On the subject of tyres

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gorilla monsoon
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On the subject of tyres

Postby gorilla monsoon » Thu Feb 01, 2018 10:41 am

Over the last 50 years I have gained much knowledge and understanding of car road and race tyres and some knowledge and understanding of motorcycle road and race tyres.
I understand that race and rally car tyres use different rubber compounds and (for rally cars) tread patterns which maximise grip and handling qualities. same with racing motorcycles.
But do competition bicycles, as used for the Tour events for example, use different compounds to maximise handling or is it mostly gained through tread patterns and tyre pressures? Or doesn't it matter that much?
I have to admit that this generally boring subject about tyre compounds (tyres in general, really) fascinates me.
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Derny Driver
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Re: On the subject of tyres

Postby Derny Driver » Thu Feb 01, 2018 10:54 am

Tread on a bicycle tyre does nothing

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Re: On the subject of tyres

Postby Philistine » Thu Feb 01, 2018 11:09 am

Derny Driver wrote:Tread on a bicycle tyre does nothing


I read an article on this subject a couple of years ago. Sadly, I cannot remember the source, or even much of the detail. What I can remember is that it described the mechanism by which bald car tyres can aquaplane in the wet, and why that mechanism is not in play with bicycle tyres because of the higher pressures, narrower footprint, etc. Perhaps someone with a better memory can recall the article and link to it?

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Re: On the subject of tyres

Postby bychosis » Thu Feb 01, 2018 11:17 am

Derny Driver wrote:Tread on a **road** bicycle tyre does nothing

FTFY. Mountain bike tyres are a whole different realm. Different tread for loose gravel, hardpack, mud etc.
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Re: On the subject of tyres

Postby Thoglette » Thu Feb 01, 2018 11:35 am

Plenty of brands claiming wundermaterials (Conti's Chilli for example).

Carcass construction seems to be more important to winning (road & track races) than the ultimate level of grip.
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Re: On the subject of tyres

Postby Philistine » Thu Feb 01, 2018 1:38 pm

Philistine wrote:Perhaps someone with a better memory can recall the article and link to it?


OK I've found it.

https://www.sheldonbrown.com/tires.html

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Re: On the subject of tyres

Postby gorilla monsoon » Thu Feb 01, 2018 2:14 pm

Mr Brown didn't actually address the question I asked about tyre compounds but I will take it from the answers given so far that varying rubber compounds do not play a big part in bicycle racing.
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Re: On the subject of tyres

Postby mikesbytes » Thu Feb 01, 2018 3:11 pm

Bicycle's don't aquaplane so there is no need for rain grooves and rain grooves absorb energy.

The main thing to look for in a road or velodrome racing bicycle tyre is low rolling resistance.

The racing tyres used in events such as TDF are mainly singles, which fundamentally consist of a tyre stitched around a latex inner tube and is glued to the rim. They usually have little or no puncture protection. They are also preferred by some due to the ability to ride on a flat until the mechanic can give you a new wheel, I've never tested this out as I'm paying for the wheels :)

Most of us are using clinchers and the biggest improvement you can make is to change the inner tube to a latex tube. Tubeless clinchers of course get around the resistance of the tube by not having one but there's other factors.

Fatter tyres allow you to lower the air pressure and also by the nature of the contact patch provide lower rolling resistance. Thinner tyres provide better aerodynamics

BTW in simplistic terms rolling resistance is the ability of the tyre to fold over the micro bumps and for the sidewall to flex
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Re: On the subject of tyres

Postby Derny Driver » Thu Feb 01, 2018 3:36 pm

gorilla monsoon wrote:Mr Brown didn't actually address the question I asked about tyre compounds but I will take it from the answers given so far that varying rubber compounds do not play a big part in bicycle racing.

