[Keith Code]

The Bands of Traction

If you saw the last GP in Portugal this past weekend you couldn’t help but be impressed with the traction capabilities of the tires. The corner speeds, lean angles and how quickly the riders could flick the bikes is astounding. Clearly, that level of riding can only be achieved by those who are able to trust the tires. How do you arrive at the point of being able to use current tire technology?

The Edge

Anyone would like to be able to read and sense traction at a pro level. That would mean something like: to always know when you were at the edge of traction and feel comfortable enough to bring it there when and if you wished to.

For a professional rider that “edge” has to be pretty wide. Think of it this way: you must be able to ride in that band of traction or you don’t get paid. That is a different perspective than most sportbike enthusiasts have on the subject of traction.

Bands of Traction

Feeling in control of tire grip would mean reading the signs of losing grip and knowing what those signs meant. If there was a nice long, tapering curve to losing traction, where the signs of it ramped up very gradually from a squirm to a little slip and then to a slip & grip and then on to a nice, clean, power-on slide we’d all be traction masters. The fact is, tires do have signs and signals just like that but talking about it doesn’t make it any more real or comfortable without some personal experience to back it up.

Reading the Signs

By questioning a track day or club race rider you could pretty well figure out what lap times they’d be able to turn by what traction signals they had experienced and were comfortable with. You would find most riders stuck right at the “squirm” band of traction.

Not too bad really, providing that the rider’s basic riding techniques were firm, he could go quite quick at the squirm band of riding. This would typically give lap times that were within 8 to 12 seconds of AMA Pro 600 Supersport times. The squirm band starts right when the rider has enough pressure on the tires to get a decent sized footprint on the pavement, which is the technological magic of radial tire design.

Many riders think there is less rubber on the ground when the bike is leaned over but it is the opposite, there is more. They think that because they can’t add gobs of throttle when it is leaned over. In actual fact, as we bring the bike up we can add more throttle because the tires do not have to deal with the leaned over side-loading from the cornering. When the bike is straight up it has the least rubber on the ground but no side loading to take away from the available traction.

Technical Skills

Having good technical skills is the only sane route to mastering the bands of traction and reading their signs. In other words, without a firm grounding in basics, it’s easy for riders to misidentify what they think is a loss of traction when it isn’t or because of poor technique they may skip a band or two and get themselves into trouble.

Sloppy throttle control gives a false sense of tire grip. Using lean angle in the wrong part of the turn for the wrong reasons gives a distorted feel for it. How the rider sits on the bike can have a huge effect on it. Confusing inputs into the handlebars is another classic way of misreading the signs your tires can give you. All of them will set you up to miss the signals completely.

These, and others, are all technical aspects of riding that can be adjusted by the rider without having to touch the bike’s suspension. Being coached through these points is the way to go and leads to control of the mysterious traction questions riders have.

Tire Technology

Riders know that 21st century motorcycles and tires are better than they are. Fine. What security does anyone have that this is true beside the thin hope that if they do get into trouble the bike and tires will save their bacon?

One aspect is tire warmers and the security they seem to give riders. Tire warmers are a fact of life these days even at track day events. What many riders fail to realize is that by the time they get around a lap or two the tires can actually cool down.

Tire temperature is based on tire usage. The higher loads the hotter they get. If you aren’t in the band of traction that will take you over the tire warmer temp you really are looking at a security blanket that isn’t totally real. For sure it can save a rider from the embarrassment of a first lap, cold tire crash and that is the good news.

New Skins

Aside from crashing, tires are the single most expensive, consumable cost riders have for track days and racing. Tires do wear out and that wear is part of the key to their ability to grip.

Take the tire’s viewpoint for a moment. They are willing to stick provided there is rubber covering the cords; the temperature is up to the loads being demanded by the rider’s speed; lean angle; braking and drive off the corners. Tires wear out just like skin. As the outer layer becomes dry it is swept away by friction. On your clothes when it comes to skin. On the pavement when it comes to tires.

Tires, like skin, dry out from age or from heat. Exposing the next layer of fresh, pliable rubber underneath to the road is critical to performance. If the dry rubber remains on top, traction isn’t as good. To expose the new, fresh rubber, enough load must be put on the tires to “clean” them. It has been theorized that 10% tire slippage is the ideal situation for tires because it keeps the temperature up and at the same time “cleans” them.

Heat Cycles

How many heat cycles a tire has gone through, theoretically, has a huge effect on how well they work. The heating and cooling is supposed to reduce their grip by changing the chemistry that holds the rubber together and riders sometimes worry about it.

