TC1

What vinegar? I have been as polite as can be. It isn't my fault that no one else participating in this thread is familiar with how tires work.

Should I allow misinformation to spread here just because a number of participants seemingly dislike being corrected? I suggest not. Frankly, I do not really care if several of those participants learn about the tire/road interface in this thread, or not -- I just want them to stop providing inaccurate information to people like OP, because that, to the best of my knowledge, is not what this forum is for ( although I stand ready to be corrected, if ********ting is the order of the day here ).

79pmooney

I've been flipping fix gear wheels around for years. Used to run the tire labels to the left. I have yet to notice a difference. Road bikes ridden in all weathers except I didn't start flipping fix gear wheels until after I left the Michigan and Massachusetts winters.

You might be right, that tire direction matters more than just semantics. But if so the difference under my threshold of observation.

DiabloScott

Are you telling me that coefficient of static friction is an obsolete concept? Maybe my knowledge is out of date. Wait let me Google.

Nope, it's still a thing. And it's a smaller number for wet or oily surfaces with rubber, than it is for dry ones. The tire does not lose contact with the surface (that WOULD be hydroplaning), it just changes from static/rolling friction to sliding friction. It is measurable and can be used to predict the behavior of moving objects.

79pmooney

So when I slip on a kitchen spill, I just hydroplaned? I've slid out on slippery roads at under 10 mph. Pretty sure hydroplaning wasn't the issue. Now tire tread compound can make a huge difference. A certain model and year(s?) of one tire dumped me on wet leaves and bricks a few times. No+w that same tire served me well (other than being a buzz killer on mountain descents - I went so slow - by not picking up a single goathead in a week, Quite an accomplishment. They were flatting others on a regular basis, I was completely naive and did zero to avoid them.

TC1

You are missing the point. Hydroplaning is precisely the reason why those wet or oily surfaces appear to be "slippery". It is the reason why the tire stops rolling and begins sliding.

"Hydroplaning" does not always mean completely losing control and sliding for tens of meters ( like this unfortunate fellow whose exploits were previously posted ). Sometimes hydroplaning is far less dramatic, and just causes a tire to slide millimeters -- but it is still hydroplaning. Sometimes a rider with excellent handling skills can even keep a hydroplaning bike upright, as we see in some of those others videos -- but it is still hydroplaning.

Again, there is no other option. A rubber tire is pressed into the road surface by gravity acting on the mass of the bike and the rider. On this much, I hope we can all agree. Traction is thereby developed by that pneumatic tire deforming into the microscopic irregularities in the surface. Again, this it not a matter of opinion, it is established science.

So, what are you proposing causes a tire to stop rolling, and begin sliding? Something has to stop it from deforming into those irregularities. What, precisely, does that, in your imagination?

Or, to take the opposite tack. How, exactly, is the video above of a motorcycle travelling across a lake at around 30 mph possible, if it is impossible for bicycle tires to hydroplane?

With all due respect, someone needs to concoct a plausible explanation for that video, and the others, or y'all need to stop wasting my time arguing about known physics supported by multiple pieces of video evidence.

TC1

Quite possibly -- depending on your footwear.

Why, exactly?

Yes, it can, because rubber compounds have different hardness ( or softness, if you prefer ). This is called a Durometer rating, and the lower your rubber's durometer, the softer it is, and the better it deforms into the road surface irregularities, and the more traction you have, as a result. Unfortunately, TANSTAAFL, and extremely soft rubber tears and melts easily, so those tires typically have short lives, and don't tolerate abuse well.

DiabloScott

Oh I understand the point you think you're making, I just think you're incorrect. The very definition of hydroplaning is loss of contact between the tire and the surface; the tire floats above the surface...this does not happen in a slide.
I also think you're conflating two points - the tread on a narrow bicycle tire has a very minimal ability to channel water out from under it the way tread on car tires can - which can be a factor in hydroplaning.
In your most recent video, it looks like the rider locked up his wheel, creating a slide. Locking and sliding happens much quicker with worse consequences on wet roads because the coefficient of static friction is less than it is on dry roads.

TC1

Yes, it does happen. In fact, it __must__ happen, unless you have an alternate explanation for why the interlocking between the rubber and the road ceases. Do you have such an explanation, sir?

As long as the rider is still aboard the bicycle, and as long as the bicycle still has a mass, gravity must necessarily still pull them both into the Earth. So unless your tire pressure somehow skyrockets while you are riding, then your tires are still going to interface with the road until and unless something separates them.


Again, why is the coefficient of static friction less?

That's the point you are missing. Hydroplaning can be a motorcycle across a lake. It can also be a microscopic layer of liquid -- technically only one molecule of depth is required -- which is not even visible to the naked eye. But the physics remain the same, due to the incompressibility.

Again, there is nothing else which can cause the reduction of friction -- unless you are proposing that the rider and bike have their combined mass drastically reduced while in motion, which is a radical suggestion, to say the least. Or perhaps you believe that gravity fails, every once in a while.

DiabloScott

What do you suppose happens in a dry skid?
1. Hydroplaning and sliding are two very different things. Wet tires are in contact with the wet road, hydroplaning tires are not.
2. Bicycle tire tread doesn't help with either of them; this was the original argument you attempted and you seem to have dropped it.

It is a fact that small amounts of water can INCREASE the coefficient of friction for certain material combinations. You must explain that and your "one molecule" statement.
You are making strawman arguments about mass and gravity and tire pressure.