Most professionals simply ride the tyres that they get for free from their sponsors. Just like Formula 1 teams use their sponsors product, Bridgestone, Dunlop or whatever, cycling teams use whatever they are given. And the differences between manufacturers are so small that no-one bothers about what they are riding. There was an interesting example last year where a journalist tried to do a survey of tyre pressure by asking the Pro riders how many psi was in their tyres before the start of a race. Most had no idea and said to ask the mechanic. I have a feeling that some Pro riders may not even know what brand of tyre they use. Unlike car racing, tyres play a much smaller role in bike racing.
That said, most teams will ask their sponsor to supply their best race tyres to the team. That means they are light and have a soft compound. Its the construction of the sidewall of the tyre that is more important than what the rubber surface is that is bonded to it. Most riders use tubulars because they are lighter and less prone to punctures. Tubular rims are also lighter than clincher rims. Since they get their tubulars for free, can throw them away if they get a puncture, and have a mechanic who glues them on, that eliminates the 3 annoying downsides of tubular tyres.
Different races on different road surfaces may call for different tyres. Racing on rough roads may require a hard compound tyre like a Continental Competition. They are on the heavier side of the tyre spectrum but are very reliable. On a fast smooth surface where punctures are less likely then a much lighter tyre may be selected, with a thin flexible sidewall and a thin grippy rubber rolling surface. Like an expensive Veloflex or Challenge. For a perfectly smooth velodrome them super thin light tyres like Vittoria Pistas are used and pumped up to 160+ psi.
I have heard that for Paris-Roubaix, one of the roughest races on the calendar, many teams are experimenting with very wide tyres ...from the normal 25mm they are looking at maybe 32mm or bigger. Trying to elimate pinch flats and soften the jarring from the cobblestones.

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Re: On the subject of tyres

Postby Philistine » Thu Feb 01, 2018 5:16 pm

Derny Driver wrote:I have heard that for Paris-Roubaix, one of the roughest races on the calendar, many teams are experimenting with very wide tyres ...from the normal 25mm they are looking at maybe 32mm or bigger. Trying to elimate pinch flats and soften the jarring from the cobblestones.


Excellent and informative post DD. As someone who gets a ridiculous number of pinch flats, I find it strangely consoling that even the pro riders have trouble.

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Re: On the subject of tyres

Postby Kronos » Thu Feb 01, 2018 11:52 pm

There really isn't a wonder compound on bicycle tyres. Although these days the market is widening with different types of compounds and treds it doesn't really mean a lot. Put it this way, if I can run two different compounds and tred patterns on my road bike as I have done in a past life its the definition of tred really not doing anything at all. Bigger tyres and wider rims will go some way to making your ride more smooth, the latest advances gets you to tyres you can put 40psi in just like your mountain bike or road tyres which will automatically reduce the significant harshness of road bike tyres and road chatter, but aside from that point there really is no benefit in different tyre tred for road bikes. In a professional sense as per above the general thing for cycling is to ask for a lighter tyre/inner tube to reduce the weight of the bike until which point you get to the pointy end of a competition where you can afford tubular tyres/rims.

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Re: On the subject of tyres

Postby Derny Driver » Fri Feb 02, 2018 12:25 am

Kronos wrote: In a professional sense as per above the general thing for cycling is to ask for a lighter tyre/inner tube to reduce the weight of the bike until which point you get to the pointy end of a competition where you can afford tubular tyres/rims.

Light tyres have always been thought to roll better ie they are faster. Nothing to do with reducing overall bike weight.
My uncle was a pro track rider in the 40's 50s early 60s ... I have a letter he wrote to my dad in 1949 or 1950 saying how his manager was going to drive from Gent Belgium to Paris to pick up a pair of silk tyres which my uncle was to use in the world pursuit titles. Steel bikes in those days were all a standard weight. Wheels were pretty much all the same too, 36 tied and soldered spokes. Maybe "special"
32 spoke wheels for a pursuit.
So the silk tyres were valued for their perceived speed. All tyres were tubular. There was no such thing as a weight weeny until later years where riders started drilling holes in seatposts, handlebars and chainrings (maybe 70s?).
A light tyre with a thin flexible casing and a latex tube has the added advantage of having a lighter rotational mass. Im no scientist but I think removing weight from rotating things like tyres and cranks and pedals is more beneficial than removing weight off the frame or seatpost or something that doesnt move.

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Re: On the subject of tyres

Postby Kronos » Fri Feb 02, 2018 12:48 am

Thanks for the clarity.

