(Race) Tyre thread!

[mike wilson]

In the Porky thread, Ratchet said (amongst many other things)

 

I'd also add that what tires work well on the track are NOT THE SAME as what works on the road. In fact, for all practical purposes, they are very much mutually exclusive tire requirements, chief of which is that a racing tire is typically designed for ONE HEAT CYCLE ONLY.

 

I can understand that a race tyre should be at its expiry point as the race ends, having given its all in the process. But I can find no evidence for the above.

 

In F1, for instance, tyres are often used more than once. Admittedly not used to their full potential at first but they are certainly heat cycled more than once.

 

Can anyone explain the chemistry involved?

[macguzzi]

Can anyone explain the chemistry involved?

Very rubbery

[Paul Minnaert]

race tyres have a limited temperature operating range. The don't have to have that. The ones realy racing with these tyres, do one race with them, because the nicest part is gone from the tyre. And if it does make a small difference, it could mean you win.

The more ambitious hobby racer wants new tyres, that means produced not long ago.

[GuzziMoto]

Some manufacturers make Qualifiers that are designed for one lap. But most race tires are good for about 6-8 heat cycles before the performance falls way off. However, the first heat cycle is usually( but not always) the best the tire has. Sometimes you will see teams putting a heat cycle on a tire in practice so they can use it in the race with one cycle already on it.

However none of this changes the fact that race tires do not make good street tires. I would rather race on street tires then ride on the street on race tires.

[dlaing]

Can anyone explain the chemistry involved?

I am just guessing but the rubber probably becomes tempered and hardened after it cools down from one heat cycle.

How big a deal is that, I don't know.

Simply braking in to a turn will raise the temperature of the front tire and blazing down the straight would cool and temper the rubber at the surface.

Oxygen exposure, especially at high temperatures, should also have a hardening effect on the rubber.

Street tires may have chemicals added to reduce oxidation of the rubber

Yep, all speculation. Feel free to ignore.

[Guest ratchethack]

In the Porky thread, Ratchet said (amongst many other things)

I'd also add that what tires work well on the track are NOT THE SAME as what works on the road. In fact, for all practical purposes, they are very much mutually exclusive tire requirements, chief of which is that a racing tire is typically designed for ONE HEAT CYCLE ONLY.

I can understand that a race tyre should be at its expiry point as the race ends, having given its all in the process. But I can find no evidence for the above.

 

In F1, for instance, tyres are often used more than once. Admittedly not used to their full potential at first but they are certainly heat cycled more than once.

 

Can anyone explain the chemistry involved?

Mike, I offer no explanation for the chemistry involved, but you may've missed this, cross-posted from another thread. :

 

Possibly worth a re-re-post here. . .

 

Street vs. Race

 

Choosing the right tire for the job

 

Street vs. Race

Choosing the right tire for the job

By Andrew Trevitt, SportRider Magazine

 

We know what you're thinking: Those namby-pamby street tires are for weenies, and the DOT race tires work way better on the street, right? Wrong. While you're struggling with a stone-cold Supersport toss-off that's rock hard from too many heat cycles, your buddies on their high-performance street tires will be long gone.

 

Race tires are specifically meant to do one thing: Stick like glue, for one heat cycle. To that end, they are designed with an entirely different philosophy from street tires, and those differences make them unsuitable for street use. One obvious difference is most race tires have fewer grooves for more grip. And while this is great on a dry road, riding in the rain can get pretty hairy. But this is just what you can see, and it's perhaps more important to know what's going on inside the tire to fully understand the differences.

 

Max Martin, with Avon Tyres, says its Azaro Supersport bun is designed with a high arch and very high crown, particularly the front tire. This makes a race bike steer quickly (at the expense of stability), and gives more surface area on the side of the tire for more traction at full lean. The Azaro Sport street tire has a rounded profile, which puts more tread on the road when the bike is straight up for better wear, as well as being more stable and allowing easier line changes in midcorner. Put the race tire on the street and it will wear quicker due to the pointy profile.

