Essay alert, I just spent a few hours on this comment.. :S At 13:15 where you mention static friction, you're taking an incorrect path (hohoho). Making a car change direction on a straight does not work the way you describe. You don't need to overcome a static friction value before the car starts to turn. If your car is parked on the banking and you want to push it down sideways, yes, then you have the sofa example. A rolling tire that is part of a car that is driving around, behaves completely differently. Imagine you're coasting down a flat straight in neutral. There are effectively no tire forces acting on the car. Drag will slow you down, but there is no tire grip / friction or anything occurring that is significant. For the next bit, I'm describing what happens in super slow motion. Imagine turning the wheel very slightly but very fast, just 10 degrees of steering angle in the blink of an eye. The front tires are now at an angle versus where the car is pointing. The car itself is still going straight, it hasn't had time to react. This angle difference between the front tires and the car is what is called the slip angle. Slip angle makes a tire generate cornering forces, and we just went from 0 to maybe 0.5 degrees on the tires. This will create a slight cornering force on the front tires, maybe just 100 pounds. Meanwhile, the car is still going straight, hasn't had time to catch up. The rear tires are still pointing straight ahead too, so they're at zero slip angle. And grip needs slip angle so we have none at the rear! We have front tires generating grip, and rear tires not generating grip. This sounds weird, but at zero slip angle, a block of ice produces the same cornering grip as a rubber tire. And what happens when front tires grip and rears are blocks of ice? The car starts to rotate. We're still in super slomo, this isn't dramatic Tokyo Drift. As the whole car starts to rotate from the front tires pulling on the car, the car is no longer pointing towards where it is traveling. The car, and with it the rear tires, are at a slight slip angle. And unlike blocks of ice, rear tires generate cornering grip when they are at a slip angle. Maybe just 50 pounds. Now the car is being pulled sideways with 100 pounds from the front tires and 50 pounds from the rear tires. It will gently start to change lanes and keep changing direction very slowly. There is no static force that needs to be overcome before the car changes lanes. It is extremely analog and accurate. Doing it gently also doesn't heat up the tires any more than just the heat generated by the rolling of the tire. A banked corner is a bit different. For each corner radius and banking angle, there will be a speed where you can let go of the wheel and the car will follow the track perfectly, like you correctly described talking about centrifugal force, gravity and normal force equaling each other out. Still, the same applies. Apply a tiny bit of steering and the car will go up or down the banking, with the same tiny 100 pound front and 50 pound rear tire forces, that add no real heat to the tire. So what DOES create heat? First just the tires rolling with the weight of the car and downforce on it will warm them up. But in the turns, it's those slip angles that scrape the tire over the road at an angle that really cause heat to be generated. And while a tiny slip angle is enough to change lanes gently, maximum G force turns will create larger slip angles. Heat will also be generated faster if you have the same slip angle at a higher tire load, i.e. in grip limited banked turns. Slip angle and tire load are bad for heating. Reducing tire load can't really be done other than going slower. You can do some setup tricks with weight jackers or whatever is available to the car, but at some point the outside front tire is just having to deal with it. Reducing slip angle can be very effective. You might get 90% the grip at 60% the slip angle. So getting a good feel for how far to turn the wheel, feeling the diminishing returns of the last bit of steering, can help a huge amount. And, the less time you spend cornering hard, the less heat. This might be the answer to why "anti arc" as you call it, reduces heating. The "arc" line probably means you're cornering hard, maybe a second or so more per lap than the "anti arc" line. Maybe this isn't the entire story but it seems like a plausible explanation. It certainly isn't your 'static friction is higher on the banking' argument. :-) I do like people trying to use physics and science, it just so often isn't quite right and people think they learned something when you, without intention, just told them 1+1=3.
