Trying to determine the proper tire direction. There is no direction arrow on side wall. The pic is shot from the top, with derailleur on the right side.

I don't see a pic. But what I've found, generally, is if there is a printed logo on the sidewall, it goes on the right (gears) side.

Your photo didn't link, and if I remember the rules, will not until you have 10 posts.

However, here's some help.

Most bike tires are not directional in any way. For those that are, the right direction depends on the intent. On a rear mtn bike tire the intent is to get the most push off in soft sand or mud, so mount the tire so the "harder" side of treads are to the rear on the bottom (forward on top). Reverse this in front so you get the maximum bite when braking.

For road bikes tread is mainly cosmetic, though it has some effect when the road is dusted with wind blown sand. Typical road treads often have herringbone type treads, modeled like those on car tires. The logic is that the point hits first and wedges water outward as the tire rolls. This doesn't matter on bikes, since water isn't an issue, but for cosmetic purposes mount so the herringbone points forward on top.

Yes it does, unless you are proposing that bicycles inhabit a different physical universe from automobiles, and everything else that utilizes tread.

Bicycle tires are essentially different from car tires in an important way. See what Sheldon Brown had to say about this.

There is plenty of documentation for why road bike tires don't need tread, and we've done fine without for a century or so.

However, we don't need to argue that here. Instead, feel free to challenge the specific advice I offered the OP.

Or better yet, offer your own opinions in answer to the OP's question.

No, there is not, which is why so many bike tires have tread.

No, they are not, and the venerable Mr Brown is wrong on that topic, of which we have video evidence.

You Tube

Bicycle tires are subject to the same physical laws as automobile tires, and there is nothing about them which changes the fact that water is incompressible and once the vehicle reaches a speed that exceeds the tire's pumping threshold, the tire will hydroplane.

The only difference is that bicycles generally lack the horsepower to achieve that speed, unless gravity-aided.

From someone that posts a thread-
Have You Ever Broken a Frame Removing Headset Cups?

Ignore List

Is this the pic you intended to link?



https://www.bikeforums.net/g/album/29735669

10 post and maybe a day later you should be able to to post pics and links. Till then just let us know you put a pic in the Gallery here on BF and someone can find it and post it for you.

I wouldn't sweat the tread direction if they don't have an arrow on them. Even if they do, it's not a really big deal. I think you are good with the current direction for mud and dirt when off road.

I would mount that tire as shown rotating down. If it was smooth or had a symmetrical pattern then it wouldn't matter.

And you don't think that's a material consideration?

In any case, it's interesting that while you're the most invested in arguing the importance of tread, you're the only one here who hasn't offered the OP any help.

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Word of advice, which I'm sure you'll ignore.

Your new here and don't know the players. Some are extremely knowledgeable on bikes, some are engineers, physicists, chemists, or other professionals well credentialed to discuss technical subjects.

You would be well advised to listen more and argue less until you know who's who, and what they know

It becomes material as soon as one crests a hill. If you never do that, it remains theoretical.

I corrected the erroneous advice that OP received, specifically that bicycles cannot hydroplane.


I may be new here, but I am not new to bicycles or physics, and I am extremely knowledgeable on both topics. Perhaps you were under the impression that everyone who knows anything about those topics participates here, but I assure you, such is not the case. If you can only argue against my point by attacking me and the age of my account, well, I think we both know what that means. Instead of resorting to ad hominems, why don't you explain how bicycles violate all known laws of physics, and/or why I can provide video evidence supporting my position?

Again, if you can only judge a position by the author's name, you probably don't understand the topic sufficiently.

Well they don't of course. Auto tires are wide and have a flattish profile and they can hydroplane because the water can't out of the way fast enough. Bicycle tires could hydroplane if we're talking really wide ones like 4" with a flattish profile, but your basic road bike tire is too narrow and too round for that to happen; in fluid mechanics terms, the two do not have dynamic similarity so using one to model the other is invalid. The videos you posted show slippery roads and high resistance from riding through deep puddles, not hydroplaning.

More to the OP's point, no tread in any direction would've prevented any of those crashes.

"Slippery roads" are hydroplaning. Otherwise, you need to provide some alternative explanation for why gravity ceases to function, and allows a tire to lose contact with the surface.