The Dunlops on our school coach’s bikes are usually take-offs; they’ve already been raced on and often raced on by pro riders who can get them up to full temperature. We then use them for days of track riding and all the coaches can go quick enough to run club race lap times and most of them could qualify for an AMA Supersport race. While our coaches don’t ride hot laps every moment of every day the tires do get a minimum of 30 heat cycles a day.

Here’s the point: The record for a front tire is 38 school days. The record for a rear is 18 days. The average laps per day would be around 90. I think Dunlop knows something about tires and taking up the devils advocate, these are the stickiest, most expensive ones so perhaps, at least for the quicker riders, there is economy in buying the good stuff after all.

NOTE: We change the Dunlops on our ’07 ZX6 student bikes every three or four days.

The Sticky Stuff

Everyone wants to have the stickiest rubber they can afford but it isn’t sticky until they can put the big load on the tires. Most riders would do better and learn heaps more about traction with something lesser than full race, factory rider developed tires. Why? They don’t have to put the big loads on the tires to start to experience the bands of traction as listed above.

Look at it this way. If you are using the tire at the bottom end of where it was developed by pro riders would it actually save you if you got brave for a moment? The answer is no. Pushing the loads on the tires up for a moment when the rest of the lap was at your normal pace will not give the tire enough time to warm up to the level you momentarily demand from it to handle the situation.

In other words, your potential and that of the tires have to come up together for you to take advantage of what the tire has to offer. To a large degree, the security of the stickiest rubber is false. Until you arrive at some consistency in your levels of speed and lean angle and throttle control and the other technical parts of riding it is no more then blind faith.

Trusting the Tires

In the end it isn’t about the tires it is about the rider. It’s about using good technique and having good technical skills. It’s about gaining some consistency with them and knowing you can do it. After that, it’s not so difficult to trust your tires because you trust yourself.


Keith Code

ⓒ 2007, all rights reserved. No part of this article may be reproduced by any means without express written permission of the author.

[dogslowboy]

[quote name='Keith Code' date='Sep 19 2007, 08:17 PM' post='4823']
The Bands of Traction

If you saw the last GP in Portugal this past weekend you couldn’t help but be impressed with the traction capabilities of the tires. The corner speeds, lean angles and how quickly the riders could flick the bikes is astounding. Clearly, that level of riding can only be achieved by those who are able to trust the tires. How do you arrive at the point of being able to use current tire technology?

The Edge

Anyone would like to be able to read and sense traction at a pro level. That would mean something like: to always know when you were at the edge of traction and feel comfortable enough to bring it there when and if you wished to.

For a professional rider that “edge” has to be pretty wide. Think of it this way: you must be able to ride in that band of traction or you don’t get paid. That is a different perspective than most sportbike enthusiasts have on the subject of traction.

Bands of Traction

Feeling in control of tire grip would mean reading the signs of losing grip and knowing what those signs meant. If there was a nice long, tapering curve to losing traction, where the signs of it ramped up very gradually from a squirm to a little slip and then to a slip & grip and then on to a nice, clean, power-on slide we’d all be traction masters. The fact is, tires do have signs and signals just like that but talking about it doesn’t make it any more real or comfortable without some personal experience to back it up.

Reading the Signs

By questioning a track day or club race rider you could pretty well figure out what lap times they’d be able to turn by what traction signals they had experienced and were comfortable with. You would find most riders stuck right at the “squirm” band of traction.

Not too bad really, providing that the rider’s basic riding techniques were firm, he could go quite quick at the squirm band of riding. This would typically give lap times that were within 8 to 12 seconds of AMA Pro 600 Supersport times. The squirm band starts right when the rider has enough pressure on the tires to get a decent sized footprint on the pavement, which is the technological magic of radial tire design.

Many riders think there is less rubber on the ground when the bike is leaned over but it is the opposite, there is more. They think that because they can’t add gobs of throttle when it is leaned over. In actual fact, as we bring the bike up we can add more throttle because the tires do not have to deal with the leaned over side-loading from the cornering. When the bike is straight up it has the least rubber on the ground but no side loading to take away from the available traction.

Technical Skills

Having good technical skills is the only sane route to mastering the bands of traction and reading their signs. In other words, without a firm grounding in basics, it’s easy for riders to misidentify what they think is a loss of traction when it isn’t or because of poor technique they may skip a band or two and get themselves into trouble.

Sloppy throttle control gives a false sense of tire grip. Using lean angle in the wrong part of the turn for the wrong reasons gives a distorted feel for it. How the rider sits on the bike can have a huge effect on it. Confusing inputs into the handlebars is another classic way of misreading the signs your tires can give you. All of them will set you up to miss the signals completely.

