Register    Login    Forum    Search    FAQ

Board index » TRACKWHORES.COM - General Discussions » Tire and Suspension Tech




Post new topic Reply to topic  [ 6 posts ] 
Author Message
 Post subject: Dunlop Tire Info (compilation direct from Dunlop)
 Post Posted: Mon Jul 11, 2011 10:48 am 
Offline
Site Admin
User avatar

Joined: Wed Apr 22, 2009 1:27 pm
Posts: 3474
Current TrackWhore(s): Daytona 675 (track) R1 (street)
Bike/Plate #: 369
Stole this stuff from another forum. Info provided by:

Steve Brubaker
Dunlop / Race Tire Service
Distributor for Dunlop Motorcycle Road Racing Tires,
Eastern USA

Some great info from someone that should actually know WTF he's talking about...

_________________
Image

Ἢ τὰν ἢ ἐπὶ τᾶς

www.WickedRacing.com - Go Fast Parts & Gear for Riders and Their Motorcycles
PM me for "TrackWhore" special discounts


Top 
 Profile  
 
 Post subject: What Dunlop tires are available for track days?
 Post Posted: Mon Jul 11, 2011 10:49 am 
Offline
Site Admin
User avatar

Joined: Wed Apr 22, 2009 1:27 pm
Posts: 3474
Current TrackWhore(s): Daytona 675 (track) R1 (street)
Bike/Plate #: 369
Steve Brubaker:

Dunlop currently has 4 usable tire choices for track days -


Q2
D211GPA
D211GP
N-Tec slicks.



Q2 is the top of the line sport/street tire. Excellent for street riding. You can use it for your first couple of track rides, but the moment you start to get with the program you will want to step up.

The D211GPA is the spec tire for the AMA. it is lower cost, and is a great all around tire. The AMA guys are right on the track record with this tire and there is no reason you can't go very fast on it. Use the Med front and rear compounds for track days.

The D211GP UK N-Tec, this tire will cost you more, about $125 more than D211GPA. It is good for about 0.5 seconds per lap faster than the D211GPA (depending on the track, may be less at some tracks). This tire will last longer than the D211GPA and you will get more competitive laps from this tire. The increased cost is about the same as the increase in laps. Its a toss up if you are looking at the laps/cost issue. you need to try them both to determine on your bike which is the best bang for the buck.

The N-Tec Slicks.
Top of the line. Nothing available is better, and I mean NOTHING IS BETTER. This tire will last longer and grip better, for more laps, than anything available.

All these tires are great choices for track days. You can't go wrong with any of them. I recommend to start at the top (Q2 or D211GPA) and if you like it stay with it. If you desire more as a rider, then step up to the next tire.

BTW: the lower 3 tires have the N-Tec construction, the D211GPA does not use the name N-Tec, but is still the N-Tec construction.

Beginner groups: I would stick to the D211GPA and keep it simple. Put in lots of laps.

_________________
Image

Ἢ τὰν ἢ ἐπὶ τᾶς

www.WickedRacing.com - Go Fast Parts & Gear for Riders and Their Motorcycles
PM me for "TrackWhore" special discounts


Top 
 Profile  
 
 Post subject: What is the right pressure?
 Post Posted: Mon Jul 11, 2011 10:53 am 
Offline
Site Admin
User avatar

Joined: Wed Apr 22, 2009 1:27 pm
Posts: 3474
Current TrackWhore(s): Daytona 675 (track) R1 (street)
Bike/Plate #: 369
Steve Brubaker:

What is the right pressure?

Lets start of by establishing some basics.

#1, we need to understand that every tire may perform differently at different pressures. What works for one tire may not be the very best for another.

#2, Splitting hairs on tire pressure is not going to part the Red Sea. Meaning, 0.5 Psi or 1 Psi change in pressure is not going to change your lap times by 2 seconds or more. So keep perspective, if you ride 15 seconds off the track record your not going to magically go 10 seconds faster with small change in tire pressure. Stick to the recommended till you are going very fast.

#3, Higher pressure increases stability at the cost of traction. Lower pressures increases traction at the cost of less stability. There is a workable window here, so don't get extreme variations from the recommended.

#4, Tire pressure and tire temperature are linked. As the temperature of the tire rises, so does the pressure. Don't try to control this, let it happen, its normal.

#5, (and most important) keep your tire pressure set point consistent. Don't change from cold to hot to off the track. pick cold or hot and stick with it.