This will prob take a while for me to fully dig into, and they new ideas that you brought up I believe are great points, but I do have a counterargument for the static friction point! I do believe a tire does experience static friction because assuming a straight unbanked track, each point of rubber on the tire is only in contact with 1 point of the asphalt before being lifted up off the surface through the wheel rolling. For a slip angle to happen on a tire, that point of rubber would over time have to travel along the surface. I found this video which I think is relevant: th-cam.com/video/J0PVm4XTGeY/w-d-xo.html
@@billbenedict4664 but when you’re driving a car on a race track and taking a corner my argument is you go from this straight line without slip into a slip which would require overcoming the static friction force between the rubber and the surface to accelerate into the slip angle. Even if it’s not static friction (which I’ve looked around and still 100% believe it is) the force required to induce the slip is still proportional to the normal force and even though the speed is squared, the difference between a fast and slow entry is a factor of maybe 1.1-1.2 while the difference in normal force between a straight and corner is 2-3. And while this is applied over time my argument is that it is more efficient to save tires the later way. I’m not saying you don’t save tires by going slower, my whole point is you don’t NEED to save tires by going slower
@@DJYeeJay Sorry but no. In sim physics engines, which do a decent job of mimicking real life, there are no static friction forces that you have to overcome before the car does anything. I have access to the source code, I have worked on sim physics for so long, I fear I even understand a small fraction of it by now.. And the reason this isn't a thing in simulators is because it isn't a thing in reality either. The rolling tire generates grip from slip angle and or slip ratio (braking / acceleration). Both these slips are effectively zero when the car is just coasting, and it only takes 2 fingers on a non power assisted steering wheel to generate enough slip angle for the car to start turning. Just like it only takes the slightest press on a non power assisted brake pedal to ever so slightly start slowing down. No force has to be overcome before the car starts to turn or decelerate, other than the friction in the braking system and steering rack. If there would be this great static friction force to overcome, how would you explain that even without powersteering, once you're going 30mph, slight steering takes very little effort? What overcomes this big friction force if it doesn't take the driver nearly any work? I don't know if iRacing has such detailed telemetry, but in sims that do, you can see all the forces on the tire. The normal force (tire load), lateral force (cornering) and longitudinal force (acceleration / braking). A tire can turn tire load into lateral or longitudinal force, based on the driver inputs, as he/she makes the car turn, brake or accelerate, or slide off the road. That's basically it. Of course physics are very tricky to intuitively understand and it is completely understandable that you took a wrong turn here. If I would reply to all real or sim drivers who misunderstand something about vehicle dynamics, there wouldn't be enough time in the day. And I certainly don't understand it all either. However, you're touching on such a relatively basic aspect that I am almost certain you're completely false in this case. Sounds silly but do you have maybe a LEGO car that has steering? Push it sideways while it is just parked is your 'sofa example' .. But now drive it and steer it, it will smoothly (well.. it is LEGO so not that smoothly) drive straight and gently turn as you steer it a bit. The forces you're thinking about don't apply to a rolling tire. I don't want to sound like an ass, I'm just dropping something I'm 98% confident are basic vehicle dynamics facts. 🙂
@@NielsHeusinkveld thank you for the info I really do understand what you’re saying and can understand your point about steering becoming easier as velocity increases. I cannot understand why a rolling tire would have different properties to a tire that is not rolling. From the reference point of a point on the rubber or the track, a lateral force in my head should behave the same as in both cases the rubber and track are fixed to each other. Does the momentum of the car change this? Either way though, regardless how it’s classified, it seems lateral force to rotate the car should be proportional to the normal force is that correct? I guess my whole point of this exercise is to get people to understand rotating the car under the least amount normal force, and there are multiple ways to do that and not just overslowing the car
sounds like you are talking about "rotating" the car before the banking when you say "turn", in road racing parlance. Initiating the rotation before the banking.... makes a ton of sense. thanks for sharing this. Super helpful.
Videos like these are why you're the GOAT. If anyone needs to understand the tantrums people throw during the race, I'm happy to dust off my psych degree.