You are apparently a few decades out of date with your understanding of the interface between rubber tires and road surfaces. It was once thought that rubber somehow "gripped" pavement, and provided the traction we all rely on. The advent of superior inspection tools, like electron microscopes and others, has improved our knowledge in this field, and we now understand that rubber tires provide traction by deforming into microscopic imperfections in the surface. And that gravity provides the force required to cause that deformation. This is why dynamic weight distribution, and the control thereof, is so critical to performance on both two and four wheels.

So, what you call a "slippery road" is, in reality, we now realize, just the hydroplaning effect of a potentially microscopic layer of water preventing the rubber from deforming into those imperfections.

This is obvious, in hindsight, because there is no other mechanism by which gravity could be disabled, in order to allow a tire's rubber to stop interlocking with the road surface.

The same effect occurs without water, when a tire is pushed beyond its limit, and it begins to melt. A thin layer of liquid rubber results, and behaves just as water does -- suspending the tire off the surface, and preventing tractive force from developing. This is how you leave skid marks on your fixie, or do a burn out in your Challenger.

I recommend that you (general) stop spreading obsolete and inaccurate information on this forum.

Oil residue, silt, leaves, painted lines.

So, Which way should the OP install them?

All of which interfere with the previously-described tractive mechanism. Oil, in particular, is evidence of hydroplaning -- if that phenomenon were impossible, tires wouldn't slide on oil, either, they would simply pump it out of the way.

Whichever way the manufacturer intended, if any.

That's a very different question from misleading OP into believing that hydroplaning is impossible on a bicycle. The latter is dangerous and inaccurate "advice", and I would've thought this august forum would be opposed to the spread of such, which is why I corrected it.

If, OTOH, spreading dangerous advice is what the cool kids do here, please just let me know that is the MO.

Actually you just gave an opinion, which isn't the same as correcting something.

Physics are not a matter of opinion, and the mechanics of the rubber/road interface are pretty well-established science at this point.

Video evidence of precisely the phenomenon in question occurring, and being decidedly not impossible, is also not an opinion.

You keep mentioning physics and such. Your opinion might be better received if you posted your qualifications. People tend to respect informed opinions.

Again, I am not asking you to believe in my opinion. I am explaining demonstrable fact to you. If you are unaware of physics, that's a shame, but that does not change the science.

If you like, you can remain ignorant of physics. That is your choice. Or, you can watch this video of a cycle traveling across a lake at ~30mph.



Also, for the record and as I already explained, if you can only judge an argument based on who is making it, then you simply are not sufficiently informed on the topic at hand. In fact, that is a popular logical fallacy called "argument by authority". Authorities can be, and often are, wrong -- as recently shown quite famously by the realization that the conventional wisdom regarding the efficiency of skinny, high-pressure tires was dead wrong, despite being believed by almost everyone for decades.

You're stretching the definitions and overstating the effects to make your point. While it is true that the tires deform into the imperfections in the pavement improving the grip it isn't true that that's the only source of the grip, as rubber is a high friction substance that can find grip on smooth surfaces just not as much. Liquids like water and oil can reduce this friction and make it easier to crash. This means when wet the tires don't grip the smooth areas as well and it also means that the water in the imperfections can't be sufficiently displaced (water can't be and doesn't have to be compressed, tires cover small areas and water can be displaced throughout the road surface) to create optimal grip between the surface making the tires less capable of holding. But that isn't the same as hydroplaning where the tires are using the water as the road surface and are no longer in contact with the actual road.

OP, the tires in the pic have a center tread that has lines coming in and pointing towards the way forward.

Good luck catching flies with vinegar, [MENTION=567429]TC1[/MENTION].

My point was made about 20 comments ago, when I posted video evidence of this phenomenon. Now I am just explaining the effect to folks who don't understand.

By what mechanism is this alleged "grip" generated? Why does it cease to function when load is removed from the tire?

If you believe that hydroplaning a bicycle tire is impossible, explain what is causing many of the tires in those previously-posted videos to wander laterally underneath riders who are travelling in a straight line. None of this magical "grip" that you believe in is even necessary for a tire to roll straight, and yet, these riders -- who are all quite talented -- cannot keep their tires rolling straight.

Why, exactly? And be precise.