Οδήγηση/Μοτο => Τεχνικά, εξοπλισμός, βελτιώσεις => Μήνυμα ξεκίνησε από: drioannis στις Δεκεμβρίου 01, 2015, 03:37:36 μμ

Τίτλος: Γενικοί κανόνες για ρύθμιση πίεσης ελαστικών στην πίστα
Αποστολή από: drioannis στις Δεκεμβρίου 01, 2015, 03:37:36 μμ

This was written by the AMA Dunlop Race Tire Rep. It's just a general guide that has a lot of good tips.

Tire Pressures

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.

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
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.

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 hot off the track, 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 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 awsome. 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, FACT. 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, Listen closer in the classroom and spend more time on the track doing laps. 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. Generaly 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.

Everything is going fine, I check my psi hot every morning, rise looks good. Then today i checked my rise and I only got 2 psi rise in the rear and I normally get 3. What do I do? Don't change anything. Don't split hairs. Refer to #2 above

Είναι πιστεύω ο καλύτερος μπούσουλας για ρύθμιση πίεσης αγωνιστικών ελαστικών στην πίστα που έχω διαβάσει.
Τίτλος: Απ: Γενικοί κανόνες για ρύθμιση πίεσης ελαστικών στην πίστα
Αποστολή από: jimmyjp στις Δεκεμβρίου 01, 2015, 04:26:42 μμ
Βασικά νομίζω ότι είναι πολλά τα 3-5 PSI τα οποία έχει αύξηση η πίεση από ζεστα σε κουβέρτες σε off the track. Έχω έχω δει το πολύ 0,15-0,2 bar το οποίο αντιστοιχεί σε 2-2,5 PSI. Ίσως παίζει ρόλο και η οδήγηση βέβαια, αλλά και το λάστιχο.

Σχετικά με την μέτρηση της πιέσης μετά από κουβέρτες 45-60 min(θεωρητικά να έχει το λάστιχο >75°) το έχει ακούσει να το κάνουν όλοι, σε πολλά πρωταθλήματα γιατί είναι δεδομένο ότι όταν θα μετρήσεις 'ζεστο' θα ξέρεις ότι το λάστιχο θα είναι μεταξύ 70°-80°. Από την άλλη όταν μετρήσεις το λάστιχο 'κρυο' άλλο κρύο θα έχεις το καλοκαίρι, άλλο το χειμώνα...Βέβαια όταν το κουβερτωσεις το ίδιο αποτέλεσμα θα έχεις στην θερμοκρασία, απλά θα χρειαστεί περισσότερη ώρα στην περίπτωση του χειμώνα. Οπότε και οι δύο τεχνικές έχουν βάση, και απ ότι έχω δει το δεύτερο δουλεύει καλά...

Όταν πάντως είχα μιλήσει με τον Steve Brubaker της Dunlop μου είχε πει ότι δεν επιλέγουν γόμες έχοντας ως κριτήριο μόνο την θερμοκρασία ασφάλτου αλλά και την ίδια την ποιότητα της και έχουν κάποια λάστιχα που standard δουλεύουν σε κάποιες πίστες ανεξάρτητα από θερμοκρασίες. Κάτι που η Dunlop Ευρώπης φέτος είπε στο ευρύ κοινό με τα chart που έχει βγάλει για τα καινούρια KR στα οποία δεν δίνει καθόλου θερμοκρασίες ασφάλτου(!) πάρα μόνο περιβάλλοντος και track severity.

Και επειδή ο Αμερικανός μου τα μασάγε όταν ρώτησα για πιέσεις αγώνα,υπεκλεψα data από το Kawasaki Team Grill που εκείνη την εποχή έκανε δοκιμές στα Μέγαρα με 4 (!) ZX 10R.

Στάλθηκε από το GT-I9300 μου χρησιμοποιώντας Tapatalk