There's a really good post on the iRacing forum under the API and Developers section on how to set up McLaren ATLAS to analysis your ibt telemetry (somewhat redundant if you use VRS), where you can see tyre surface temps for your entire stint, directly related to wear in the model, so you can run different lines and see what's best. Would love to see what overlaid on your farmer's guides but the data is only in the disk telemetry not the live feed that the overlays use.
Just to inform, not to scare, I'm watching this for the second time now looking for gaps, as I do think there are some. But I do appreciate the idea of using science to explain something. However, with the use of science / physics, comes the risk of being shouted at by a guy who ones made a spreadsheet. Can you maybe do a followup, doing laps one way and the other? Just to see what you mean exactly and I can maybe replicate it myself.
Watching this back I think I honestly could’ve cut out everything about centrifugal force. It kinda explains why going slow into a corner saves tires but that’s already intuitive
There's a few dodgy assumptions and definitions in there, but your final answer about a shallower entry is right, just not because of the banking... a shallower entry means you have to enter the corner with less speed, and the v^2 component matters a lot. The less speed you have when you turn the wheel, the less force you're putting through the tires. Banking exacerbates the effect, sure. But because of the banking you need less slip angle on the wheel/tires too. Typical tire-killers are too much speed on entry and keeping the steering wheel turned hard on exit. A tire-killer driver could still eat up tires on that shallower entry if they don't slow down enough and they try to turn the wheel more to compensate.
I run a bunch of long races 150-200 laps with no tires allowed and I can confirm that letting off early and rolling the corner does not save tires as well as you think. It’s more about braking in a straight line and turning the wheel AFTER you have the car slowed down.
You have that backward. True Americans don't know the metric system. Smart Americans know it's the best measuring system. Also, I wonder how many Americans are gonna get triggered at you for calling it a "NASCAR."
Exactly. Americans will always rebutt with "Comeback to me when you put a flag on the Moon", completely forgetting the fact that NASA engineers would've used the metric system to get that flag there.
Essay alert, I just spent a few hours on this comment.. :S At 13:15 where you mention static friction, you're taking an incorrect path (hohoho).
Making a car change direction on a straight does not work the way you describe. You don't need to overcome a static friction value before the car starts to turn. If your car is parked on the banking and you want to push it down sideways, yes, then you have the sofa example. A rolling tire that is part of a car that is driving around, behaves completely differently.
Imagine you're coasting down a flat straight in neutral. There are effectively no tire forces acting on the car. Drag will slow you down, but there is no tire grip / friction or anything occurring that is significant. For the next bit, I'm describing what happens in super slow motion.
Imagine turning the wheel very slightly but very fast, just 10 degrees of steering angle in the blink of an eye. The front tires are now at an angle versus where the car is pointing. The car itself is still going straight, it hasn't had time to react. This angle difference between the front tires and the car is what is called the slip angle. Slip angle makes a tire generate cornering forces, and we just went from 0 to maybe 0.5 degrees on the tires. This will create a slight cornering force on the front tires, maybe just 100 pounds.
Meanwhile, the car is still going straight, hasn't had time to catch up. The rear tires are still pointing straight ahead too, so they're at zero slip angle. And grip needs slip angle so we have none at the rear! We have front tires generating grip, and rear tires not generating grip. This sounds weird, but at zero slip angle, a block of ice produces the same cornering grip as a rubber tire. And what happens when front tires grip and rears are blocks of ice? The car starts to rotate. We're still in super slomo, this isn't dramatic Tokyo Drift.
As the whole car starts to rotate from the front tires pulling on the car, the car is no longer pointing towards where it is traveling. The car, and with it the rear tires, are at a slight slip angle. And unlike blocks of ice, rear tires generate cornering grip when they are at a slip angle. Maybe just 50 pounds.