These, and others, are all technical aspects of riding that can be adjusted by the rider without having to touch the bike’s suspension. Being coached through these points is the way to go and leads to control of the mysterious traction questions riders have.

Tire Technology

Riders know that 21st century motorcycles and tires are better than they are. Fine. What security does anyone have that this is true beside the thin hope that if they do get into trouble the bike and tires will save their bacon?

One aspect is tire warmers and the security they seem to give riders. Tire warmers are a fact of life these days even at track day events. What many riders fail to realize is that by the time they get around a lap or two the tires can actually cool down.

Tire temperature is based on tire usage. The higher loads the hotter they get. If you aren’t in the band of traction that will take you over the tire warmer temp you really are looking at a security blanket that isn’t totally real. For sure it can save a rider from the embarrassment of a first lap, cold tire crash and that is the good news.

New Skins

Aside from crashing, tires are the single most expensive, consumable cost riders have for track days and racing. Tires do wear out and that wear is part of the key to their ability to grip.

Take the tire’s viewpoint for a moment. They are willing to stick provided there is rubber covering the cords; the temperature is up to the loads being demanded by the rider’s speed; lean angle; braking and drive off the corners. Tires wear out just like skin. As the outer layer becomes dry it is swept away by friction. On your clothes when it comes to skin. On the pavement when it comes to tires.

Tires, like skin, dry out from age or from heat. Exposing the next layer of fresh, pliable rubber underneath to the road is critical to performance. If the dry rubber remains on top, traction isn’t as good. To expose the new, fresh rubber, enough load must be put on the tires to “clean” them. It has been theorized that 10% tire slippage is the ideal situation for tires because it keeps the temperature up and at the same time “cleans” them.

Heat Cycles

How many heat cycles a tire has gone through, theoretically, has a huge effect on how well they work. The heating and cooling is supposed to reduce their grip by changing the chemistry that holds the rubber together and riders sometimes worry about it.

The Dunlops on our school coach’s bikes are usually take-offs; they’ve already been raced on and often raced on by pro riders who can get them up to full temperature. We then use them for days of track riding and all the coaches can go quick enough to run club race lap times and most of them could qualify for an AMA Supersport race. While our coaches don’t ride hot laps every moment of every day the tires do get a minimum of 30 heat cycles a day.

Here’s the point: The record for a front tire is 38 school days. The record for a rear is 18 days. The average laps per day would be around 90. I think Dunlop knows something about tires and taking up the devils advocate, these are the stickiest, most expensive ones so perhaps, at least for the quicker riders, there is economy in buying the good stuff after all.

NOTE: We change the Dunlops on our ’07 ZX6 student bikes every three or four days.

The Sticky Stuff

Everyone wants to have the stickiest rubber they can afford but it isn’t sticky until they can put the big load on the tires. Most riders would do better and learn heaps more about traction with something lesser than full race, factory rider developed tires. Why? They don’t have to put the big loads on the tires to start to experience the bands of traction as listed above.

Look at it this way. If you are using the tire at the bottom end of where it was developed by pro riders would it actually save you if you got brave for a moment? The answer is no. Pushing the loads on the tires up for a moment when the rest of the lap was at your normal pace will not give the tire enough time to warm up to the level you momentarily demand from it to handle the situation.

In other words, your potential and that of the tires have to come up together for you to take advantage of what the tire has to offer. To a large degree, the security of the stickiest rubber is false. Until you arrive at some consistency in your levels of speed and lean angle and throttle control and the other technical parts of riding it is no more then blind faith.

Trusting the Tires

In the end it isn’t about the tires it is about the rider. It’s about using good technique and having good technical skills. It’s about gaining some consistency with them and knowing you can do it. After that, it’s not so difficult to trust your tires because you trust yourself.


