I have been getting heavily into car setup, studying, testing with motec and sorts. My question is Ive read that 170 psi is optimal tire pressure. Now pressure has many variables like ambient air temp and track temp. When @ palm beach when I get the tires @ about 180 PSI Im faster than with 170 PSI. Does that mean I should run @ 180 or should I shoot for 170 or is there calculation were the track and air temps are involved thanks for any advice on this subject Rfactor2 has taking over my computer and nothing will stop it!
I would also like to know how to discover optimum tyre temperature. Shouldn't that info be integrated into the mods somehow instead of having to do hours worth of trial and error?
In rf optimum pressures are calculated by loading. If you open a tdf the parameter is: OptimumPressure=(157.0, 0.0161) // Base pressure to remain flat on ground at zero deflection, and multiplier by load to stay flat on ground first number is in kPa, the next multiplies by N 157+(Load*.0161)=Answer (kPa)
I don't know how rFactor calculates optimum pressure, but in the real world it would generally be when the middle of the tyre temperature is the average of the inside and outer tyres temperatures. The idea is that both the edges of the tread and the centre of the tread carry a proportional share of the load. This however may vary depending on lots of variables, including the elastic properties of the tyre such as effective friction coefficient, aligning torque, the tyre drag (rolling resistance and induce drag from cornering) and tyre ride (tyre spring rate) to name a few.
The optimum pressure and temperature is the one that wins you the race; Math is just a silly distraction
sorry i meant KPA I have an old GTR motec guide that ive been studying in it it states that for GTR 170KPA is optimal warm tire KPA . I know that this is is not very important when doing short 10 lap races but Im planning on racing 60 min+ races and tires are one of the most important parts of the set up. lordpants, you state to open the tdf I noticed in motec that there is a tire load parameter and rfactor exports that data Im would assume this could be used I would just have to average out the load data during the course of the lap correct?? thanks for all the help everyone
Verily. Tyre pressure is always a function of tyre temperature which is dependent on the setup and driving style. Like PLAYLIFE said, as long as the pressure is so that the temperature of the middle portion of the tyre is sitting somewhere between the inner and outer portion you're pretty much golden. If the course has next to no corners but does have long straight, then extra pressure can help with top speed, but other than that aim for balance.
Quick example would be NASCAR, where every NASCAR team (except start and parks) will run their left tires below the recommended minimums at least once each season. It is pretty widely known, as often it does result in tire failure. It's important to understand the definitions here. The optimum for the TIRE (sometimes purely safety related), versus the optimums for the CAR (including driver, setup as you said) and track on any given weekend. If your car can go faster with pressures outside optimum range, you'll do it. And basically, that's what the OP needs to do, too.
I just make a math for each wheel, then turn on measurements (M Key) and compare averages. It depends on how sensitive the tire is to pressure. The parameter for that is: GripTempPress=(1.4, 3.4, 0.65) // Grip effects of being below temp, above temp, and off-pressure (higher number -> faster grip dropoff) As you can see the tire I am pulling data from isn't very sensitive to pressure. So my avg front optimum pressure of 206.45 kPa compared to measured of 229.19 kPa isn't really doing a whole lot. I was already scorching the LF @ 186 kPa, dragging around a softer tire probably isn't going to do much for me. Using pressure to get the correct temp is far more important. rf is a program and the backside of it is math. Once you understand what is required, you can use that to figure out how to setup your car. Math is a very good starting point when you have no mfg to give you recommendations to start with. Now with rf2, I'm not sure how this applies. Obviously there is still the tdf, but if that is mostly used for the AI... ?
so keeping all warm tire pressures the same (Balance) and following the rules for tire temps will get me faster lap times thanks! I have a setup with the gtr @ palm beach where after ten laps all tires r @ 180 kpa with temps varying so im going in the right direction I will just experiment more with pressures . Lordpant i understand your maths but i haven't done much of that in motec because Im still learning and trying to understand what im looking at is there a link you could post so i could read up on maths? I m a surveyor by trade so i like math thanks
Forgive me for the stupid questions, tyres are one area of a setup that I'm yet to understand. Doesn't every racing tyre have an optimum temperature window which will provide maximum performance? My understanding was that there's a sweet spot that a driver/engineer will aim for, somewhere in between too hot (more degradation) and too cold (no grip). In which case, wouldn't each team enter a race weekend with a solid knowledge about where they have to aim for in terms of temps? That's what kind of confuses me, not having any indication of where that sweet spot is. Am I underestimating the complexity of the matter? I recall some rF1 mods displaying an optimum temperature in the garage menu, I feel somewhat lost without it there in rF2.
That's really the thing, what does optimum mean? Does it mean performance? OK, well performance LENGTH or performance SPEED? You can change pressures in a way which allows you to go faster, but increases wear, you can setup your pressures in a way which does the opposite. Which is optimum? Both are. It's your strategic decision.
