iracing.com

[Jav]

I really don't get people's complaint about the tire wear... For the distances we run on any of our races, even the 2.4 ones your tires shouldn't wear down to the cords. Off course there's Pirelli and F1 with the silly degradation and wear, but other than that tires in real life do last a lot! You can definitely feel the tire degradation on long races if you push from the start, if you take care of your tires from the start you'll still have tires left at the end of a long stint.
It almost looks as if some people want to get the silly tire wear from GT5 into iRacing!
Talking about the road side here, I'm completely ignorant to the oval side of things!

 

[Wilbur]

I really don't get people's complaint about the tire wear... For the distances we run on any of our races, even the 2.4 ones your tires shouldn't wear down to the cords. Off course there's Pirelli and F1 with the silly degradation and wear, but other than that tires in real life do last a lot! You can definitely feel the tire degradation on long races if you push from the start, if you take care of your tires from the start you'll still have tires left at the end of a long stint.
It almost looks as if some people want to get the silly tire wear from GT5 into iRacing!
Talking about the road side here, I'm completely ignorant to the oval side of things!

I totally agree with that and seems like it holds true.

Oval side at some tracks has to where you can run wide open in trucks for first 2 laps then slowly have to use less throttle which seems normal to some degree as tires fall off but they don't go from perfect to crap in a normal race, just a lot slicker is all. New tires are always better but I don't think they should be worn out sliding if you can go wide open for first laps by lap 6 if you don't back down some though.

 

[Roush_fan_99]

Wait a min, I remembered something else now that you say that gogatrs, when you bump up the pressure, it was reasonably looser for the first couple laps then it came in fairly fast didn't it?
Contact patch is how much of the tire actually touches the pavement, so a flat tire has the largest and an over inflated tire has the most curvature and therefore the least. And more contact means more friction/grip as shown with wide tires at a drag strip.
However, a friend of mine who moved up from QM before I did, said that with the larger kids (because of drastic increases in body roll), we had to leave the suspension (most people tried going from 120 up to 200 gradually in spring rates) and lower the pressure from what was typically 20-30 PSI down to about 10-12 and he said it would start with a decent amount of grip and stay more consistent than the stiffer car because the stiffer car slid more. Obviously burnouts are just sliding tires create lots of heat. I know for a fact that the friction of the tire sliding sideways and/or spinouts cause lots of heat and the car would just got tighter and tighter until it eventually start biking. So my point is that the car sliding on over inflated tires ends up creating a lot more friction/heat and what the car does with it depends on the car and tire compounds. Some compounds get really sticky and others just begin to melt. That's why QM would always start to bike ( hilarious moments). And others got really loose. And somehow tire buildup could be tacked on but I can't really explain that other than how it builds up and it's effect on cold restarts.

P.S. - Jav, I'm not arguing for of against the tire model any more, I'm just talking out conceptual physics and examples and seeing if it makes sense to others to apply to the model....

 

[livemusic]

Did two races with the McLaren at the 24 Heures du Fun yesterday, it's pretty fun, especially since you don't worry about SR. In the first race I went without qualifying, started around 20th and was making my way up pretty nicely, think I was 3rd in my class. But then another McLaren went off the track, I didn't see it coming back and ended up hitting it. It seems you get a free repair on these races so I went back to it and finished 7th overall, 4th place within the McLarens. Oh, and I also went too low on fuel so I had to stop for a splash of gas a couple of laps before the end of the race.

My second race was better, I qualified for it and started in 2nd on my class. Got the lead at the start, then lost it after missing a turn, went down to fourth but I managed to get the lead back at the last lap. It was pretty exciting.

It's pretty fun having 5 different cars on the grid, though it got pretty heavy on my GPU. In the esses my framerate would drop to below 50fps. Having 60 cars grid didn't help either.