 

Martin also pointed out differences in casing design, with the Supersport tire having an additional ply and tighter winding for higher cornering loads. However, on larger bumps found on public roads, this extra rigidity will have the race tire chattering earlier than would the softer and more compliant street tire.

 

Sport Tire Services' Dennis Smith points out that the Dunlop D207 Sportmax is designed to work correctly at the reduced temperatures found on the street, as opposed to the higher temperatures found on the racetrack. And that you'd almost never be able to generate track temperatures during a street ride to take advantage of the extra grip offered from a race tire. Smith also mentioned the material and production costs are totally different for each type, with the race tires costing significantly more than the street tires.

 

According to Mike Manning of Dunlop Tires, the D207GPs utilize a "cut breaker construction," in which the plies are overlapped to give good side grip. Compare that with the D207 Sportmax, which has a "jointless belt construction," giving more stability and a smoother ride. Manning also added that a street tire's rubber compound is designed to go through more heat cycles, as well as having silica added to give better wet grip.

 

[Trevitt's bottom line:]

 

So let's see, a street tire will generally have better wear, more stability and superior wet-weather performance compared with a race tire, offer similar grip (and most likely more) at real-world tire temperatures, and give constant performance over many heat cycles-all for less money. Sign us up.

[FuelCooler]

I can understand that a race tyre should be at its expiry point as the race ends, having given its all in the process. But I can find no evidence for the above.

 

In F1, for instance, tyres are often used more than once. Admittedly not used to their full potential at first but they are certainly heat cycled more than once.

 

Can anyone explain the chemistry involved?

 

Mike, I offer no explanation for the chemistry involved, but you may've missed this, cross-posted from another thread. :

 

Possibly worth a re-re-post here. . .

 

Street vs. Race

 

Choosing the right tire for the job

 

Street vs. Race

Choosing the right tire for the job

By Andrew Trevitt, SportRider Magazine

 

We know what you're thinking: Those namby-pamby street tires are for weenies, and the DOT race tires work way better on the street, right? Wrong. While you're struggling with a stone-cold Supersport toss-off that's rock hard from too many heat cycles, your buddies on their high-performance street tires will be long gone.

 

Race tires are specifically meant to do one thing: Stick like glue, for one heat cycle. To that end, they are designed with an entirely different philosophy from street tires, and those differences make them unsuitable for street use. One obvious difference is most race tires have fewer grooves for more grip. And while this is great on a dry road, riding in the rain can get pretty hairy. But this is just what you can see, and it's perhaps more important to know what's going on inside the tire to fully understand the differences.

 

Max Martin, with Avon Tyres, says its Azaro Supersport bun is designed with a high arch and very high crown, particularly the front tire. This makes a race bike steer quickly (at the expense of stability), and gives more surface area on the side of the tire for more traction at full lean. The Azaro Sport street tire has a rounded profile, which puts more tread on the road when the bike is straight up for better wear, as well as being more stable and allowing easier line changes in midcorner. Put the race tire on the street and it will wear quicker due to the pointy profile.

 

Martin also pointed out differences in casing design, with the Supersport tire having an additional ply and tighter winding for higher cornering loads. However, on larger bumps found on public roads, this extra rigidity will have the race tire chattering earlier than would the softer and more compliant street tire.

 

Sport Tire Services' Dennis Smith points out that the Dunlop D207 Sportmax is designed to work correctly at the reduced temperatures found on the street, as opposed to the higher temperatures found on the racetrack. And that you'd almost never be able to generate track temperatures during a street ride to take advantage of the extra grip offered from a race tire. Smith also mentioned the material and production costs are totally different for each type, with the race tires costing significantly more than the street tires.