Now the car is being pulled sideways with 100 pounds from the front tires and 50 pounds from the rear tires. It will gently start to change lanes and keep changing direction very slowly. There is no static force that needs to be overcome before the car changes lanes. It is extremely analog and accurate. Doing it gently also doesn't heat up the tires any more than just the heat generated by the rolling of the tire.
A banked corner is a bit different. For each corner radius and banking angle, there will be a speed where you can let go of the wheel and the car will follow the track perfectly, like you correctly described talking about centrifugal force, gravity and normal force equaling each other out. Still, the same applies. Apply a tiny bit of steering and the car will go up or down the banking, with the same tiny 100 pound front and 50 pound rear tire forces, that add no real heat to the tire.
So what DOES create heat? First just the tires rolling with the weight of the car and downforce on it will warm them up. But in the turns, it's those slip angles that scrape the tire over the road at an angle that really cause heat to be generated. And while a tiny slip angle is enough to change lanes gently, maximum G force turns will create larger slip angles. Heat will also be generated faster if you have the same slip angle at a higher tire load, i.e. in grip limited banked turns.
Slip angle and tire load are bad for heating. Reducing tire load can't really be done other than going slower. You can do some setup tricks with weight jackers or whatever is available to the car, but at some point the outside front tire is just having to deal with it. Reducing slip angle can be very effective. You might get 90% the grip at 60% the slip angle. So getting a good feel for how far to turn the wheel, feeling the diminishing returns of the last bit of steering, can help a huge amount.
And, the less time you spend cornering hard, the less heat. This might be the answer to why "anti arc" as you call it, reduces heating. The "arc" line probably means you're cornering hard, maybe a second or so more per lap than the "anti arc" line. Maybe this isn't the entire story but it seems like a plausible explanation. It certainly isn't your 'static friction is higher on the banking' argument. :-)
I do like people trying to use physics and science, it just so often isn't quite right and people think they learned something when you, without intention, just told them 1+1=3.
This will prob take a while for me to fully dig into, and they new ideas that you brought up I believe are great points, but I do have a counterargument for the static friction point! I do believe a tire does experience static friction because assuming a straight unbanked track, each point of rubber on the tire is only in contact with 1 point of the asphalt before being lifted up off the surface through the wheel rolling. For a slip angle to happen on a tire, that point of rubber would over time have to travel along the surface. I found this video which I think is relevant: th-cam.com/video/J0PVm4XTGeY/w-d-xo.html
@@DJYeeJay That video applies to a tire rolling straight. A tire cornering almost always some slip angle and is sliding.
@@billbenedict4664 but when you’re driving a car on a race track and taking a corner my argument is you go from this straight line without slip into a slip which would require overcoming the static friction force between the rubber and the surface to accelerate into the slip angle. Even if it’s not static friction (which I’ve looked around and still 100% believe it is) the force required to induce the slip is still proportional to the normal force and even though the speed is squared, the difference between a fast and slow entry is a factor of maybe 1.1-1.2 while the difference in normal force between a straight and corner is 2-3. And while this is applied over time my argument is that it is more efficient to save tires the later way. I’m not saying you don’t save tires by going slower, my whole point is you don’t NEED to save tires by going slower
@@DJYeeJay Sorry but no. In sim physics engines, which do a decent job of mimicking real life, there are no static friction forces that you have to overcome before the car does anything. I have access to the source code, I have worked on sim physics for so long, I fear I even understand a small fraction of it by now.. And the reason this isn't a thing in simulators is because it isn't a thing in reality either. The rolling tire generates grip from slip angle and or slip ratio (braking / acceleration). Both these slips are effectively zero when the car is just coasting, and it only takes 2 fingers on a non power assisted steering wheel to generate enough slip angle for the car to start turning. Just like it only takes the slightest press on a non power assisted brake pedal to ever so slightly start slowing down. No force has to be overcome before the car starts to turn or decelerate, other than the friction in the braking system and steering rack.
If there would be this great static friction force to overcome, how would you explain that even without powersteering, once you're going 30mph, slight steering takes very little effort? What overcomes this big friction force if it doesn't take the driver nearly any work?