JoeTBM 

@TC1 I don't think you are making any friends here

TC1

There is no such animal. When a rubber tire skids across pavement, it liquefies itself and creates the thin layer of liquid which -- as previously explained -- interferes with the rubber-road interface. That's what a skid mark is.


I am afraid you are wrong, they are not different. And you neglected to explain why or how the tire-road interface ceases to function -- if not due to hydroplaning.

You also neglected to explain how any of those videos clearly showing hydroplaning cycles are possible within the physical world that you imagine exists.


My original argument was actually that bicycles can hydroplane. That has been proven beyond a shadow of a doubt ( not by me here, by decades of study and investigation and experience ).

The separate question of whether tread design can prevent that is not one I have addressed. It certainly can, but that is not my point at all. My point is that people need to stop parroting 1960s ideas about bicycle tires being immune to hydroplaning, when nothing could be further from the truth.



Your evidential link doesn't seem to have come through, first of all. Second, we are talking here specifically about rubber tires and pavement -- not some unspecified combinations that are irrelevant to the topic.


This is beneath you. This is a discussion about physics, so mass and gravity and pressure are anything but strawmen. Do better.

TC1

Well that's too bad, I guess. How do you propose that I remedy that? Should I adopt ideas that are proven to be mistaken by both science and evidence?

I don't need new friends that badly, nor do I particularly want such uninformed friends.

JoeTBM 

It is not up to me to tell you how to make friends, I was just observing this thread that went off topic.

I make no claims of being an educated person, just an ordinary simple guy that likes to fix bikes and help people where I can.

TC1

And that's all I'm doing here, too.

To my surprise, I appear to be the only participant in this thread -- hopefully not in the whole forum -- who has kept up with science in this area. So when I read someone's demonstrably false claim about bicycles and hydroplaning, I corrected it, just to stop the spread of that ancient misinformation.

For reasons not entirely clear to me, some folks here cling to that misinformation like a baby to a breast, even in the face of incontrovertible evidence. Or they are intentionally deceiving other users, again for reasons I cannot speculate on.

But I will keep trying to help people, at least until I am kicked out by my new non-friends.

JoeTBM 

You are not going to bait me...... move on

dedhed

​​​​​​https://ntrs.nasa.gov/api/citations/...9640000612.pdf

JoeTBM 

shelbyfv

Unfortunately, autodidacts can't know what they don't know. A couple of responders have actual credentials, yet this fellow twists, turns and remains aggressive in what he thinks he's learned from his YouTube videos. Those of us w/o the background to independently re-invent the bike tire have to choose whom to believe. My belief is that OP need not fear hydroplaning, whichever direction he installs his tires.

Trakhak

From this page:

That is a very interesting question as I designed and developed bicycle tires for a couple decades. I will assume going full speed (60 mph +) in a straight line on a paved road, on 700 x 28c tires (which is today’s norm/average road bike size). I will say “no”, because the contact patch is just too small with all the weight of the bike and rider bearing down on the two tiny contact patches where water easily gets displaced.

I will add, that a complete slick tire actually works better, then a tire with any type of tread pattern, again assuming the bicycle is going in a straight line at full speed. Now once the rider starts to turn, that is a whole different story for the tire contact patches to maintain grip on a wet road. This is where tire compound, air pressure, and casing construction comes into play, and some combinations will grip better then others, but still hydroplaning is not a factor.

Moe Zhoost

Time to close this thread. No doubt the OP has moved on.

Robert7659

The tread must take water from the center and drive it out the sides. Look at the tread and try to imagine the tire rolling, tracing the path the water would take. If the tire is rolling the wrong way the tread will pick water from the sides and drive it inward to the center.

grumpus

Cars can aquaplane, bicycles can't, so there's no need for a cycle tyre to clear water in the same way.

Russ Roth

friction, force that resists the sliding or rolling of one solid object over another. Frictional forces, such as the traction needed to walk without slipping

If the tires are already operating on the edge of their capabilities, why do they have to hydroplane in order to loose just enough of their traction to no longer grip the road? Does this mean when I take my Miata around a 30mph mountain curve at 70 and the car slides sideways a couple feet I'm hydroplaning? Do, it means I've exceeded the grip of the tires, if I hit a wet spot with one wheel I've reduced the grip of one tire, still not hydroplaning. Why it can happen can be related to many things including wind, surface irregularities, and deeper sections of wet forcing the tire to skew as it moves through the water.

1. Don't know what roads you ride, but mine don't rely on microscopic irregularities, blacktop just has irregularities.
2. If the tire stopped its cause the hit the brakes, does this mean when I skid my tire out on a dry descent I'm hydroplaning, again, no, I've just succeeded in exceeding the coefficient of friction, wet does it sooner. Again, doesn't mean that the tire is completely riding on water. You've gotten nitpicky about the details, but hydroplaning has water substituting as road surface, yet even a loss of 25% of the traction of the tire still leaves 75% in contact, ie not hydroplaning, and still past the limit of the tire to hold.

You refute you're own argument here. Durometer doesn't matter when hydroplaning, that's why cars build tread to stop it, it cause the car is no longer attached to the ground but the surface of the water instead. Durometer does matter, because at your microscopic level some of the water is displaced allowing the softer rubbers to contact the pavement maintaining better grip but the wetter and faster things are the less that can be displaced reducing the level of actual grip. Road bikes don't hydroplane. I hit a puddle at 45mph, if my ass wasn't back I'd have gone over the handlebars because the tire cuts in and slows rapidly.

sweeks

Yes, I notice pencil erasers melting as I use them.

shelbyfv

^^^Cause or effect?