Definitions:
Cold pressure is the pressure you set the tires at if they are cold. The temperature without warmers, just sitting there in the pits or in your garage.
Hot pressure (also called off the warmer pressure ) is when you set the pressure on the warmers, when the warmers have been on for 45-60 minutes and the tire is up to temp.
Off the track pressure is the pressure of the tire as it comes right off the track after several laps.

The urban legends say many different things:

-some say only check hot
-some say only check cold
-some say check them cold, then check them hot, then reset them when they come of the track
-some say to adjust the pressure till the hot and off the track pressures are the same
-some say make the warmers hotter if your don't get a 2 psi rise from cold to hot.

These are all methods people have used. lets let these go and start fresh. They are not all correct.

Lets look at track day pressures for D209GPA, D211GPA, D211GP N-Tec and N-Tec Slicks. BTW: all of these have N-Tec construction.

The recommended Hot is 33 front and 23 rear. That is hot off the warmers. Don't change or reset them. You are done. That's it. That's all you need to know! Go ride. Ride all day.

Q&A:

What if I want more grip? what if i want more stability? Refer to #3 above - take out 1-2 psi for more traction, add 1-2 psi for more stability, but do this only hot off the warmer.

Why check them hot off the warmer instead of cold or off the track?
Because the temperature on the warmer will ALWAYS be the same, it will ALWAYS repeat the same temperature, that gives you a BASELINE TEMPERATURE to then set your PRESSURE.

But the pressure went up when I checked it off the track, why don't I change it then?
Because the pressure off the track is linked to the temperature off the track. That temperature will vary from lap to lap. Higher for fast sessions, and lower for slow sessions. You will forever be chasing a stable point to set your pressure if you check them based on the off the track pressure. The off the track pressure is also after the fact, you are done on the track, checking or changing the pressure then will not change the lap times you just did.

I just got off the track and need to make a 2 PSI change NOW and go right back out, I can't wait 30-45 minutes for the tires to stabilize on the warmers to make the change, what do I do now?
Check the pressure right now, whatever that reading is, make your change (add 1-2 psi or remove 1-2 psi). Note the change ( + or - ) as your NEW hot off the warmer pressure. Example: After riding you feel a 1 psi change higher is in order. you started hot off the warmer at 23 psi, checking the off the track pressure its 27, you add 1 psi making it 28 psi, note down that your hot off the warmer pressure is now 24 psi, go back out. The next day you ride, set your hot off the warmer psi to 24.

I am going 15 seconds off the track record. I am running the recommended PSI that is on the http://www.dunlopracing.com website. but I think I should be able to go MUCH FASTER if I change my tire pressure. Should I lower the pressure to get more traction and faster lap times? NO, NO, NO! At those lap times, varying from the recommended will not gain you what you are looking for. Stick with the recommended till you get within 5 seconds of the track record, then start making small 1 psi changes. Only make more changes if you can feel the difference in 2 psi up or down. if you can't feel that change, then that change is not helping you, go back to the recommended.

Everything is working good. I love my bike settings, my tires are working great, the Saturday track day was awesome. Now on Sunday the weather is 10 deg hotter. Do I change the pressure to compensate? NO! The pressure will affect the handling and stability of the bike far more than the running tire temperature. When you make a psi change you are also affecting the setup of the bike.

I am a slow rider, I am 20 seconds off the fastest pace. I can't seem to get my tires very hot. Should I lower the PSI to get more heat into the tire? NO. Again changing the PSI will affect the handling and stability of the bike more than the running temperature. The big thing to remember is not to put the cart in front of the horse. You are NOT trying to achieve a certain temp or psi. Your tire temp is a RESULT of you riding fast or slow. Yes, fast riders have higher tire temps, but not all high tire temps = going fast. Yes you can do things to the setup and psi to get the tire to run hotter, but that would not be a guarantee of faster lap times. that logic would be like "Ben Spies puts his right finger on the break lever, Ben wins races, I will put my right finger on the break lever, I will win races". Not logical or workable. If you are a slower rider you will not have as much heat as a faster rider, but at a slower pace you are not using the same level of grip as a fast rider. You are concerning yourself with something that is not a problem, spend more time on the track doing laps and improving as a rider. Use the recommended PSI till you start going faster.

