I came off

[Pale Rider]

A slick tyre offers marginally more grip in the wet - on a hard, solid, surface - than a treaded one because there is a tiny bit more tyre in contact with the road.

Tread can help on loose surfaces, such as cinder track.

Compound comes into it, the tyre maker could produce a tyre that gripped better in the wet, but it wouldn't last long in the dry.

Schwalbe has a new four seasons tyre, but the tread on it is aimed at light snow and mud.

http://www.schwalbe.com/gb/newsreader/schwalbe-marathon-gt-365-the-all-year-marathon-gb.html

 

[Yellow Saddle]

Like most people with a view on this, I've read Sheldon's comments before. They still aren't going to settle the longstanding disagreement on the effects of tread for real-world road cycling.

Start a new thread on this, post your hypothesis and we'll discuss.

 

[PhilDawson8270]

A slick tyre offers marginally more grip in the wet - on a hard, solid, surface - than a treaded one because there is a tiny bit more tyre in contact with the road.

Unfortunately not really true. Surface area does not affect friction directly.

 

[jonny jeez]

Here, watch as I slew myself across a road


View: https://youtu.be/TEqLKiRfeOs


Please note = I don't think I swore

Enjoy

One of the most shocking videos I've seen in a long while. How can anyone go out in daylight with cables that don't match?


Oh, sorry about the fall, hope you heal up quick.


Now go swap those cables 100 times

 

[Moodyman]

I understood that it was the road that gripped the tyre. I.e weighted tyre deforms and the coarse surface digs into tyre and creates friction.

So I'm in the no tread camp.

 

[PhilDawson8270]

Interesting thread heist. I found this too:

http://www.bretonbikes.com/homepage...he-importance-of-tread-pattern-on-cycle-tyres

I took this whole thing with a pinch of salt when he fell into the trap of more rubber = more grip. That is not why race cars use slicks. It is for heat management.

Treaded tyres will very quickly overheat in dry conditions when used hard on a racetrack. During a lot of off season winter race track session you will see lots of people using tyres designed for the wet when it's dry. Since the tread movement increase temperatures, and the compound is generally much softer and thus becomes much hotter for the same loads.

He also only touched on wet and slick, yes wet is designed to clear water. But he totally missed the intermediate, which is cut into blocks. To help create heat in the tyre when the track is cold and wet, but with no standing water to disperse.

 

[Salty seadog]

Good article.

For once.

It had your favourite subject to blame, 'marketing' i happen to agree but I know I fall for it too, I'm sure we all do at times.

 

[Pale Rider]

Unfortunately not really true. Surface area does not affect friction directly.

This illustrates the danger of applying theoretical physics too closely to a real world situation.

The experience of riders and drivers alike is that wider tyres offer more grip than narrow ones - the greater the contact area, the more the tyre grips.

And, going back to treads against slicks, Schwalbe give you an argument:

"On a normal, smooth road, even in wet conditions, a slick tyre actually provides better grip than a tyre with a tread, because the contact area is larger."

http://www.schwalbe.com/gb/profil.html

 

[PhilDawson8270]

This illustrates the danger of applying theoretical physics too closely to a real world situation.

The experience of riders and drivers alike is that wider tyres offer more grip than narrow ones - the greater the contact area, the more the tyre grips.

And, going back to treads against slicks, Schwalbe give you an argument:

"On a normal, smooth road, even in wet conditions, a slick tyre actually provides better grip than a tyre with a tread, because the contact area is larger."

http://www.schwalbe.com/gb/profil.html

The inevitable appeal to authority

I did actually email Schwalbe a while back regarding the validity of that statement and asked them how it is possible. They never did reply, despite several reminder emails.

https://www.cyclechat.net/threads/in-praise-of-titanium-and-spa-cycles.183930/post-3804044

 

[Pale Rider]

The inevitable appeal to authority

Presumably, that's a smart-arse non response, but I genuinely have no idea what it means.

Anyhow, people can make up their own mind from experience and what the tyre makers say, setting that against your view.

 

[raleighnut]

Vittoria Rubino's 23c, no tread so to speak, lethal in the wet as i found out.

New Winter tyres are Schwalbe Marathons with a decent tread (I hope)

I'd watch Marathons for grip when they're new, once they are 'scrubbed in' they grip well but they need a fair few miles on em.

 

[PhilDawson8270]

Presumably, that's a smart-arse non response, but I genuinely have no idea what it means.

Not a smart-arse response, but a tongue in cheek comment as this Schwalbe statement is regularly brought up as evidence when this topic is discussed, and I was certainly expecting it when I made my reply

Appeal to authority, is when a statement from a source of perceived authority is used as evidence that the statement is correct.

In this case, the assumption that Schwalbe's statement about tyres is correct, as they are in the industry of selling tyres.

Their primary purpose though is to market, and sell the tyres.

As I say though, their statement does not stack up against physics too well, nor any academic source. Regardless of surface area (or contact patch), the coefficient of friction between the materials will remain the same.

http://www.physlink.com/education/askexperts/ae140.cfm

As that link elegantly puts it, if you increase the surface area, you also decrease the pressure, this exactly offsets the increase in surface area, thus results in no increase in friction. You would need to increase surface area, AND the pressure.

The assumptions in the standard model tend to fail when the object is small enough to dig into the other surface, this isn't at the tiny level of road tyres, but when you have knobbly tyres on a loose surface.

 

[ColinJ]

I haven't had time to study all of THIS discussion but it looks interesting and I will return to it later!

 

[HLaB]

Here, watch as I slew myself across a road


View: https://youtu.be/TEqLKiRfeOs


Please note = I don't think I swore

Enjoy

Ouchiees.

I found Rubinos towards the end of their life because there so hard wearing (can't remember a p'ture) were a bit skitty. Money was a bit tight when I had them so I lowered the pressure to mitigate the skittishness rather than buying a new tyre and never had a problem after that. What pressure are you running?

 

[PhilDawson8270]

I haven't had time to study all of THIS discussion but it looks interesting and I will return to it later!

A good discussion in that thread, with lots of very good points. Especially about friction not being simple, but I don't think it is directly relatable to a bicycle tyre, or most real world applications. After all the standard model behaves well when used in crash investigation, etc.

In my opinion, the biggest influence on grip on a road tyre is not the tread, but the compound.