Reader Submission #96 – Earth to Kaemmer?


An experimental tire model based entirely on the theories of one individual’s studies is bound to cause problems, and this has been a source of continuous frustration for long-time iRacing members. Dubbed the New Tire Model project, and first launching in September of 2011, Papyrus legend David Kaemmer has embarked on a mystical journey into the depths of sim racing hell, focused solely on developing his own theoretical interpretation of tire behavior within a modern racing simulator. However, his efforts have unfortunately gone largely to waste – the perpetual science project of one man’s research into how rubber behaves under stress has warranted six builds and countless revisions that have all failed to truly nail racing slick behavior found in older simulator engines. While the game aspect of iRacing has always been leaps and bounds ahead of the competition, those who want an unprecedented driving experience are usually forced to look elsewhere due to a tire that’s never felt quite right, and in some cases, extremely wrong.

And there’s a reason for that.

He’s not much of a reader, but Jake C. has sent us in a hilarious forum capture, indicating the mastermind behind several Papyrus simulators appears to have lost his way. And sadly, even when Kaemmer is 100%, unquestionably wrong in his theories, those who have sunk several hundred dollars into the service still bend over backwards to defend him at all costs in a glorious display of Stockholm Syndrome.


I’m not a reader of necessarily, but I do get a laugh out of some of the things posted. I’ve always hated iRacing. It’s an immersive game, and that immersion tricks people into thinking it’s realistic. It wouldn’t be so bad, but the guys there throw money at their rights and have no idea what acceptible Force Feedback feels like, and shit talk all other sims as if they were arcade games with such vehemence. I’m sharing this with you because it’s bullshit. And not many people have the balls to say anything in public about iRacing. Hell, a lot of the pro drivers fucking hate iRacing’s physics, but they shut up and put up with it because it’s not like rFactor offers $10,000 officially licensed championships.

Anyways, some guy on the iRacing forums had a problem with negative camber setups producing outside shoulder tire temperatures that were much too high. I mean, the tires literally weren’t cooling down at all, even though they were being blasted with air and physically not touching the ground.


David Kaemmer, the man himself, comes along to say that the outside of the tire shouldn’t be cooling down.


This is totally false. In fact, another user in the thread posted a video of Paul Di Resta running laps with a thermal camera attached to the car, which shows that tire tread not in contact with the road will cool down faster than tire tread that is touching the ground. But of course, iRacers are coming up with all kinds of bullshit to support iRacing and David Kaemmer.

Now obviously in the first few seconds, you can see the tire blankets come off and the temperature doesn’t change much. But as soon as he starts driving, they begin cooling down. Yet according to David Kaemmer, airflow making contact with the tires doesn’t cool them down at all! I just don’t get how people can even form an argument against the Di Resta video. But the brainwashed iRacers certainly tried anyways. And typically, they make anyone who speaks out against the glorious iRacing overlords to be outcasts and conspiracy theorists. As if they are saying they were abducted and anally probed by a pack of aliens.


Away from the iRacing forums, where you’re instructed to bow down to Lord Kaemmer, this is even being laughed at on Reddit – which is usually full of iRacing apologists. A portion of a tire that isn’t touching the ground isn’t subjected to friction, but is subjected to air cooling. Convection happens as the temp is essentially chased from the outside of the tire to the inside where it remains touching the ground. Now it’s okay to prefer one thing over someone else based on opinion, but it’s another to say that you value realism and factual data over everything else but then warp your version of reality when something factual doesn’t fit the narrative of iRacing.


This isn’t surprising. David Kaemmer thinks a NASCAR tire should never reach over 220 degrees without losing grip, yet they are constantly hovering around the 280-300 degree mark in real life. He’s also got no idea how centrifugal force works on a tire at speed, but that’s a story for another time.

So as usual, the fanboys just assume Kaemmer is correct, and find any way they can to defend his findings. The scary part is, half the people in the physics forum say how amazing and brilliant Dave is for knowing stuff even real race teams don’t, but for whatever reason, this knowledge is never translated into a competent tire model after how many builds now? iRacing’s got seven different tire models with this allegedly cutting-edge information from our collective Lord and Savior, yet all seven of them drive in a completely different fashion and give extremely different telemetry readouts.