Keith Code

Copyright 2007, all rights reserved. No part of this article may be reproduced by any means without express written permission of the author.
[/quote AS usual you give food for thought,perhaps you could take it further and describe in your own inimitable style the sensations felt when approaching these limits.I don't do much track riding but I've been riding sports bikes without any breaks for the last 26 years and as ahabitual suspension twiddler for the last 15 I've experienced the edge more times than is healthy.The three main types are the "oh my god Ican see the tailpeice(too much preload)and "what up this things not going forward"(too much rear comp) and by far the most enjoyable(if your not chasing lap times)the fast constant radius where you're working the steering so hard to keep it down in the corner you feel sure the first thing to let go will be the front but slowly the limit arrives as a gradual lightening of the rear(little too much preload up front).Anyhoo the suspension settings arent really my point the first one I suppose doesn't count as there is no sensation except mabye hot and wet but the other two are directly related to throttle input and not at all scary.The last one in particular I found out later through video footage the rear was leaving rubber on the road through some seriously fast corners and interests me the most.As I've said I'm just a guy who rides on roads for pleasure,I love riding fast but am fairly cautious by nature and won't put myself into a situation I don't think is safe.So why in this situation do I feel it's comfortable and safe to explore the abilities of the tyres in an enviroment which would by many considered to be completely wrong.Since learning this I have observed other riders of bigger sports biikes(I've been riding 750s for the last 15 years) leaving short strips on initial acceleration and some of the quicker riders leaving them as they exit a corner and hit the throttle but I don't think they even have time to feel this and they're not really exercising any control over the situation because it really doesn't warrant any.I know both theirs and my tyres aren't sliding in these situations and it's just the top layer of rubber stripping away but there is a difference in doing it for 200m at 130mph and snapping the throttle a bit quick on a 1000 cc.Please note this isn't about percieved riding skills(I'm long past that)It's about percieved traction and why some people read it different from others.I realise that racers mostly find it by necessity(sink or swim)but for me there is no pressure only pleasure .

[tenaciousjay]

Wait, so just to make sure I'm understanding this correctly, it's normal for the tires to slide a bit? I only ask because I had a track session last year where my back tire start to "walk" on me so I immediately straightened the bike up (luckily I was mostly thru the turn and didn't have to run off the track). I don't use my rear brakes on the track and try to use gradual steering (aside from the quick turn-in) and maintain good acceleration/deceleration control with small inputs but got wigged out a bit from the tire moving on me like that. But according to your article it sounds like maybe I wasn't as close to wiping out as I thought and that eventually that may be a point that must become comfortable if I were to get involved with racing?

[Cobie Fair]

Tenaciousjay,

What exactly do you mean when you say "walk"? Did you have one little slide, did it step out a few inches, or a nice progressive slide that lasted a while? What did it do? Per Keith's article, you have to "clean" the tires to get to the new rubber. At many of our schools students have been surprised when I've informed them they were leaving grey lines coming off the turns.

Cobie

[davep]

I just want to say that I'm getting ready to attend my next session with you guys in December at Infineon, so I just filled out my questionaire a few weeks ago. Sometimes it's a little challenging to answer the questions with any precision...but this article on The Bands of Traction - has crystalized my thoughts and what I will be communicating to my coaches when I arrive. It was the perfect thing for me to read at the perfect time!
I can never thank you all enough for the learning!

dp

[jbazz]

This summer I completed my first season doing track days exclusively. I started in the novice group and graduated to the advanced group. I have a 04' cbr 1000rr. My first three track days I rode on my street tires because I wasnt serious about track days as I am now. As my pace came up I found it very difficult to maintain the line demonstrated by the coaches of the club. I could feel the gradual sliding of the tires as I increased my speed in the turns. A good friend and veteran rider reccommended I invest in the Dunlop D209. I did and everything changed...I was able to hold a decent line, my confidence soared, and my pace notably increased. At the track you hear talk of heat cycles, cold shear, tire warmers, etc. My buddies are telling me I need warmers to reduce the heat cycles of my tire and it helps the tires last longer. Correct me if I'm wrong, The way I read this article is even if I had warmers to reduce heat cycles which would preserve the tires grip overall, if I'm not riding at serious enough pace the tires may not be getting to thier optimum temperature that would offer maximum grip. As you may already know, when doing track days we have to grid up and wait for the track to be clear before being allowed to go out. Are'nt the tires cooled off during that waiting period and basically rendering tire warming procedure useless? Will a warm up lap or two be the same as using warmers? And how much of a factor does the temperature of track affect traction.

Thanks

JB

[bpez]

davep, on Oct 9 2008, 08:46 PM, said:

I just want to say that I'm getting ready to attend my next session with you guys in December at Infineon, so I just filled out my questionaire a few weeks ago. Sometimes it's a little challenging to answer the questions with any precision...but this article on The Bands of Traction - has crystalized my thoughts and what I will be communicating to my coaches when I arrive. It was the perfect thing for me to read at the perfect time!
I can never thank you all enough for the learning!

dp

Questionaire? Is that just for L4? Thanks in advance.

[Kevin Kane]

Quote

Questionaire? Is that just for L4? Thanks in advance.

