<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RI749 »</TD></TR><TR><TD CLASS="quote">What is everyone running for tire pressure on the Pilot Powers. I have been told a million different things. I have the 120/180 set-up.</TD></TR></TABLE>
based on past responses ....are you running 5.5 or 6" rims ? you might kill your bike if you don't follow what is stated in a manual
you don't need no sticken pressure- its all based on faith man
you guys are running those low pressures on the street? these tires aren't the same as the power race. now i'm all confused cause i've been told to even keep the pressure higher than that (34-36) on the track with the street/trackday pilot powers.
Well, my justification is the tire pressures stated on your side walls are MAXIMUM pressure cold and a given MAXIMUM load.
If your bike weighs a whole lot less that the max weight why run the tire rock hard to it max capacity.
Generally they soak up bumps/undulations better, get warmed up quicker and with a single rider with the bike weight it comes in at around 240kg of the 365kg you can max load it too so based on that theoretically you could run the tire down to 28 PSI, that I belive would be slightly optomistic and quite squirmy.
that make sense but i'm not sure if that applies to these newer tires.
as you mentioned a lower pressure will soak up bumps because the sidewall/tire are more able to flex but iirc, the reasons i was given to run regular pressures is that the pilot powers (like the diablo corsas) have a very flexible/soft sidewall construction that doesn't require the lower pressures to do the things that you mentioned.
keep in mind i'm going on what i was told by local racers and my info could be totally wrong.
Its not so much as the ability to soak up undulations but more to keep the tire within the correct pressure range for the weight and accordingly the surface pressure/contact patch, that is how I understand it but that is not for track use either as I am no expert there, in fact I am no expert all round other than having riden for 22 odd years and found that to be the way, maybe for these new breeds of tires that has changed but I will prolly do the same as I have good results for me.
We need some tire experts to come aboard this discussion, I remember when I first joined SZ Dr.O and someone else had a major shouting match over it, Shazaam??
The Pilot STREET tires require a higher pressure setting than your normal tires. I confirmed this with the tire guy at the track and by calling Michilen.
When I run Dunlops, I run 30f/28r. Michilen told me NOT to run the Pilot STREET tires at these pressures. The race tires like the lower pressures, but the Pitlot STREET tires like the higher pressures.
Reason that I got(from both of my sources) was the the Pilot STREET tires do not require the lower pressure to generate heat. They do just fine in the mid 30 range. I run my 35f/35r and have had no problems what so ever. And I run my tires pretty hard(I am also a roadracer).
The answer is, for a tire to perform at its best it has to reach, but not exceed, the temperature at which the rubber compound gives the maximum grip.
The difficulty is, predicting the temperature that the tires will actually reach for each combination of bike model, suspension set-up, rider weight, cornering and throttle technique, air temperature, road temperature, road surface and curvature ... just to name a few variables. This is why tire testing is so important, and also why so much time is devoted to it by race teams.
For street bikes, Ducati plays the averages. When they do development work on each bike model, Ducati test riders and engineers work with their OEM suppliers, Michelin and Pirelli, to come up with a tire that gives a good overall performance (wet, dry, good milage, etc.) Along the way, the tire pressure that works best for these OEM tires for AVERAGE ROAD USE is determined, and that’s the number that ends up in the Owners Manual. As power increased and tire construction and rubber formulations changed over the years, so have Ducat’s recommendation for tire pressures. Early 916’s for example, had a recommended pressures of 32F/35R, but 30.5F/32R is now recommended for 99X’s.
So when you move to a tire that isn’t OEM, then you have to do your own tire testing to determine the best pressures FOR YOU, and you have to hope that the tire manufacturer has done the necessary development work to give you a good starting point.
The non-Ducati OEM tire manufacturers play the average-game as well, so when they recommend tire pressure starting points, they do it for an average bike, whatever that means. The trouble is the tire manufacturers don’t ever tell you what’s the optimum tire temperature for the rubber formulation for each kind of tire. Some reps will tell you the optimal increase (%F/%R) in pressure from cold to running condition, which is more useful information than cold tire pressures.
So it’s really all up to you. You'll get a lot of opinions on what tire pressure to run, but the correct tire pressure for you is not a matter of polling other rider's opinion or asking the manufacturer’s rep at the track.
Here are the basics you'll need to decide for yourself.