The best question to ask, is how many other little errors have been made within iRacing’s current rendition of their perpetual tire model project, if mistakes this blatant are deemed acceptable.

  • Guy says the outer edge of his tires, which aren’t touching the track, aren’t cooling down.
  • David Kaemmer says tires don’t cool down even if they’re not touching the track.
  • An F1 thermal imaging video is posted to prove that portions of the tires not touching the track do indeed cool down, proving Kaemmer wrong.
  • Fanboys bully the OP and claim Kaemmer is right anyways.

What is New Tire Model V9 going to look like? What about Version 11? What other shit is going to pop up for iRacers to discover?


62 thoughts on “Reader Submission #96 – Earth to Kaemmer?

  1. (a) Air does not conduct heat well. It’s fuckin’ well known for this insulative property. So yes, heat will transfer from tire to asphalt more easily than from tire to air.
    (b) However, track surfaces run a lot hotter than the air even a foot above the surface. Heat transfer is proportional to the difference in temperature, which compensates a bit.
    (c) if iRacing’s telemetry is not showing the surface temperature, then the video is irrelevant. (From the names ‘R M L’ I can’t tell)
    (d) The bit you mentioned at the start, about the tire staying warm until the car starts moving, proves the opposite of what you’re saying – air is touching 95% of the tire, the track’s touching 5%, only the bit in contact with the track is getting any cooler (but this happens to a part of the tire the camera can’t see while the car’s motionless – as soon as they start moving you can see a cold spot on every single car on the grid, right in the place where the tire was on the ground)


    1. You can also tell in the video that the outer edge does indeed stay hotter longer than the middle of the tire that is in contact with the ground.

      Liked by 1 person

    2. “The bit you mentioned at the start, about the tire staying warm until the car starts moving, proves the opposite of what you’re saying”

      Lmao do you realize that when the car starts moving the contact surface is exposed to huge air flow which cools the tires.


      1. The car starts moving, exposing more of the tire to the track surface. Air is literally a thousand times less effective at heat transfer than asphalt; the only reason engines are air-cooled is they don’t have an alternative (boats do; all marine engines are watercooled because it takes a much smaller heat exchanger)


        1. You talk about common sense and then act like the air moving is somehow different from the track moving? Get your frame of reference straight, man. From the tire’s point of view new cold asphalt is flowing over it at almost the same rate as new cold air (the difference being, air trapped inside the wheel arch will be moving more slowly than clean air.).

          I am not saying, and have never said, that air has no effect. I’m simply saying that DK is right, contact with the track surface is the largest destination of heat generated by the tire.

          @ a drag strip, the left and right tires come into contact with the track surface in a symmetric fashion since there are no corners to affect contact patch. If the airflow is not symmetric then the side being hit will of course be colder. That doesn’t mean that the air is the largest source of cooling, just that it changes the outcome.


          1. Oh right, thats why EVERY SINGLE setup guide on tyre temps has the inner hottest and outter the least hot,with a recommended difference of about 10degrees C across tyre if camber is setup correctly,I have NEVER seen evidence of the outer ever getting hotter than the inner, this is really basic stuff.

            you are grossly underestimating friction causing heat on inners and the air cooling on outter, even when the outer starts touching (mid corner) the major tyre load is STILL on the inside, in other words, the outter never gets THAT hot for it to have to cool much, adn if it is getting too hot, I can gurentee your inners are screwed, id go so far to say a race car with decent camber would be near impossible for the outter to get hotter than the inner.

            depending on tyre pressure,adn if the camber was little enough, the outer MAY momentarily be hotter than the middle, but certainly not the inner.


            1. I don’t even need to hit play on the F1 video to see outside hotter than middle, it’s like that in the preview photo and on approximately every straight…


              1. Do you realise that the hot temperature is shown as colour and not the other way around? Because quite clearly, the colour remains in the inside of the tyre for longer.