Different kind of compounds have different optimum temperatures just like you and Tim describe. You're a bit underestimating the complexity too, because with choise of tyres, you're playing with strategy too if you're serious. You're testing and judging things like: In race, is it worth to drive 2 pitstops with mediums and the last part of the race with softs, or 1 pitstop with hard tyres and 1 part with soft ones. Or if you're having a race with 2 pitstops, is it worth to fill in some extra fuel, and drive 1st part with hard ones for longer drive, and last one on softs with lesser fuel in hope that other players have driven their finest already and are bit tired and make mistakes more easily, so you can make the succesful attack for better positions. Or should you do things other way round and make the attack first and hope that you can hold it out at the end of the race. Or should you balance the race and drive it with mediums in both parts and trust that you can get enough lead from the others in the 1st part so you can keep things together. And then there is the fact that we have rubber laying to the track from the tyres, so is it faster to drive the clean track with softer ones and go for harder ones when the track has been covered with rubber. This applys to a track that has lot of fast corners, that you can't make in full speed with hards (or mediums or softs) when the track is clear, but you can make them in full speed with the hard (or medium)tyres when the track has rubber on it. And if the hard ones last significantly longer than mediums, it's really good thing to test. After that there is the forecast, is it colder when you start the race and hotter when you're finishing it or is it the other way round? Is rain going to cool down the track at some part of the race? And then in really long 1 driver endurance races there is the time when you're calculating when it's the best time to attack and best time to drive less aggresively to calm yourself so you won't be trying too much all the time and end up with car bent around an ARMCO barrier. The less you have speed, the less you stress the tyres, so if you back down a bit, are the tyres still working too hard or in the optimum temperature or can you go for harder ones if they go too cold. It's pretty easy when you have 2 or 3 kinds of compounds. When you have more of them it gets more complex. At the end of the day, you're going to end up spending DAYS with testing what works best for the race before you're getting the hang of things, AND IF (...highly unlikely...) the driving gets really, really serious and races are really long and battles are fierce and close, you'll possibly need a week or two just to have a shot for the podium when it's your first race on the track. After that theres still work for atleast one day to get things straight, even if you have the data and experience from the last race you had on that track. Unless everything stays the same. Then you can go with the old strategy, or if you have evolved as a driver, you can try something new. But it'll be much more easyer second time around when you already know so much without testing. That's why i'm rather driving sprint styled races that don't need pitstops, it gets too serious for me. But it would be fun once in a while to drive some longer races and to learn how to do these things properly too. Suspension and chassis, that i can pretty much handle, but tyres, that is the one spot that i don't want to go, atleast alone and without a tutor. I hope i'm not mixing your head too much, because this rabbithole is really, really deep if you want to master it. Engineer deep if you do it for living.
Speaking to an old mate of mine at the Australian Grand Prix who works for Williams, he said the Pirellis have a 'operating window' of around x°C. By 'operating window' he means highest grip level. Inside that window there's other 'windows' where the tyre experiences varying characteristics which may or may not suit the car/driver combination. So once you're in the working window, it then is all about getting the tyre to work with the suspension/chassis etc. most effectively for desired handling characteristics. Outside that window, grip is markedly lower and you're going nowhere fast. Hence the importance of keeping the tyre at 'operating temperature' because outside of this the grip levels are seriously uncompetitive. Tyres should not be thought of or taken as a single entity. Their function and 'working conditions' are very much dependant on the car itself. As we've seen in Formula 1 over the last few years more clearly than any other season, certain cars can't make the tyres stay in their operating window under certain conditions. That is a function of the car (suspension, chassis etc.) imparting it's characteristics on the tyres. Then there's the snowball effect which occurs sometimes, where the tyres aren't in the operating window so the car's suspension/chassis don't create the loads they were designed for which causes the tyres to continue to get farther away from the operating window so on and so forth - a vicious circle.
That's essentially what I was wondering about. There's a good article on F1.com that explains it in layman's terms. It goes on to state: Hence my confusion, and earlier post: For example, when doing setup work in LFS you are presented with some useful info regarding the tyre compounds and at what temperatures they have been designed to operate in and around. So when I'm setting up my Formula BMW I know that give or take a bit, the SLICK_R2 compound works best around 85 degrees. From there I could tweak other elements of my setup to treat my tyres more considerably, or I could have a hotlap setup that would burn them up in no time, but it's great for qualifying. This is why I say I feel lost heading into an rF2 session, because that information isn't provided anywhere. I would imagine that real racing teams are given some numbers to work with by their tyre manufacturer, so they're not flying completely blind. I understand that tyre strategy and setup is essentially a bottomless pit with so many variables having to be taken into consideration. But I can't understand why a temperature window or good average temperature for the compound your car has fitted isn't stated anywhere in rF2's garage menus. Again, my apologies if all of this sounds stupid. I consider myself a good racer but by no means a master of the setup. A little display providing this information would be very useful for people like myself who are comfortable tweaking a setup to their liking, but aren't bright enough to delve into the maths and science of it all.
ROON I agree with you. No matter what tyre compound, there will always be optimum conditions for it. Road car tyres can have huge ranges like -50°C to 150°C (example) so it's not really specified since it will work in all conditions (although I would probably argue that it would work better in sub-windows). As for rF2, I haven't bothered with intricate setup and tweaking at all since the physics are not finished yet. Anything I may learn now may very well be useless when it goes gold. So I can't really add anything rF2-wise. We don't yet know exactly what has been implemented but have been told the tyre model is not finished so I probably would steer clear of reading too much into anything about it right now.
You couldn't get 180 PSI in an automotive tire. It'd burst before then...way before. We run 10 ply aircraft tires at less than that.