Bpez;

Yes; level IV is where you help structure your own cirriculum and it starts with your Level IV Questionaire. Your Level IV Liason will sit with you at the start of the day to determine the most effective way to accomplish your stated goals. What I found is through their vast experience, they will get you there but not necessarily how you anticipate it would happen.

When you get to Level IV, take the time to really think about the questions before you answer them because it will pay bigger dividends if you do.

Kevin

[Cobie Fair]

JB--with our coach bikes we don't have tire warmers, and usually a lap or 2 will get them up to speed. Very cold days, and if it's windy, that cools the tires down, surface temperature can be a factor. We just start out easy and warm the tires by using them, working them in the turns, gradually increasing the pace. By 2nd lap you shoudl be pretty much up to pace, and the tires too. If you pull over, come in for a minute or 2, then bring the pace back down a bit, re-warm the tires. They won't be fully cold, but will have cooled.

I've heard the tire warmers help with the heat cycles, but haven't confirmed that it's really so.

Best,
Cobie

[Cobie Fair]

DP--the questionnaire for L-4, that gets us started, and gives a decent overview of problem areas. After the day is started, using that info, plus what you and your on-track coach observe, that dictates how it usually goes. The level 4 consultant is the final person you'd go over what you had done, and what you'll do next, you and he will arrive at the next assignment. Basically a coach-athlete relationship, and you'll have 2 (one coach, and the consultant).

Best,
Cobie

[Jaybird180]

Moved

[Mayo]

Im fairly new and please excuse me if I sound naive, I am hear to listen and learn, please pass on the knowledge.

So, Ive taken Levels 1 & 2 late last year and I am going to sign up for Level 3 soon. I see coaches riding the same machinery (ZX-6) and same tires (Dunlop Qualifiers) as we (students) do but the Coaches achieve much higher lean angles and faster corner speeds.
I started attending Trackdays this year almost every weekend and I keep getting negative comments when I use Dunlop Qualifiers and my friends are using Dunlop 209 or Dunlop 211, some even use Slicks. I always defend my tire choice that these tires are slightly more affordable to me (every penny counts), that I dont have the ability to use what the 209/211/slicks have to offer and that they offer more than I could ever achieve anyway; but they come back saying that the tires they use provide them the security of being Sticky tires. My friends and I ride in Novice to Intermediate, but sometimes, it all comes together effortlessly and I can ride at the tail end of the Advanced group but I dont do it too often. Anyway, my point is, Im not a racer, I dont go out to trackdays to beat on everyone because I cant. I go out and ride with the mentally of enjoying the ride, play with friends at a safe environment and try to learn & improve to something. I ride an older bike and use the "inferior" Dunlop Qualifiers and yet, go around a track just a smidge faster. It just irks me that they wont stop. their silly comments. Am I wrong for not using the more superior tires Dunlop offers for a few dollars more?

What can I say to these friends of mine to stop bugging me about tires. They also preach that I should use tire warmers to prolong tire life and reduce heat cycles but it isnt so as Ive read here. I believe Ive said whats on my mind, please tell me what you think!

[Cobie Fair]

Mayo, on Sep 23 2009, 07:14 PM, said:

Im ?

What can I say to these friends of mine to stop bugging me about tires. They also preach that I should use tire warmers to prolong tire life and reduce heat cycles but it isnt so as Ive read here. I believe Ive said whats on my mind, please tell me what you think!

Hi Mayo,

There are a few things we could go over in your post, but lets take a look at the Qualifiers, versus other tires, (Sportmax GPA, slicks, etc.).

The Q is a pretty amazing tire. I don't spend much time on other brands these days, but we have had to ride our camera bike, and chase guys on slicks with Q's, and do it no problem. One place the Q's are flat out better than race tires, is a cold and/or cold and wet day and when you don't have as much time to warm them up. We did a school earlier this year, and the coaches were all on 209/211 or cut slicks, and the students were on Q's.

I had a fast student, going very well, continued to improve. By the end of the 2nd day, in his last session, I couldn't pass him: he was on our bike, it was steady, he was going good. Mine was sliding all over the place. The slicks never did heat up, tire warmers is not an option for coaches who are on an off their bikes for 14 sessions in a day.

At the ultimate pace, more is possible from the race tires in terms of grip, for sure. But for many riders, being able to use it, the extra cost, and the fact that the Q's warm up quicker and work better in cooler conditions, there is a solid argument to use them.

As for convincing the other guys: as a Superbike School student, you get the killer price on tires from us, maybe you could just ask them what they spent on their tires, and compare that to what you spend?

[Mayo]

Thanks Cobie. See you guys soon! I cant wait for Level 3. Surely, I will bring friends to attend CSS again