    3. A race engineer told me at the drag that due to a cross wind their right side tyres were getting so cold compared to the other side. You’re talking about tyres cooling air, no, the air is being blasted at the tyre and it cools it.


    4. Why do Inuits make a shelter out of snow if surface heat exchange is always more efficient as a temperature change than wind chill? Surely they’d be warmer sitting on a nice warm rug whilst getting blasted by wind, right?

      Heat exchange is only going to be more beneficial if the temperature relativity is wider. So if the track temp is higher than the ambient temp [which often than not, is alot of the time especially at Monza, Italy, at 2pm local time in the early autumn] then the air will do most of the cooling. If the ground was 0c and the wind is 18c, then yes, the wind chill will do nothing compared to physical heat exchange between the tyre and the ground.

      It’s almost like one or two guys have read a thermal dynamics book and are just DESPERATE to use the information in one way or another, when it’s not actually relevant.


  2. That’s the point,the putter portion getts hotter when not in contact with the ground,but as soon as it does,it cools,even tho now it’s generating its own heat.
    Another member suggested they do it this way to stop the tyres over heating in corners,basically bleeding heat away from the I,m, thru the outer.
    That video indeed prooves d.k wrong


  3. I just spoke to a CFD and fluid mechanics expert [they obviously know a lot about air] regarding this issue and confirmed that [almost] everything I’ve said here is correct about air cooling tyres. He also said rolling friction is the single biggest factor as to why we see the inside shoulder still retain heat on the straights and that air will cool the rest of the tyre down along with minimal heat exchange differential from the remaining part of the tyre touching the ground. Which obviously fits the video, since f1 cars run high negative camber thus not all of the tyre is in contact with the track at all times.

    Believe what ever you must but I got the answers I was looking for and I KNOW what is fact and what is fiction.


    1. It seems like most people are talking about heat transfer as if its always in a static state and air is never moving, ya asphalt transfers heat faster statically, but at 200 mph that air flow changes alot on its cooling effect while the asphalt only causes more friction and more heat the faster you go.


      1. At last someone gets it,this was said in the discussion but all the pesponses where based on a static tyre.
        No one gave a response to the ure in motion,because they knew they couldn’t refute it.
        But that’s just how they role,twist reality to suite there argument


    2. Do you mean the guy on reddit who said Kaemer’s assertation was plausible and not really his area of expertise?


      1. But did he blindly agree with him because he didn’t know? In all honesty I think he was just trying to leave Kaemmer with dignity, especially after the comment he made that was “I’d really hope the director of a race sims physics would know more than I do”


    3. The F1 video shows exactly the same thing as iRacing, dumbass.

      Inner shoulder – touching the ground, generating friction: hottest
      Middle – touching the ground, generating less friction: cooler
      Outer shoulder – not touching the ground, generating no friction: hot again


    4. That’s right. The compression and shearing forces on the inner shoulders of the tyres are the major factor contributing to them gaining temperature rather than losing it.

      The oncoming and circular air flows do also cause friction, but for that friction to actually have a major impact over the heat exchange processes, the upper part of the tyre in question should advance at a velocity in excess of 1M and preferably stay there. At F1 top speeds it indeed can attain a significant fraction of the speed of sound, yet not enough for the heat buildup to overcome the heat exchange processes.

      So, it should indeed resemble what the video above shows: the outer shoulders of the tyres cool down much faster than the inner ones. Also, for the heat source they almost exclusively have just the cord and the neighbouring rubber from the mid- and inner parts, which hardly helps to gain much heat to begin with.


    5. I just start typing about how us being teached in school about basic thermodynamics and friction and yes. You asked professionals. Im still agree – people who trying to defend Kaemer are… Are they even end low school?


    1. If 8 is bigger than 2, then how can 2 be called a positive number?

      ^ this makes as much sense as your question.

      DK never said “air doesn’t cool the tires”, he said “most of the cooling is from the track surface”. That could mean 80% of the cooling is from track surface, it could mean 90%, it could mean 99%… it doesn’t mean 100%, because he would have said “all”.