I don't have warmers. what do i set my pressure at? Set your pressure at 2 psi lower than the hot recommended pressure. Take 2 laps to get some heat in the tire before you start pushing it. Generally you will get a 2 psi rise from cold to hot. The variable is the outside temperature. Could be 40 deg or 90 deg in the morning when you check it. that is why checking it on the warmer is more stable point to check psi. Cold temps always have this variable attached to them, but this in not more than 1 maybe 2 psi. 1-2 psi would not make the difference in a rider going 15 seconds off the pace, so don't go overboard here. just check it, do 2 warm-up laps, and then ride.


Lets talk about pressure changes as the temp increases:



Generally, you will see 2 psi rise from cold to hot off the warmers. If you have warmers there is no need to check them cold. 45-60 minutes on the warmer and then check them hot.

Fast riders may see 2-3 psi front and 3-5 psi rear rise from hot off the warmers to off the track. there really is no need to check the off the track. It is more important to listen to the rider and what he feels is going on. If the rider likes it, leave it alone. This is important: you only need to check rise to make sure there is not a very big rise 9+ psi. Check it once and no need to keep checking it. you are more likely to lower the psi from checking needlessly many times.

If by chance you get a very large rise, 9+ psi, you probably have excess humidity in your tire, the tires are getting very hot or you have stock or bad suspension. You need to replace the air in the tire with dry air from a better compressor or put dry nitrogen in it. This condition will only happen if you have high temps at track like Daytona, Willow Springs and others. If this condition is occurring, and you are a fast rider, you need to be in direct communication with your tire supplier for tech advice and not on a forum.

_________________
Image

Ἢ τὰν ἢ ἐπὶ τᾶς

www.WickedRacing.com - Go Fast Parts & Gear for Riders and Their Motorcycles
PM me for "TrackWhore" special discounts


Top 
 Profile  
 
 Post subject: When Should I switch from Q2 to Race Tires (D211GPA or bette
 Post Posted: Mon Jul 11, 2011 10:54 am 
Offline
Site Admin
User avatar

Joined: Wed Apr 22, 2009 1:27 pm
Posts: 3474
Current TrackWhore(s): Daytona 675 (track) R1 (street)
Bike/Plate #: 369
Steve Brubaker:

When Should I switch from Q2 to Race Tires (D211GPA or better)?

You must evaluate what it is you are trying to accomplish with the tire to fully answer this question.

Do you want the best lap time?

Do you want the tire to last the longest?

Both are valid goals, and the choice should be simple, but... Riders often get confused by the urban myths: That tell us we must have a certain lap time or go at a certain pace to get heat into the tire or you will not be able to truly use a race tire. That you wont be able to get heat into the race tire. That you will fall down because you can't get the race tire up to temp. These are myths and exceedingly over emphasized.

The reality is, you can use race tires at ANY pace. Even a slower rider can use a race tire without issue.

Will that slower rider get as much heat in the tire as super fast rider? NO.
Does he need to get heat in the tire to ride at his slower pace? NO.
Does the tire still grip when not fully up to temperature? YES, certainly it does. Maybe not as good as fully hot, but it still grips well.

If you took a rider with a race tire and had him go 5 seconds off the class record, the tire would be well up to temperature and there would be no problems.

Now have that rider go 6 seconds slower, now 7, then 8, 9 ,10, 11... 15, 16, 17, 18... Now at what point do you think the tire would not grip and he would fall down? ANSWER, NEVER. You could do this in reverse, starting at 60 sec off the pace then going faster without issue.

As the pace gets slower, the temperature get less, and so does the DEMAND FOR TRACTION. Certainly the rider at 5 sec is demanding much more traction than the rider at 15 sec.

So where do we get into trouble? Why do we hear all about having to get heat into the tire or we fall down. It comes from the "demand for traction" conflicting with "available traction". Or simply put, "The rider went faster than the tire had traction". its really that simple.

Example: Rider A goes at 5 sec off the pace, no problems. We know he has good heat in the tire. His buddy, rider B, goes at 12 sec off the pace. Less heat in the tire. The next session rider B then attempts, on his first lap, to go as fast as rider A does, and falls down. He blames the "race tire" for not having enough heat in it. He then tells this story over and over, with emphasis on that "Cold Tire". Now riders are all worked up about race tires and getting heat into them.

If a rider progressively increases his lap times, the heat of the tire will increase right along with it, and with that will increase the traction.

So the answer to this question is you can change at any time to race tires. You can start on race tires on your very first track day.

FACT: If you had 2 identical bikes with similar caliber riders, one on Q2 and the other on D211GPA, the rider with the D211GPA would have equal or better grip, at every temperature, from room temperature all the way up to race pace. With the Q2 increasing in performance moderately, and the D211GPA increasing substantially in performance.