I don't know if iRacing has such detailed telemetry, but in sims that do, you can see all the forces on the tire. The normal force (tire load), lateral force (cornering) and longitudinal force (acceleration / braking). A tire can turn tire load into lateral or longitudinal force, based on the driver inputs, as he/she makes the car turn, brake or accelerate, or slide off the road. That's basically it.
Of course physics are very tricky to intuitively understand and it is completely understandable that you took a wrong turn here. If I would reply to all real or sim drivers who misunderstand something about vehicle dynamics, there wouldn't be enough time in the day. And I certainly don't understand it all either. However, you're touching on such a relatively basic aspect that I am almost certain you're completely false in this case.
Sounds silly but do you have maybe a LEGO car that has steering? Push it sideways while it is just parked is your 'sofa example' .. But now drive it and steer it, it will smoothly (well.. it is LEGO so not that smoothly) drive straight and gently turn as you steer it a bit. The forces you're thinking about don't apply to a rolling tire. I don't want to sound like an ass, I'm just dropping something I'm 98% confident are basic vehicle dynamics facts. 🙂
@@NielsHeusinkveld thank you for the info I really do understand what you’re saying and can understand your point about steering becoming easier as velocity increases. I cannot understand why a rolling tire would have different properties to a tire that is not rolling. From the reference point of a point on the rubber or the track, a lateral force in my head should behave the same as in both cases the rubber and track are fixed to each other. Does the momentum of the car change this? Either way though, regardless how it’s classified, it seems lateral force to rotate the car should be proportional to the normal force is that correct? I guess my whole point of this exercise is to get people to understand rotating the car under the least amount normal force, and there are multiple ways to do that and not just overslowing the car
These guys with engineering degrees I tell ya.. they're taking over F1 and now they're taking over iRacing
As a mechanical engineer, i can confirm I ’m too lazy to check his work 😂
🤣🤣🤣
Typical engineer
@itsgabeplays Same brother 😂
*proceeds to use his data anyway, because why not?
@@CronySlaystation84 shhhh I’ve only had one bridge fall
Fellow Engineer & Iracing enthusiast, fantastic work
sounds like you are talking about "rotating" the car before the banking when you say "turn", in road racing parlance. Initiating the rotation before the banking.... makes a ton of sense. thanks for sharing this. Super helpful.
I don't think you need an engineering degree to understand why I'm hard on tires. I'm pretty sure the tire smoke explains it. 😅
Would have probably gotten better grades in my physics classes if they related it all to racing
you can is the great part! if you understand the underlying concepts you can build it out to figure out how cars work :)
Holy crap this made so much sense I had a eureka moment and I’ve been tuning race cars suspensions (road racing) for 30 years
Videos like these are why you're the GOAT. If anyone needs to understand the tantrums people throw during the race, I'm happy to dust off my psych degree.
Love the videos DJ. I watch religiously… but this right here. I can’t do it… not on my only break during work. I’ll come back later 😂
I Was not expecting Justin to be lightning McQueen today 🤣
Holy, I just realized your almost to 40k! Congrats!
Thanks for the great video as always.
Kansas in the truck league tonight.
I'll try my best at implementing this.
My statics and dynamics lecturer would have a heart attack seeing this
But the assumptions would make you a fine engineer
There’s enough estimations to make everything useless 🤣 luckily this is just for visualizing
I didn’t need this to tell me I’m bad at tire saving, my tires lasting a few laps tells me 😂
Engineer? Im subscribing. What I know is it all depends on the car setup.
Saw this on my front page of YT and instantly sent this to my buddy who sucks at tire wear😂
There's a really good post on the iRacing forum under the API and Developers section on how to set up McLaren ATLAS to analysis your ibt telemetry (somewhat redundant if you use VRS), where you can see tyre surface temps for your entire stint, directly related to wear in the model, so you can run different lines and see what's best. Would love to see what overlaid on your farmer's guides but the data is only in the disk telemetry not the live feed that the overlays use.