    2. Who suggested air doesn’t cool the tires?

      It’s not as efficient a heat exchanger as asphalt, but it’s the only one available (to cool brakes).

      The fact that brakes can get much hotter than tires is irrelevant. The greater the heat, the more exchanged.


  4. I´ve driven iRacing a bit and certainly the tire-model is shit. I don´t know about the temps, but iRacers gather their fastest laps most time at the end of a race. To the hole tire wear is bullshit. Driving Raceroom, AC, pCars & co. and watching RL-racing, it´s certain, that tire wear effects the lap times far more than lighter weight due to the burning of fuel.


    1. In over 1000 races, my fastest lap has never been that late in a race. In fact, the Skippy is the only car I’ve ever come close, and I’m pretty sure it uses road tires (which barely wear over 20 laps).

      That’s not to say that the tire model is perfect, but what you describe is farther from reality.


    2. Interesting, as I never heard of that story … and you know that tires have heat cycles, don’t you ? if you don’t, don’t even bother talk about the “physics”


  5. The best it of this whole thing is Jake C trying to tell us he’s not the same person as the reddit user. LOL. We can see the post history dude.. Anyway Kaemmers tyre model is munted.


  6. Long story short, this Jake C guy got bashed in the forum by number of logical evidences backing up Dave’s claim then here he’s crying & saying that ” They, those fanboys, bullied me!!!!!! ahhhhhhhhhhhh ”

    I think it’s cute 😉


  7. Literally anyone who says the outside of a tire (that’s not touching the ground) will be hotter than the inside of the tire is a retard or just trolling. If you’d know any mechanics and thermodynamics you would know that the friction between tire and road (also mind, even when going straight there is a tire slip-moment between tire and road, albeit in the region of <1%) makes the inside of the tire (touching the ground) cool down SLOWER than the outside due to the relative velocity of the tires compared to the standing air.

    If you still don't believe me, go your closest racing track with a temperature node, and ask one of the teams if you can measure tire temps, or ask them what the tire temps are. At best, the temps will be evenly spread (+-1 or 2 degrees), however in 9 out of 10 cases you will find that the outside of the tire is cooler than the inside.


    1. I don’t but I don’t need to go to track because you don’t seem to understand the subject.

      It’s not the outside being hotter, it’s the outside being cooled much less efficiently so it stays higher than inside.


      1. To paraphrase what you said “It’s not the outside being hotter, it’s the outside being hotter.”

        Do you even read the shit that you write? Yes, when the car IS STANDING STILL the outside of the tire gets cooled less efficiently, but we are talking about a moving object, where what you say is flat out wrong. Write to any racing team, no matter if its a pro or ameteur team, and they will confirm that when the car comes back to the pit, outside temperatures of the tires will ALWAYS be higher than the inside temperature. You can even Google the topic and find out that you are wrong.


        1. you sound like so pro xD give me that “google” link then if you believe so 😀

          It sounds like you believe in a god of wind and it solves every cooling issues huh ?

          First, it’s a box car and air cooling is even worse than an open wheeler. while the contacted surface evens up between cooling & heating (due to friction) on the surface there’s also carcass heat travels internally. While the air is not much in effect of cooling the “never touching” outside tire struggles to discharge the heat.

          gas vs solid = which one is better conductive ? you much have slept a lot in the science class.


          1. What fucking box car? We are speaking in general and especially about open-wheel cars. You still epically fail to grasp the situation here. Yes, solids in general are better heat conductors than gases. Yes, when the car is standing still what you are saying is right.

            However, in a real life situation, the track temperature will almost always be higher than the air temperature (buy up to 50% in some cases), so it won’t conduct heat from tire to surface very efficiently. On the contrary, when the car is moving, there is so much air flowing around the car and the tires that the lesser heat-conducting efficiency of the gas (air) is negligible and will effectively cooldown the tire to a much greater degree than the surface. Thus, the outside of the tire (which has no connection to the road) will have a much lower temperature faster than the inside of the tire, because in this case, with the tires attached to a moving object, the air effectively is a better heat conductor than the road surface.