 

According to Mike Manning of Dunlop Tires, the D207GPs utilize a "cut breaker construction," in which the plies are overlapped to give good side grip. Compare that with the D207 Sportmax, which has a "jointless belt construction," giving more stability and a smoother ride. Manning also added that a street tire's rubber compound is designed to go through more heat cycles, as well as having silica added to give better wet grip.

 

[Trevitt's bottom line:]

 

So let's see, a street tire will generally have better wear, more stability and superior wet-weather performance compared with a race tire, offer similar grip (and most likely more) at real-world tire temperatures, and give constant performance over many heat cycles-all for less money. Sign us up.

 

Everytime I read one of these tire posts by Ratchet I feel I need to point something out that I believe Ratchethack hasn't had the time or need to get into, so I will, just to clear up some confusion:

The Dunlop D207, D208 and Qualifier, the Michelin Pilot Sports, the Metzler M1s and Pirelli Corsas (not Supercorsas) are not DOT race tires or Sport Touring tires. They are sportbike tires that are absolutely fine for the street. They may wear out faster, but they still are streetbike tires.

Cheers,

Steve

[Guest ratchethack]

Everytime I read one of these tire posts by Ratchet I feel I need to point something out that I believe Ratchethack hasn't had the time or need to get into, so I will, just to clear up some confusion:

The Dunlop D207, D208 and Qualifier, the Michelin Pilot Sports, the Metzler M1s and Pirelli Corsas (not Supercorsas) are not DOT race tires or Sport Touring tires. They are sportbike tires that are absolutely fine for the street. They may wear out faster, but they still are streetbike tires.

Cheers,

Steve

Steve, you can trust with 100% confidence that I've carefully read every outside source that I post on this Forum, and every article and source that I link here.

 

I'm afraid that I'm confused by your post, and don't understand your point. I thought the article I posted was quite straightforward. The entire thrust of the article is to make the distinction that you seem to think needs clarification here, so I can't quite comprehend how you've decided that this needs further clarification. The article above makes the distiction, the topic of the thread is race tires, there are specific comments in the article about race tires that contrast their design and function with street tires, as well as the differing requirements relative to heat cycles, per the discussion.

[FuelCooler]

Steve, you can trust with 100% confidence that I've carefully read every outside source that I post on this Forum, and every article and source that I link here.

 

I'm afraid that I'm confused by your post, and don't understand your point. I thought the article I posted was quite straightforward. It appears that you believe I've failed to make a distinction between the tires you listed and racing tires, but I can't comprehend how you've arrived at this conclusion, since the article above makes the distiction, the topic of the thread is race tires, there are specific comments in the article about race tires that contrast their design with street tiresas well as mention of the differing requirements relative to heat cycles, per the discussion.

 

Sorry Ratchet

Perhaps I should have reposted your Sport touring Wet /Dry quotes (as well) from that German magazine tire comparison test. I didn't want a huge post. My point is: From reading your posts on tires in general, it seems that some on this forum might think that alot of tires other than the following Sport Touring type tires - Metzeler Z6s, Pirelli Stadas, Michelin Pilot Roads, are for racers or track day bikes, and therefore unnecessary on our V11s. I am not saying you have ever said those things on this forum, but I sense some may suspect you are implying that (well at least one,...me).

I completely agree that DOT race rubber will perform poorly on the street. But just because a tire may be advertised as super-sticky and in use is fast wearing, that doesn't make it race rubber or that it should be regarded as poison on a V11. Again, not that you said that.

I used to race on Michelin Hi-Sports (as did many others) when they only came in one compound (very early 1990's). They were also my street tires. They were fine street tires. Toward the end of the 1993 season, Michelin started selling different compounds for their Hi-Sport tire (A or B, IIRC). This was about the time that Dunlop started selling there 364 (?) Rear Sportmax. I never tried either, but I believe those were 'Race Only DOT' tires and not fit for the street.

If I have lost my mind in thinking that someone (other than myself) might assume they should beware of 'sport' tires on their Guzzi because of your comments, please forgive me.