 

[superbike81]

I really don't get people's complaint about the tire wear... For the distances we run on any of our races, even the 2.4 ones your tires shouldn't wear down to the cords. Off course there's Pirelli and F1 with the silly degradation and wear, but other than that tires in real life do last a lot! You can definitely feel the tire degradation on long races if you push from the start, if you take care of your tires from the start you'll still have tires left at the end of a long stint.
It almost looks as if some people want to get the silly tire wear from GT5 into iRacing!
Talking about the road side here, I'm completely ignorant to the oval side of things!

Let's look at it from the real world perspective. While each car is a little different, typically GT cars in ALMS or European LeMans will stop for fuel about every 45-50 minutes and tires will last two stints. But by the end of each stint you will see significantly slower laps even though they are lighter. Our problem isn't the distance, it's true that we should be able to go a full Grand-Am or Proto/GT race in iRacing without changing tires, but there is virtually no falloff after the first 10 laps, and everyone sets their fast lap on lap 2 (which is the cold tires issue). In the McLaren for example, you get significant falloff in grip during the first 5-6 laps, but after that, you can pretty much run the exact same line, exact same braking points, turn-in points, etc, etc, without having to worry. So yes, we do have tire wear in iRacing, for the first five laps, after that, it's like driving on never ending tires. For iRacing, it's all about tire temp, not wear, you stop in the pits and cool down the tires and you'll come back out running the same lap times you were in lap 5.

Also, tire conservation plays no role beyond the first 5 laps in road racing and the first 20 laps in oval racing. Once you get beyond that, you can abuse the hell out of the tires and get very little or no punishment in lap times.

 

[superbike81]

Wait a min, I remembered something else now that you say that gogatrs, when you bump up the pressure, it was reasonably looser for the first couple laps then it came in fairly fast didn't it?
Contact patch is how much of the tire actually touches the pavement, so a flat tire has the largest and an over inflated tire has the most curvature and therefore the least. And more contact means more friction/grip as shown with wide tires at a drag strip.
However, a friend of mine who moved up from QM before I did, said that with the larger kids (because of drastic increases in body roll), we had to leave the suspension (most people tried going from 120 up to 200 gradually in spring rates) and lower the pressure from what was typically 20-30 PSI down to about 10-12 and he said it would start with a decent amount of grip and stay more consistent than the stiffer car because the stiffer car slid more. Obviously burnouts are just sliding tires create lots of heat. I know for a fact that the friction of the tire sliding sideways and/or spinouts cause lots of heat and the car would just got tighter and tighter until it eventually start biking. So my point is that the car sliding on over inflated tires ends up creating a lot more friction/heat and what the car does with it depends on the car and tire compounds. Some compounds get really sticky and others just begin to melt. That's why QM would always start to bike ( hilarious moments). And others got really loose. And somehow tire buildup could be tacked on but I can't really explain that other than how it builds up and it's effect on cold restarts.

P.S. - Jav, I'm not arguing for of against the tire model any more, I'm just talking out conceptual physics and examples and seeing if it makes sense to others to apply to the model....

Lower tire pressures will give you more contact patch but it sacrifices lateral stability due to more sidewall flex.

I like these kind of discussions Wish we could talk about this stuff more often.

But the fact remains, the tire behavior in iRacing (and many other sims) is screwed up. The iRacing staff has acknowledged that they don't behave correctly and are working to fix it.

 

[Wilbur]

Lower tire pressures will give you more contact patch but it sacrifices lateral stability due to more sidewall flex.

I like these kind of discussions Wish we could talk about this stuff more often.

But the fact remains, the tire behavior in iRacing (and many other sims) is screwed up. The iRacing staff has acknowledged that they don't behave correctly and are working to fix it.

I wish someone could teach me about car setup and what things do in normal terms as yes I know some Iracing stuff is simple but it doesn't fit in my brain correctly for some reason.

 

[superbike81]

I know enough about setting up a car to do it myself, however I don't do it in iRacing. I barely have enough time to fit in a couple races a week with family, work, and school obligations. So downloading a setup and then normally dialing in a little more understeer is all I ever really do. I'm sure I could be a few tenths faster if I spent hours setting up the cars, but I just don't have the time.