            1. Dude … look at the original post and what car he was driving to get that “weird result” he had absolutely crazy camber and that symptom was only happening in the straight where the outside has absolutely zero contact with the ground.

              and all those articles referring when the O/M/I parts of tire making relevant contacts with the surface.

              This farking kid fails reading the context. I should leave now. bye.


      2. You actually have no idea what you are talking about but you think you do. That’s dangerous.

        You are confusing a thermal dynamic properties of a tyre in a static state, and a thermal dynamic properties of a tyre in a moving state and projecting them to be exactly the same. Even though video evidence proves you wrong.


  8. You seem to be aware that thermal exchange happens between the tyre and the track, so If that part of the tyre was NEVER touching the ground dude because of how extreme his cambers were, how would it ever get heat into it in the first place?

    Your logic is flawed.


      1. You said “Dude … look at the original post and what car he was driving to get that “weird result” he had absolutely crazy camber and that symptom was only happening in the straight where the outside has absolutely zero contact with the ground.”

        It is proven in thermal imaging videos that the part of the tyre not touching the ground as much, will be subject to less heat and wear. It’s not rocket science.


        1. it has zero contact in the straigh line, yes. You don’t need to argue with me if you ever bother to read the whole story…

          so you have evidence of the outside don’t touch the surface by watching that freaking F1 video. very nice. well done (clap clap)


  9. This comment section demonstrates how bad our science education is, and more importantly how poorly people are equipped to operate any critical thinking skills.


  10. The *original* question on the iRacing forum was why the outside of the tire was hotter than both the middle and inside once those two had cooled to a steady state at the end of a straight. All the youtube temperature footage shows that after enough straight for the inside and middle to have cooled to a steady state, the outside has cooled as well. This contradicts what Dave Kaemmer stated and the data that was shown.

    Talking about “rates of change” of temperature or rate of heat transfer confuses matters because the rates change; if the inside is initially hotter than the outside, then of course it looses heat faster because rate of heat transfer is proportional to temperature difference with the environment (road/air). That appearance on some video footage was ceased by iRacing defenders as evidence DK was right, when it isn’t.


  11. With respect to Sev, finally, me as amateur simracer has found on PRC topic, where you totally give facts. (I am a common guy who have real life to deal with, not to waste time defend or attack simracing titles trying to find truth in the land of parallel reality of “just words”, BUT who looking for as much realistic simulation as possible). So again, i wish you to pay more attention on this kind of physics stories about iracing and rfactor/isimotor sims.
    I know, that the core theory of driving physics were made when the first computer calculations entered Racing, and many books were written. I have one. But this story, with this screenshot… Its just freaking bomb. Im not a physics guy, buy my knowledge and education can help me understand a lot in physics, and what Kaemer told to us in this… Its freaking sad. I have no words to explain.

    I just have no words to get it.

    Still have no words.


    1. Speaking of level of education, clearly you didn’t learn critical analysis in university.

      I’m not necessarily defending iRacing’s side but when you want to kick back you need to bring up more logical evidence rather than keep shouting “OMG it’s common sense !! everyone knows that guys!! iRacing is lying !! ”

      Sorry but just like you said you clearly had “no words to explain”

      and excuse me ? what the fuck all the bullshit books you read got to do with this matter ?

      Could you give us any citation ? if you received any higher education degree than bachelor you’d know that you should ….


    2. Yes and sadly, not enough people will tell Kaemmer he’s talking out of his ass. Not enough people will or even do realise that iRacing is totally fucked, physically. They have even professional endorsements from real racing drivers, so literally there is no chance to de-throne iracing.

      It’s a sad sad world we live in. They even charge $£$£$£ that you’d only expect from a fucking golf country club but people still accept it and pay for it when it’s STILL substandard.


      1. It’s sad that you seem to have no brain and no logical back up of what you’re saying.

        On what base iRacing is fucked as of today and how did you determine that ?


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