FWIW- I have tried ME4's, M3 Race (STD on TL1000), Pilot Roads, Pilot Sports, Sportmax'es D205, D207 and D208, Original Battleaxe's that came on the 1993 CBR900RR, K591's (and K591 Race) and Pirelli Dragons. The only ones that spooked me a bit were the ME4's and the 3 year old used K591 Races a buddy gave me. Hell, I did a track day on the 204s in 1991 (GSXR750) and on the 208's in 2000 (F4 Honda). Sticky enough to out run my buddies on Michelin Sports!

Cheers,

Steve

Edit-Yes, the above Sport Rider article clearly stated D207 as a street tire. But the New Sticky Qualifiers are street tires as well, regardless of the name.

 

Ratchet sincerely I apologize for my Paranoia I searched and I found- 10-27-07 Ratchet quote

"I wear my tires all the way to the edges, and I select tires for mountain road riding that tends to be far more challenging and demanding in every respect than I reckon most riders experience on a regular basis, myself included. Having ridden on many Sport tires on the Guzzi, I prefer Sport/Touring tires for their far superior mileage, whilst giving away little to Sport tires in terms of handling and grip -- and in at least two cases, giving away NOTHING in terms of handling, quite the opposite"

Again sorry! I failed to read this post!

[Guest ratchethack]

Sorry Ratchet

No problemo, mi compadre!

[mike wilson]

Mike, I offer no explanation for the chemistry involved, but you may've missed this, cross-posted from another thread. :

 

It's that article that triggered the question because nowhere in there does it explain why a race tyre will only tolerate one heat cycle. Plenty of explanation of the other factors involved but not the heat cycle thing. My curiosity has been piqued. I smell an urban legend....

[mike wilson]

So I google "heat cycle" with "tyre" and "race" and one of the first things to come up is this thread...

 

Then:

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=66

 

A race tyre heat cycling system. Quote "Avon, Hoosier, Kumho and Yokohama all recommend that their competition tires be "heat cycled" before being run in competition."

 

More advice from Avon:

http://www.avonracing.com/tech/advice.htm

 

A few other interesting sites in the list but nothing to really get your teeth into. Although it's _possible_ that race tyre chemistry is so dramatically different from the road version that it can only tolerate a much more limited number of heat cycles, it seems , to me, that the real reason for retiring a race tyre after very limited use is that it is completely shagged out from other causes.

[emry]

Most race teams will do what is called "scrubing in" to check for balance and vibration issues, normally this is only one lap. This also should generate enough heat to allow the tire compounds to settle. It is fairly well accepted that a race tires first full heat cycle is its best. As more heat cycles are put though a tire or a prolonged heat cycle (such as a race) the tire becomes greasy and begins to loose grip. You will hear riders talk about how their tire "went off" toward the end of the race.

 

As for the chemistry don't forget that tires are vulcanized rubber. Heat is used to cure the rubber.

 

Tire rack heat cycling

 

As for the true chemisty - Fire an email to Jim Allen

[mike wilson]

As for the chemistry don't forget that tires are vulcanized rubber. Heat is used to cure the rubber.

 

Tire rack heat cycling

 

Tyres are hotter coming out of the mould than they ever will be in normal use. If there was going to be terminal degradation from heat alone it would happen then. Your link is the same as my first one. Who is Jim Allen?

[emry]

Heat is used during the vulcanization process to turn a very soft plyable rubber into a very durable and resiliant one by actually changing the chemical compounds in the rubber. This is done in a mold under very high pressure. Granted the heat used is higher, this is what is required to cause the chemical changes. After the vulcanization the tire is quite chemically different than it began, heat now acts difeerently on the newly formed molecules. And the forces acting on a tire on a motorcycle is very different than sitting in a static mold.

 

Vulcaniztion

 

Sorry to swipe your link, it appears we were researching at the same time. Kudos.

 

Jim Allen is the US manager of Roadracing for Dunlop. That was a tongue in check suggestion. <_>