If you really want to learn about setting up a race car and getting faster in general, start reading some books about racing and driving techniques. If you don't want to do that (which is completely understandable) just set aside a few hours for iRacing, go into the garage screen, read each setup parameter and make small adjustments in ONE PARAMETER AT A TIME. This is important because you want to know what a specific adjustment does to your car. Setups aren't universally liked by everyone. "Aliens" will set up their cars very loose, almost to the point of being undriveable in my opinion, but they love it. If one of those guys drove a car I setup they would say it's got so much understeer that it's undriveable.

 

[Wilbur]

I don't really have the patience for all that but I have tried. It's like uh what...and I just need to learn more about tires, in race adjustments or small things I can do. I prefer to run a looser car than tight because I will try to over drive a tight car and end up burning the tires up or taking a wall down.

 

[carfetish]

In the McLaren for example, you get significant falloff in grip during the first 5-6 laps, but after that, you can pretty much run the exact same line, exact same braking points, turn-in points, etc, etc, without having to worry. So yes, we do have tire wear in iRacing, for the first five laps, after that, it's like driving on never ending tires. For iRacing, it's all about tire temp, not wear, you stop in the pits and cool down the tires and you'll come back out running the same lap times you were in lap 5.

Tire wear and tire degradation is not the same thing.

 

[Kamuifanboy]

I'm not trying to attack anyone, just contributing to the conversation.

On my go kart, we ALWAYS step up the pressures for shorter races and qualifying or wet/cold track. That way the temperature comes up faster.
And vice versa.
And you can notice the temperature change quite easily on the go kart.
And then you can feel it go away again when the tires start to get too hot.

The theory is that the higher pressure stretches out the tire more to create a larger contact patch. A lower pressure will decrease the size of the contact patch.

Obviously that's just the go karts, which could behave differently than real cars. But that's the general idea.

Yep yep. What you are saying is true. Lower tire pressures does not always mean more contact patch as well guys. It means a tire that is flat rather than slightly rounded. We must remember that generally every car runs with at least 1 degree of negative camber. This becomes even more negative when driving at speed due to downforce. Again I'm no physics major but in my mind, a rounder tire will have more contact patch than a flat tire with the added camber in place.

Let's keep this sort of discussion going. It is really interesting to hear what different people have to say on the topic

 

[gogatrs]

Yep yep. What you are saying is true. Lower tire pressures does not always mean more contact patch as well guys. It means a tire that is flat rather than slightly rounded. We must remember that generally every car runs with at least 1 degree of negative camber. This becomes even more negative when driving at speed due to downforce. Again I'm no physics major but in my mind, a rounder tire will have more contact patch than a flat tire with the added camber in place.

Let's keep this sort of discussion going. It is really interesting to hear what different people have to say on the topic

Ah, forgot about camber. But remember, you adjust camber so that when you come into a corner, you have the biggest contact patch possible. I remember an excellent article on all this somewhere but can't seem to find it.

 

[Patrocles]

How is everyone surviving Week 13?

I have managed to avoid most of the carnage and gain about +0.2 SR. I have had a few off tracks (my SRF brakes seem to be very sensitive and easily lockup? ).

 

[superbike81]

Ah, forgot about camber. But remember, you adjust camber so that when you come into a corner, you have the biggest contact patch possible. I remember an excellent article on all this somewhere but can't seem to find it.

Just thinking out loud here.....

Wouldn't you want less contact patch while not cornering to decrease rolling resistance? So you put in a little more air pressure and adjust the camber where you get the most contact under cornering but the least amount of rolling resistance in the straightaways and corner exits? Of course it's all a very careful balancing act when it comes to setups.

 

[Zathra5_]

Just thinking out loud here.....

Wouldn't you want less contact patch while not cornering to decrease rolling resistance? So you put in a little more air pressure and adjust the camber where you get the most contact under cornering but the least amount of rolling resistance in the straightaways and corner exits? Of course it's all a very careful balancing act when it comes to setups.

Less contact on straights will also give you less grip when braking (or accelerating) in a straight line.

 

[superbike81]

Yeah, like I said, delicate balance.