Riders must use common sense when going out to go fast. Slamming into turn one at full pace with cold tires is not using common sense. But doing so and then claiming it was the tires fault is simply not accepting responsibility.

_________________
Image

Ἢ τὰν ἢ ἐπὶ τᾶς

www.WickedRacing.com - Go Fast Parts & Gear for Riders and Their Motorcycles
PM me for "TrackWhore" special discounts


Top 
 Profile  
 
 Post subject: Heat cycles
 Post Posted: Mon Jul 11, 2011 10:56 am 
Offline
Site Admin
User avatar

Joined: Wed Apr 22, 2009 1:27 pm
Posts: 3474
Current TrackWhore(s): Daytona 675 (track) R1 (street)
Bike/Plate #: 369
Steve Brubaker:

Now lets tackle the issue of HEAT CYCLES.


Heat cycling of the tire is a very confusing and misunderstood area. I will say that I have heard that other brands are well known for "going off" or "heat cycling" and I will leave that conversation to another thread another day.

For now I'm going to stick with Dunlop's, as that is what I know.

Do tires heat cycle? Yes

Is this the most important factor in tires? NO! in fact it is NOT very significant, and very over emphasized.

Certainly making a tire go from 250 deg to negative 10 deg over and over is not the best thing you can do to a tire, but consider that placing it on a warmer, at 190 deg, for 8 hours is not any better. Both extremes are not the best for the tire.

We all hear about "Heat Cycle", but almost never do we hear talk about the thickness of the tire, or tread depth/wear.

Fact: :idea:The thicker the tread rubber, the more grip. The thinner the tread rubber, the less grip. As you ride on the tire, session after session, the rubber is getting thinner and there is less and less grip. Often this is mistaken for "heat cycle", and the rider now places his attention on his warmers and not on the real important factor of how much tread rubber is left on his tire.

Odd rituals start to crop up regarding tire warmers: Riders come back to the pits and RUSH to put their warmers on and crank them up to full, all in an attempt to "stop the heat cycle!". When buying used tires, riders mistakenly rate the tire by how many heat cycles it has, not the tread depth.

It is a mistake to emphasize heat cycling over tread depth, with Dunlops.



You can use a D211GPA or any other Dunlop tire without warmers and have no problems. ( Make sure you do heat the tire up for the first couple laps before you get with the pace.)

You might have a very small decrease in grip or life, but that would be very small and most likely not noticeable over the 1-5 track days you will get out of the tires. You would be splitting hairs on the performance level and tire life with/without warmers. Even if you were to do back to back tests, you would find that if in just 1 session in the life of the tire, you went 5 seconds faster, that would make more of a difference than heat cycling because you used more tread rubber in that session.

Heat cycles are not a total myth, but they do not make as big a difference as the internet would lead you to believe.

Tire warmers are good thing to have if you want to get going right out of the pits. They are not a requirement. Note that our recommendation for track day warmers has you putting the warmers on after a session and not plugging them in right away. This is so you don't needlessly force heat into the tire continuously for no reason. http://www.dunlopracing.com/Warmers.pdf

Ever notice that the chatter about heat cycles started about the time tire warmers became cheaper and more readily available? Do you think there could be an urban legend that started because of this increased supply?

_________________
Image

Ἢ τὰν ἢ ἐπὶ τᾶς

www.WickedRacing.com - Go Fast Parts & Gear for Riders and Their Motorcycles
PM me for "TrackWhore" special discounts


Top 
 Profile  
 
 Post subject: Re: Dunlop Tire Info (compilation direct from Dunlop)
 Post Posted: Mon Jul 11, 2011 11:14 pm 
Offline
Serious 'Ho
User avatar

Joined: Wed Sep 16, 2009 3:04 pm
Posts: 383
Location: Buffalo, NY
Current TrackWhore(s): K7 GSXR 750
Bike/Plate #: 535
Great info! I read the info about heat cycles on the Dunlop earlier this year. Previous to that I was thinking heat cycles were everything. I think its great that people in the know are educating the rest of us. I wish the other vendors would do more of this too.

_________________
Ben
#535


Top 
 Profile  
 
Display posts from previous:  Sort by  
 
Post new topic Reply to topic  [ 6 posts ] 

Board index » TRACKWHORES.COM - General Discussions » Tire and Suspension Tech


Who is online

Users browsing this forum: No registered users and 1 guest

 
 

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron