Tyre tread

[reohn2]

I read this earlier and wondered if it was worth a discussion:- http://janheine.wordpress.com/2014/09/2 ... ire-tread/

[mercalia]

my two pence worth. I want a tread pattern that rejects sharp objects and resists punctures. I think too often the tread funnels sharp objects into the non tread thin parts of the tyre and so get a puncture? Re side walls. I did once have City Marathons that had supple thin side walls and all I got for my effort was pinched tubes around the valve. I still have one , any one want it and live in London lol?

[Ayesha]

What he doesn't mention is the hardness of the rubber, the vulcanising process differences to produce a hard or soft rubber, and the different 'compounds' of rubber and synthetic that are out there today.
Inflate a tyre to 120 psi and put a Shore hardness tester on it. Although the tyre is inflated to 120 psi, a hard rubber will be identified from a soft rubber.
The soft rubber, no prizes for guessing, will grip better but wear quicker. It will also heat up quicker because of its elasticity.

Also, the woven casing has a bearing on how well the tyre handles a corner.

Tyre manufacturers go to great lengths to design and test tyres for specific purposes. I'd rather listen to the R&D engineers at Continental.

[Brucey]

well the last time we discussed tread patterns and wet grip, I expressed my preference for having a traditional rib and file tread pattern, on the basis that it did no harm in the dry and in the wet it gave me more confidence.

My argument was that I'd get more warning on tarmac before the tyre slipped away from me, and on perfectly smooth surfaces it was definitely beneficial. If this is what you feel then you will ride faster in the turns; all the grip in the world is a waste of time if you don't feel happy sat on top of it.

When I've skidded on perfectly slick tyres it has always been the same; almost no warning and then you are on your ear. This does not inspire confidence!

The mechanisms at work between a rough road surface and the rubber are pretty complex. It is worth noting that the file pattern allows the rubber to deform more (locally) than it would otherwise; this might fractionally increase Crr but it might also increase grip; if so, yeah, I'd be happy with that trade, in the corners.

cheers

[tim-b]

Hi

I don't think that tread patterns are significant on "normal" roads and, as Ayesha has already said, tyre design is complex with several variables
I have an article from Tour magazine dated 9/2007 where on a wet curve of radius 12.5m the Schwalbe Ultremo was one of the better performing tyres at a max achieved curve speed of 32.9km/h (the best was 33.2km/h). The Ultremo has no tread and was described by the testers as "predictable" http://www.conti-tyres.co.uk/conticycle/road_tyres/attack%20force/Resistance%20Fighters.pdf

http://www.schwalbe.com/gb/profil.html describes when tread is beneficial in more depth (excuse the pun) (EDIT>>) and it also answers the "Can a bicycle aquaplane?" question

I'm even less knowledgeable about the effects of confidence, but that will always be individual and subjective

Regards
tim-b

[albal1]

My view is tread on a tyre for road use is purely cosmetics, not enough speed to warrant a tread. Bold/slicks tyres just as good.

[Brucey]

I have an article from Tour magazine dated 9/2007 where on a wet curve............. the Schwalbe Ultremo was one of the better performing tyres.........has no tread and was described by the testers as "predictable" http://www.conti-tyres.co.uk/conticycle/road_tyres/attack%20force/Resistance%20Fighters.pdf.....

But this test like many others does not address the question at hand; if you took a few of the same tyres (same rubber, same carcass, same everything) and compared them in the wet with/without a file tread on them, that would better answer the question.

JH has basically done that; closer than anyone else has, anyway, and he believes that he gets more wet grip with the tread there. I think I get more confidence under similar conditions.

cheers

[tim-b]

Hi

In the link above (http://www.schwalbe.com/gb/profil.html) Schwalbe say that on normal, smooth, wet roads a slick tyre will grip better than one with a tread, which implies a degree of testing. Granted, I can't tell you what testing they did but Schwalbe doubtless have tremendous resources at their disposal

If you believe that you have more confidence on a treaded tyre then you will probably corner better on one. You pay your money and you take your choice, which is as it should be

Regards
tim-b

[Brucey]

I am old enough to remember that JB (and others) tested slick vs treaded tyres years ago and came to the same conclusion.

The net result of that was that they produced the avocet slick tyres. I tried some. I rapidly came to the conclusion that whilst they might have been the best thing since sliced bread on the roads they tested them on, in good old Blighty they were very nearly lethal.

What I don't recall anyone saying in such tests is exactly what treads they tried and if that was the only difference in the tyre or not. Also if there was a grip difference, exactly what it was.

My experience tells me that if I use a file treaded tyre that has shoulder wear (eg a badly worn rear rotated onto the front) in the wet, it is just like a slick; it steps out unpredictably. Now in fairness I have not deliberately shaved a tyre down to achieve this result; the tyres I have experienced this with have worn to that state; this means that they are older and maybe the rubber is a bit harder too. Possibly this is at least as important an effect in determining absolute grip. But on the other hand I've used file treaded tyres in hard compounds and they have been lacking in grip (or course) but have still behaved fairly predictably under most conditions.

Weirdly (even in this highly instrumented age) the final arbiter of tyre performance is still rider/driver feedback in practical testing. The way a tyre feels can't be measured easily, be it a car, motorbike or bicycle tyre. Not everyone feels the same things, both qualitatively and quantitatively. [Aside; I drove a friend's car recently; the same model as mine. Within a mile I'd identified three things that were set differently (wrongly) in the steering system; he hadn't noticed, despite having driven more different cars of this type, further, than I ever have.]