 

[Matty]

I've gotten up to Oval D 2.97 from 2.72

Also really looking forward to the next 24 hueres du fun race I do

 

[Tyrgaus]

Keep the discussion going ^^ love it!
Ordered CSP V2 yesterday, and its already half way. Cant wait!!

 

[Jav]

I know enough about setting up a car to do it myself, however I don't do it in iRacing. I barely have enough time to fit in a couple races a week with family, work, and school obligations. So downloading a setup and then normally dialing in a little more understeer is all I ever really do. I'm sure I could be a few tenths faster if I spent hours setting up the cars, but I just don't have the time.

If you really want to learn about setting up a race car and getting faster in general, start reading some books about racing and driving techniques. If you don't want to do that (which is completely understandable) just set aside a few hours for iRacing, go into the garage screen, read each setup parameter and make small adjustments in ONE PARAMETER AT A TIME. This is important because you want to know what a specific adjustment does to your car. Setups aren't universally liked by everyone. "Aliens" will set up their cars very loose, almost to the point of being undriveable in my opinion, but they love it. If one of those guys drove a car I setup they would say it's got so much understeer that it's undriveable.

Tire wear and tire degradation is not the same thing.

Carfetish's answer tells a lot about it. And like I mentioned earlier, how you take care of your tires will determine how good of a tire you'll have at the end of a stint. Try the Ford GT on a 2hr race without changing tires and I bet your opinion will change!

 

[gogatrs]

Tire wear and tire degradation is not the same thing.

Didn't see this until Jav posted it.

Not questioning you, but what do you mean?
What's the difference? I've always thought they were the same.

 

[Matty]

Wear refers as too how much tyre is left whereas degradation refers to the rate of wear or fragmentation of it. (Not sure which, if any)

 

[spooble]

Ok. Who keeps breaking the iRacing Forums?? I got my Arduino UNO and display/led boards today, and I can't even get back to the threads on programming them.

 

[Jav]

I think Roush has an allergy and keeps sneeze braking them!! Damnit!!

 

[spooble]

On a lighter note. I ran the Fun race last night at 10:15. It was my first race in the Corvette and first race at Spa. The start was a little bumpy. I made it through eau rouge ok, then chaos on the long straight. I was weaving through the debris field, but a car slid in front of me and I was toast. Sat for almost 4 minutes waiting for the tow, then got black flagged for speeding out of the pits! I kept with it, though. Came back in, served my penalty, and went on the attack. Actually had some good racing during the next 17 laps. Fought my way back to 3rd (4th overall).

 

[Matty]

Had a great fun race there. 24 Heures. Started sencond last from 37 and came 9th in a Caddy 1st in class. Hit a 2:25.9xx as well.

 

[Kevin01SH]

From what i understand with camber (and perhaps i have it wrong, but i want to learn), you would typically want more camber on courses with long sweeping turns to give you the most traction as the car is continually leaning around the bend. But the more camber you use, the longer your braking distance and less traction accelerating out of a tight corner.

 

[Kamuifanboy]

From what i understand with camber (and perhaps i have it wrong, but i want to learn), you would typically want more camber on courses with long sweeping turns to give you the most traction as the car is continually leaning around the bend. But the more camber you use, the longer your braking distance and less traction accelerating out of a tight corner.

Yep. The speed and duration of the corners generally dictate the amount of camber you want to use at a given track I think.

 

[Roush_fan_99]

I think Roush has an allergy and keeps sneeze braking them!! Damnit!!

 

[Wilbur]

I think you might want to get that checked out!

Is it me or kind of weird when fixed setups are some of the best setups? There are a few tracks I've used them on open races with very good results. I'm enjoying this tire conversation as atleast im starting to understand some.

 

[Kamuifanboy]

I think you might want to get that checked out!

Is it me or kind of weird when fixed setups are some of the best setups? There are a few tracks I've used them on open races with very good results. I'm enjoying this tire conversation as atleast im starting to understand some.

Some of the fixed setups are quite good. But, for instance. The McLaren's fixed setup is a few seconds off the pace. Even with an alien driving it.