Tread..............needed?

[mickle]

go on then

Physics and Maths A levels here and a Mechanical Engineering Degree

Painter's post and indeed Bonj's look right to me

I read the Sheldon and it was an eye opener to me but the tyre either opens a perfect contact to the road or it doesn't, and if it doesn't then tread does help

I find it hard to believe that all those bike shops are in on the lie and don't tell the truth to people that ask them about tyres

I was talked into some 2" City Slicker Fat Boys on an early MTB for commuting when they were the must buy bike and they ran fine but skated around something horrid in the wet, not skidded, waltzed

How does tread help? All tread does is reduce the contact area.

You give cycle shop workers too much credit.

Wet conditions do reduce grip whether you are riding slicks or treaded tyres or knobblies or bleedin tungsten studded ice tyres but a slick bicycle tyre cannot aquaplane.

 

[Smokin Joe]

The tread pattern on a car tyre will disperse water from beneath the tyre and aid grip. It cannot do that on a cycle tyre because the tread cut is not deep enough. You can see this by riding over a damp patch and then looking at the line left by the tyre on the dry road, no impression of the tread will be visible because the whole of the tyre has been in contact with the road and the water has not been channeled away.

If you look at the gaps between the tread cuts on a car tyre they are wider than the entire contact patch of a cycle tyre and that is enough to disperse the water to either side. Pro teams who ride on slicks do not change tyres when it rains and they have no trouble matching the performance of teams with treaded tyres.

 

[Alcdrew]

What about in snow? will slicks be better then something with a bit of tread to it?

Just asking as I bike to work year round, and this year is my first on 700 x 32slicks, Iam a little worried.

 

[asterix]

Although I agree that in most conditions tread is irrelevant on a road bike tyre, I think Tynan may have a point.

Should the road be coated with slimy substance denser, less displaceable than water than water, e.g. a film of mud or rotting leaves, a bit of tread may prevent the slippery substance lubricating the contact between tyre and road by cutting through it.

Certainly in normal years Autumn is a very dodgy time of year due to the over-confidence built up by months of dry summer roads.

 

[mickle]

Should the road be coated with slimy substance denser, less displaceable than water than water, e.g. a film of mud or rotting leaves, a bit of tread may prevent the slippery substance lubricating the contact between tyre and road by cutting through it.

How?

 

[mickle]

Ah the power of public service broadcasting. The grooves on car tyres are designed to displace water. If the water isnt displaced fast enough from the contact point the water will build up under the leading edge with nowhere else to go but under the tyre. At this point the tyre loses contact with the road. Its called aquaplaning. Slick tyres, those with little tread and wide tyres are most susceptable. Vehicle speed, vehicle weight and volume of water are also a factor. A light enough motor vehicle with wide enough tyres can drive on water if its going fast enough.
Cars can aquaplane at speeds as low as 30 mph, motorbikes at speeds as low as 60mph, given enough water.
Cycle tyres cannot aquaplane. They can lose grip if conditions are slippery, but slipping is not the same as aquaplaning. What keeps your bike lycra side up is grip. That grip is a function of the durometer or stickiness of the rubber, the area of rubber in contact with the road, the pressure exerted by the tyre over the contact area and the ability of the tyre to conform to the changing shape of the road surface (carcass flexibility).
All other things being equal, a treaded tyre will lose grip before a slick tyre.

Please dont start me off on the dynamics of off road treads, Ill be here all night.

 

[andy_wrx]

<pedant on>
What we're talking about is tread pattern.

All tyres have tread. Tread is the sticky rubber on the outside of the radial/crossply carcass of the tyre.
<pedant off>

Murray Walker could never get it...

 

[Smokin Joe]

<pedant on>
What we're talking about is tread pattern.

All tyres have tread. Tread is the sticky rubber on the outside of the radial/crossply carcass of the tyre.
<pedant off>

Murray Walker could never get it...

There's always a smartarse.

 

[Panter]

Thanks peeps. This has evolved into an interesting read, IMO anyway



What I'll take from this:

I don't have to worry about the lack of tread in wet conditions, but I still need to take it easy as the road will be slippery anyway.

I would guess that some sort of tread may help on a muddy surface by creating localised ridges with more weight on them which may push through the mud. Although they would also ultimately have a smaller contact patch so would lose out on grip the rest of the time.

I have renewed faith in my slicks and when they wear out, they'll be replaced with more slicks

Please dont start me off on the dynamics of off road treads, Ill be here all night.

I did have some MTB tyre questions, guess they can wait.................................................

Thanks again,

 

[Panter]

Ok, Tread pattern, sorry

 

[mickle]

<pedant on>
What we're talking about is tread pattern.

All tyres have tread. Tread is the sticky rubber on the outside of the radial/crossply carcass of the tyre.
<pedant off>

Murray Walker could never get it...

Yup. I stand corrected.

Ill get my coat.

 

[Tynan]

can't say I've found any of the arguments against tread convincing

either the water on the road interferes with grip or it doesn't, I'm hearing that it does

but the tread makes no difference whatsoever?

and the entire cycle industry is carrying on the lie?

 

[alfablue]

but the tread makes no difference whatsoever?

Well it will, in that if the tread pattern is at all significant it will reduced grip as the contact area is reduced, and nobblies used on the road will induce squirm, further impairing grip and handling.

and the entire cycle industry is carrying on the lie?

Yes...though "lie" may be a bit harsh. Many in the industry may be under the misapprehension that tread pattern is necessary, whilst the tyre manufacturers are probably not, but are probably just responding to what the market wants, however ill-informed.

Schwalbe are very good on "telling the truth" they say

Even in wet conditions, on a normal, smooth road, a slick tire actually provides better grip than a tire with a tread, because the contact area is larger.

They have a very comprehensive technical document (on all aspects of bike tyres) here

 

[John the Monkey]

I would guess that some sort of tread may help on a muddy surface by creating localised ridges with more weight on them which may push through the mud. Although they would also ultimately have a smaller contact patch so would lose out on grip the rest of the time.

Not quite the same situation, but I rode a piece of road between two farm tracks that was covered in sand, when I was in France. (It led to a lot of the little routes I was doing, so I went over it a lot). I had both my road bike, and the gite's knobbly tyred MTB to use - on the MTB, the grip was far more assured on this particular bit of road (on the slick tyred road bike, I could feel the back wheel losing grip on this part of the road).

 

[DustBowlRefugee]

I was going to go out on my road bike (with slick tyres) this morning but seeing all the wet fallen leaves I took the MTB instead (with knobbly tyres). Would I have been better off on the roadie?

Thanks
Mark