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Re: On the subject of tyres

Postby MattyK » Fri Feb 02, 2018 9:19 am

Derny Driver wrote:Just like Formula 1 teams use their sponsors product, Bridgestone, Dunlop or whatever, cycling teams use whatever they are given. And the differences between manufacturers are so small that no-one bothers about what they are riding.

It's been a while hasn't it? :lol: F1 has been on Pirelli control tyres for several years now...

In terms of compound, I think there are at least some tyres out there that use a harder central strip for wear and rolling resistance, and softer sides for more cornering grip, but I couldn't name them.

One of the more interesting variations seems to be in aerodynamics. Continental GP4KS2s seem to reliably test better than most others. I'm guessing it's something to do with their tread pattern and generating a turbulent boundary layer, but I don't think anyone has really dug into why.
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Re: On the subject of tyres

Postby Derny Driver » Fri Feb 02, 2018 9:30 am

MattyK wrote:It's been a while hasn't it? :lol: F1 has been on Pirelli control tyres for several years now...

:D
I don't watch it. Last F1 race I saw was when Ayrton Senna was racing. :?

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Re: On the subject of tyres

Postby g-boaf » Fri Feb 02, 2018 10:21 am

Derny Driver wrote:
MattyK wrote:It's been a while hasn't it? :lol: F1 has been on Pirelli control tyres for several years now...

:D
I don't watch it. Last F1 race I saw was when Ayrton Senna was racing. :?


The amazing self-destructing Pirelli control tyres. If the F1 tyres are so poor, then it doesn't give much hope for the bicycle tyres from Pirelli. :P

Speaking of senna, was watching this morning:

this could be the opportunity he's been looking for... and he's going through - OUT! Oh my goodness! This is fantastic!


Great racing up until then. The culmination of the war between the two drivers. Classic F1, not the same anymore. :(

Back to normal programming.

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Re: On the subject of tyres

Postby Jmuzz » Fri Feb 02, 2018 10:36 am

Yes there is as much going on with bike tyres as with motorsport tyres and they range from hard dry rubber to the modern stuff which you can leave fingernail prints in.

There are different compounds, different rubber flex, different weight. You will find various websites/blogs which run tests and rate rolling resistance and strength.

There are tradeoffs between puncture resistant tyres which are heavier and more firm vs lowest weight (it can be significant, when in the realm of big $ for 6kg premium bikes).

A current development in the market is the move away from super skinny tyres. Tyres were getting skinnier and harder, but now people are claiming that wider and softer can have the same performance in many situations while being more comfortable, safer grip and less punctures.

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Re: On the subject of tyres

Postby warthog1 » Fri Feb 02, 2018 5:34 pm

Derny Driver wrote:
MattyK wrote:It's been a while hasn't it? :lol: F1 has been on Pirelli control tyres for several years now...

:D
I don't watch it. Last F1 race I saw was when Ayrton Senna was racing. :?


Neither do I. Very boring and processional.
MotoGp, now that's racing.

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Re: On the subject of tyres

Postby Derny Driver » Fri Feb 02, 2018 6:00 pm

warthog1 wrote:
Derny Driver wrote:
MattyK wrote:It's been a while hasn't it? :lol: F1 has been on Pirelli control tyres for several years now...

:D
I don't watch it. Last F1 race I saw was when Ayrton Senna was racing. :?


Neither do I. Very boring and processional.
MotoGp, now that's racing.

Yep. Isle of Man is my favourite. I like the rallying too. Whatever happened to Group B? They were the real deal.

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Re: On the subject of tyres

Postby g-boaf » Fri Feb 02, 2018 6:18 pm

A crash is what happened to Group B, a very bad crash with Henri Toivonen and the savage Lancia Delta S4 and that was it.

Those cars were monsters - some of the most violent rally cars of all, and potentially an explosion of performance was about to erupt with the 5 cylinder 4wd Audi Group S prototype (a mid-engined machine) and the Lancia ECV with its brilliant "tri-flux" engine (http://www.speedhunters.com/2013/02/the-triflux/).
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Re: On the subject of tyres

Postby NASHIE » Fri Feb 02, 2018 6:20 pm

Derny Driver wrote:
warthog1 wrote:
Derny Driver wrote: :D
I don't watch it. Last F1 race I saw was when Ayrton Senna was racing. :?


