hydroplaning was developed by NASA. This equation is also known as Horne’s hydroplaning equation [7] which is valid only for smooth tires with limited groove and tread design."

Horne is still in use today.

​​​​​​https://vtechworks.lib.vt.edu/bitstr...per_REVIEW.pdf

TC1

Grumpus and I were having a brief side chat about whether or not one can reliably determine intended tread direction by visual inspection of the pattern. That's not directly related to the main issue that I have been educating y'all on, hydroplaning.

If you were offended that I replied in that side conversation, well, get over yourself. Same applies to @shelbyfv.

And, for the record, the horse is still kicking, because several people here still cannot understand that bicycle tires can, and do, hydroplane -- despite proofs from NASA and NHTSA, and video evidence.

TC1

You may be interested in the new thread, where that is discussed in more detail -- specifically the fact that NASA's equation proves bicycles can hydroplane.

TC1

Recommend that you do some reading about how thin "large enough" is, in this context. "Large enough" is still microscopic. You are getting closer to understanding the concept, though, which I commend -- unlike some of your compatriots here.