I guess if you are wearing leathers or are otherwise protected, and you have enough goes at it, you can get a feel for any tyre on any surface breaking away. But in the real world you get one go at it as you tip into a greasy off-camber turn; it isn't the same thing at all. I very much prefer a tyre that talks to me a bit before it quits gripping, and so far those tyres I've liked have had some tread on them rather than none, and when that tread is gone they have been horrible.

cheers

[tim-b]

Hi

Brucey said

I guess if you are wearing leathers or are otherwise protected, and you have enough goes at it, you can get a feel for any tyre on any surface breaking away.

...which is what the images on the Tour magazine article show, so it's a good test?? And pain-free for you and I

The final arbiter is you. I said

If you believe that you have more confidence on a treaded tyre then you will probably corner better on one. You pay your money and you take your choice, which is as it should be

Regards
tim-b

[Brucey]

...which is what the images on the Tour magazine article show, so it's a good test?? And pain-free for you and I ...

I read that test ages ago so I remember what they did more or less. Pain free, sure. But a good test? Kind of:

The test I'd be interested in would be what happened the first time they tipped into the turn, with something (anything) to lose if they either fell off or didn't go fast enough. I think that is perhaps a different test...

cheers

[reohn2]

Years ago I thought tread mattered particularly on chip n sealed tarmac in the sense that JH mentioned,ie;two pieces of sand/abrasive paper facing each other provide amazing grip if you try the slide them tangentially,whereas on the smooth/back side they slip easily.
I then on recommendation tried slick tyres and found them to be just as good,I was very wary of them in the wet initially,but I always was with treaded tyres too FTM.
I currently ride five types of tyres all slicks 700c,32mm Gatorskins on one tandem 32mm fr and 35mm rear on the another(I'd love to ride bigger section tyres but clearances won't allow it),and 559x40mm Vittoria Randonneurs on the childback.
Solo's,two bikes on 700cx35mm Vitt Hypers and one on 700x35mm Schwalbe Marathon Slicks(now discontinued).
This is purely anecdotal but I have complete confidence in all of them,all have some semblance of a tread pattern,but to the thumb nail feel like different kinds of ''rubber'',the Vittorias feeling more like what I'd term as ''rubbery'' in a softish grippy kind of way.
The Schwalbes have a two type tread ie; harder in the centre and soft on the shoulder,but don't feel any different to the thumb nail across the tread and feel more 'plasticy' than the Vitts as do Gators.
The only time I've ''lost it'' totally has been on green mossy lichen in the middle of a little used lane,and on a spot island in the piddling down rain.
I was being cautious on both occasions .
On tarmac I've had the correctable occasional step out on the rear but not on the front once the front goes it's gone IME.
Step outs and traction loss off road on the same tyres don't count as I'm on loose ground,but are surprisingly few and far between,and I find letting the bike move around a bit under me to be the best technique on such tracks and paths.
I feel totally confident on these tyres up to 18 to 20mph on gravel forest roads with any step outs being totally predictable and have descended at 45mph+ on rough chip n seal tarmac that I wouldn't trust any 28mm tyre over about 35mph
Which brings me to my next point.
I've raved about Vittoria Hypers long enough(yawn) and I love 'em,however PH of this parish, mentioned that he found them ''frightening'' in the wet,something I've not experienced.
But it could be that one persons riding technique is more cautious than another's,release agent left on the tyre after manufacture has been mentioned as a possible explanation for PH's bad experience,but that possibility aside we're back to personal experience and I've no reason to doubt PH's word or experience.
I've also heard and read of bad experiences with Gatorskins in wet conditions but am puzzled as I've nothing bad to say about them other than they're a bit of a harsh ride compared with other similar tyres.
Another tyre I've ridden quite a bit and have complete confidence it are Schalbe Kojaks,totally slick hence the name,and really sticky wet or dry.
I don't push any envelopes in the wet though,whatever the tyre.
One thing not mentioned so far is tyre pressures,IMO if you want to play skating in the wet on a bike, over inflated tyres are a good way to learn and there was a time when I rode 25mm tyres that I'd let a bit of air out of the tyres in wet conditions

[[XAP]Bob]

Aquaplaning isn't an issue - but there is still reduced grip in the wet.

I *think* that Brucey is saying that since a tyre with tread can squirm it is more compliant and therefore he has warning before it lets go.

So as with the CF/Steel comparison the manner in which the grip fails is at least as important as the grip level available.

[Brucey]

I think it is fair to say that some roads are a lot slippier than others, often in different ways. If you live in a rural part of the country where it rains lots, you may have a different grip expectation on local wet tarmac to someone who rides on worn urban tarmac with less rainfall.

cheers

[reohn2]

I think it is fair to say that some roads are a lot slippier than others, often in different ways. If you live in a rural part of the country where it rains lots, you may have a different grip expectation on local wet tarmac to someone who rides on worn urban tarmac with less rainfall.

cheers

Yet another part of the equation.Let's see,we have:-
Different riders,of varying daring and abilities
Different tarmacs, tyre rubbers/compounds,road and tyre temperatures,tyre pressures,etc,etc.
And the unknown contaminations ie;diesel oil,melting tar,moo/horse/sheep pooh .
Not to mention something I hadn't come across until the last couple of weeks in the Loire region,grape juice squeezing out of trailers full of the harvest and in the forest areas roads covered with acorns and sometimes Walnuts! It's hard work this holidaying