Neither do I. Very boring and processional.
MotoGp, now that's racing.

Yep. Isle of Man is my favourite. I like the rallying too. Whatever happened to Group B? They were the real deal.


Check out some of the Irish rally championships on youtube. They have great rally regs over there that allow more freedom to build cars that get the fans through the gates. Mk2 escorts with all the modern go-gear, sequential gearbox etc. Probably $100-$200k cars to build but really give the sport that 80s thrill. Still some group Bs to been seen in some European series as well.
As much as i hate saying it....formula E is better viewing than F1. Its very close racing and having to pitstop to change cars (batterys run out) makes for a good race.

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Re: On the subject of tyres

Postby Duck! » Sat Feb 03, 2018 9:51 pm

NASHIE wrote:
Derny Driver wrote:
warthog1 wrote:
Neither do I. Very boring and processional.
MotoGp, now that's racing.

Yep. Isle of Man is my favourite. I like the rallying too. Whatever happened to Group B? They were the real deal.


Check out some of the Irish rally championships on youtube. They have great rally regs over there that allow more freedom to build cars that get the fans through the gates. Mk2 escorts with all the modern go-gear, sequential gearbox etc. Probably $100-$200k cars to build but really give the sport that 80s thrill. Still some group Bs to been seen in some European series as well.
As much as i hate saying it....formula E is better viewing than F1. Its very close racing and having to pitstop to change cars (batterys run out) makes for a good race.

And this is relevant to bike tyres how?

Kronos wrote:There really isn't a wonder compound on bicycle tyres. Although these days the market is widening with different types of compounds and treads it doesn't really mean a lot. Put it this way, if I can run two different compounds and tread patterns on my road bike as I have done in a past life its the definition of tread really not doing anything at all.

Maybe no "wonder compounds", but there absolutely are different compounds for different purposes, and they will greatly affect the handling of the bike. Soft, sticky compounds deliver tenacious cornering grip, even in the wet, but suffer in durability. At the other end of the spectrum, harder "training" or commuting compounds will last a long time, but the trade off is a marked reduction in cornering grip, which affects how confidently you can chuck the bike at corners and expect it to get you through, especially in the wet.
Philistine wrote:
Derny Driver wrote:Tread on a bicycle tyre does nothing


I read an article on this subject a couple of years ago. Sadly, I cannot remember the source, or even much of the detail. What I can remember is that it described the mechanism by which bald car tyres can aquaplane in the wet, and why that mechanism is not in play with bicycle tyres because of the higher pressures, narrower footprint, etc. Perhaps someone with a better memory can recall the article and link to it?

Car tyres can aquaplane because they have a wide, flat contact profile that can ride up over a layer of surface water. Tread enables the water to be ejected out fron under the tyres. Bike tyres have a rounded contact profile which cuts through surface water and pushes it aside, therefore do not need tread on road.
I had a thought, but it got run over as it crossed my mind.

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Re: On the subject of tyres

Postby Ross » Sun Feb 04, 2018 9:53 am


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Re: On the subject of tyres

Postby g-boaf » Sun Feb 04, 2018 9:40 pm

I tried these Specialized tyres, S-Works which are supposedly the fastest tyres of their type, in a 26mm size (not a typo).

Rolling performance, maybe a little bit better than a GP4000S II, but what I did notice was that they seemed to grip very well. If they are durable enough, they could be keepers. And they do fit on the 2013/2014 style Giant TCR Advanced SL frame no problem at all. Comfort, I didn't really notice any difference between a 25mm GP4000S II and these. Need more time with them to get a proper impression.

With any luck someone here will get the equivalent Pirelli P-Zero tyres and report on those.

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Re: On the subject of tyres

Postby Thoglette » Sun Feb 04, 2018 11:34 pm

Like Gorilla I spent many years playing with racing cars and motorbikes. And I'd like to underline that, while there are some OK and some truly awful tyre compounds for bike tyres, there's really nothing really sticky. (I used to use A032s on my daily driver)

The bottom line is that the suspension technology for bikes is just not there to utilise real grip and it is just not important for bike racing. There's not enough power available to make up for the loss of watts that a "proper" setup would cause.
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