I was trying together look into that but I couldn’t find a place to download atlas, where did you find it?
@@thatoneguy4448 it's all referenced from the iRacing post on their forum.
Visual learner here...thank you!!
Fantastic video!
Of course he uploads this right after my midterm💀
I love this video but I didn't need all this to tell me I suck at tire saving, I know after about 5 laps. lol good video tho and I love the costume!
Ah, yes. I have definitely heard all these words before
As someone with an engineering degree, I am all about this!
Looking like the default NPC in create your driver.
Free body diagrams hit home for me. My AP physics C class is on the forces unit 😂
Shh you're not supposed to tell people, I've been using this knowledge to my advantage forever
Think about all the basic questions you hear during a race. You don't have to worry about all the drivers learning this.
The title got me
You did not need to go through making a video to tell me this....
I know Im bad at it lol.
Just to inform, not to scare, I'm watching this for the second time now looking for gaps, as I do think there are some. But I do appreciate the idea of using science to explain something. However, with the use of science / physics, comes the risk of being shouted at by a guy who ones made a spreadsheet. Can you maybe do a followup, doing laps one way and the other? Just to see what you mean exactly and I can maybe replicate it myself.
Watching this back I think I honestly could’ve cut out everything about centrifugal force. It kinda explains why going slow into a corner saves tires but that’s already intuitive
Terrifying 😱
Man why'd you have to put that picture of Larson spinning lmao
10:13 picture :(
I litterally bought that same costume like a week ago
As an English Major at an Engineering University I believe you are correct and do not know how to do the math to check your work.
i can confirm that i am TERRIBLE at tire saving, i finished a street stock race last night with only 17% tread left on the right front 😭
You're turning the wheel entirely too much!
hey could you potentially get a new link for the chat gpt track for nr2003
uhh i can try to track it down idk if that track is still on my pc i guess it should be
okay
There's a few dodgy assumptions and definitions in there, but your final answer about a shallower entry is right, just not because of the banking... a shallower entry means you have to enter the corner with less speed, and the v^2 component matters a lot. The less speed you have when you turn the wheel, the less force you're putting through the tires. Banking exacerbates the effect, sure. But because of the banking you need less slip angle on the wheel/tires too. Typical tire-killers are too much speed on entry and keeping the steering wheel turned hard on exit.
A tire-killer driver could still eat up tires on that shallower entry if they don't slow down enough and they try to turn the wheel more to compensate.
This is cool and all. But how do I save tires?
TLDR: Turn steering wheel before banking transition, and try to even out oversteer and understeer
@@DJYeeJay I love you.
You don't need to prove it, I just had almost a second of falloff in Legends...
You don't have to flex on me with that title. :(
nice degree, mind dropping me a link so I can become an engineer as well bud?
just because you are an engineer doesn't mean you are smart, I've known a lot of dumb engineers
lets goooo 15s ago we here EARLY
Common sense let of early to save tires and roll thru the corners
I run a bunch of long races 150-200 laps with no tires allowed and I can confirm that letting off early and rolling the corner does not save tires as well as you think. It’s more about braking in a straight line and turning the wheel AFTER you have the car slowed down.
😵💫
You have that backward. True Americans don't know the metric system. Smart Americans know it's the best measuring system. Also, I wonder how many Americans are gonna get triggered at you for calling it a "NASCAR."
Exactly. Americans will always rebutt with "Comeback to me when you put a flag on the Moon", completely forgetting the fact that NASA engineers would've used the metric system to get that flag there.
@Eis_ lol, as an American, I've never heard anyone say this, but if I ever do, I'll definitely think of this comment now.
@@Eis_yeah man bc the measurement system is what we’re concerned about there lmao. Low iq comment
Says the guy with an engineering degree
WE HERE EARLY
What?