For the street, start with the bike manufacturer's recommendation in the owners manual or under-seat sticker for OEM tires and similar models from other manufacturers. This is the number that they (Ducati and the OEM tire makers) consider to be the best balance between handling, grip and tire wear. Just as you would for a car, increase the pressure 2 psi or so for sustained high speed operation (or two-up riding) to reduce rolling friction and casing flexing.
In order to get optimum handling a tire has to get to its optimum temperature which is different for each brand of tire. Most of us don't have the equipment needed to measure tire temperature directly so we measure it indirectly by checking tire pressure since tire pressure increases with tire temperature. Tire temperature is important to know because too much flexing of the casing of an under-inflated tire for a given riding style and road will result in overheating resulting in less than optimum grip. Over-pressurizing a tire will reduce casing flexing and prevent the tire from getting up to the optimum operating temperature and performance again suffers. Sliding and spinning the tires also increase tire temperatures from friction heating.
A technique for those wanting to get the most out of their tires on the street is to use the 10/20% rule.
First check the tire pressure when the tire is cold. Then take a ride on your favorite twisty piece of road. Then, measure the tire pressure immediately after stopping. If the pressure has risen less than 10% on the front or 20% on the rear, you should remove air from the tire. So for example, starting at a front tire pressure of 32.5 psi should bring you up to 36 psi hot. Once you obtain this pressure increase for a given rider, bike, tire, road and road temperature combination, check the tire pressure again while cold and record it for future reference.
Each manufacturer is different. Each tire model is different. A tire design that runs cooler needs to run a lower pressure (2-3 psi front) to get up to optimum temperature. The rear tire runs hotter than the front tire, road and track. So the rear tire cold-to-hot increase is greater. Dropping air pressure has the additional side effect of scrubbing more rubber area.
As an example, when I used the tire pressures recommended by Ducati (32F/35R) for my 916 on my favorite road, I got exactly 10/20% on a set of Bridgestone BT-012SS. So I guess I'm an average rider, and the BT-012SS runs at an average operating temperature compared to the OEM tires.
For the track you'll probably have to drop the cold tire pressures an additional 10/20%. Track operation will get tires hotter (increasing the cold-to-hot pressure range) so starting at say 32/30 psi now should bring you up to the same temperature (and pressure) that 35/39 psi gave you for the street. Don't even think about running these low track cold pressures on the street.
Finally, dropping tire pressures on street tires for track use has its limitations, so street compound tires on the track often get too hot and go beyond sticky to greasy. That's why you have race tires. Race tire compounds are designed for severe operation at these higher temperatures for a limited number of thermal cycles. On the other hand, a race tire on the street usually won't get up to the appropriate temperature for good performance. At street speeds, the race compound often won't perform as well as a street tire.
The Michelin Pilot POWER likes / needs higher pressures; eg, 35-36 f and 36-37 r COLD. This is per the track side Michelin reps, Freddie Spencer's school (FSS) -which uses the POWERS in their schools and has done beta testing for Michelin- and my own personal experience.
It's contrary to popular tire pressure folklore but it's the real deal.
The Michelin Pilot RACE likes lower pressures than normal; eg, 31 f and 22 r COLD.
After the RRW tire test came out and they reported lower pressure to use in the POWERS than what I was told by Michelin USA, the Michelin trackside reps and FSS, I called RRW to ask and they simply said "the rider like them best at these pressures."
I then called Michelin back and ask, as well as talking to my local reps at the track and FSS (again) and they all agreeded that running the lower pressures wouldn't neccessarily hurt the tires, although everyone from Michelin I talked to said it would accelerate their wear and for myself, I woldn't want to run a tire lower than what's reccomended because it'll fry the carcass of the tire and make it greasy.
Lastly, from the techs at FSS, the Michelin Pilot POWERS heatcycle out before they actually wear out. They'll still be fine for street use but they won't be optimal.
I did the legwork, made the calls and asked everyone I could : the POWERS like higher pressures and the RACE like lower pressures.
Hmmmm..... Just did a BCM track day at NHIS in Louden. Bruce from BCM reccomended running 30 front 28 rear for the Pilot Power non race tires. Of course the weather was was around 90 and the track temps were on the high side too. The tires felt good at those pressures on a hot day and a very warm track surface.
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