confused is me

[Paul Monaf]

Hi guys just spent a small fortune joining i racing and I don't get it ( I'm confused as hell)
I get how to test the cars on the tracks, but that's about it
How do i take time trails or even race Im also finding the cars quite difficult to drive ( without aids) nd ant seem to find any set up in game that will help me
if ever there was a sim that needed iracing for dummies published this would be it
cheers
pul

 

[Xosé Estrada]

Sidewalls are included in that calculation. You have more use figuring out how to keep temperatures low and evenly spread over all four tyres.

I have the same problem with the C6R, the center is higher than the sides.

I understand the sides are not the usual sides temperature from other sims? They dont have to ha e the 6 degree dif with the center temp in between?

 

[Jan Roman]

Well, the rule of the thumb is that there should be maximum of 10 degrees difference (eg. I/M/O 100/110/100). The middle should be warmer. However, iRacing's interpretation of temperatures is a bit odd. People know about it. Some cars (like Mustang on the OTM) have the temperatures relatively right, on the other hand some cars (like the Corvette) have temperatures which don't seem real. I tried altering camber, caster and other things that might alter the temperatures, but it's still wrong somehow (eq. 70/80/90 or 80/70/80 and so on) so I learned nop to bother with it much.

I've read an interesting discussion recently. I found out that the temperatures matter a lot, but the grip is resulting mainly from pressure changes, not temperature itself. The tire has it's own operating value, but the grip curve and the slip angle varies A LOT (I mean a damn huge lot). There are tires with low melting points and optimal temperature around 60 °C, but there are tires designed to sustain a temporary stress over 500 °C. Right now in iRacing it seems that the grip curve is quite flat (read "wrong" since slicks usually have quite a narrow optimal temperature range). So that's why I don't really care about temperatures right now. What's more, simply look at the Corvette setups. The difference in pressures used is massive. For Watkins Glen people use over 180 usually, fixed is over 200 kPa. And at Mid-Ohio this week, Kay Kaschube used just 138 kPa

Please take into consideration that all the information is coming from what I've read so far. The problem is we don't know exaclty how the tire in iRacing work. We would need graphs for individual tires. It seems however (and it looks like Dave confirmed it) that our tires have their optimum range around 25 °C (he said "ambient") - that's why the "first lap qualification" bug exists. Then there's a small drop of grip, which drops again at very high temperatures (which occur during sliding). Now there's some kind of barrier to prevent cars from being too slippery after they start to slide (the difference is clear in the Corvette. I had an interesting slide yesterday at Mid-Ohio, which wouldn't be possible in the previous version).

I think the tires will become much more precise and complicated after another one or two builds. Flat spotting, vulcanisation and proper tire heating should come very soon.

Oh god, there's a good example how to write "don't bother with it" in three paragraphs!

 

[Yoeri Gijsen]

I have the same problem with the C6R, the center is higher than the sides.

I understand the sides are not the usual sides temperature from other sims? They dont have to ha e the 6 degree dif with the center temp in between?

I think that principle can still be valuable, but ti's more about how hot the actually get than about how the temps are spread. I think you can still compare left to right (but not middle!). If you don't keep to the 10-degree guidelines, you can still be fine, although high differences are going to be detrimental at some point.

As I said, you're probably better of comparing LF, RF, LR and RR to each other, than checking out the temperatures on one tyre.

 

[Hampus Andersson]

Yea tires are still very WIP-ish, As Roman says the optimal grip is at 20-25 degrees.
When it should be 90-110 depending on what tires are being used.

So instead of walkin up and over a hill we already start on top of the hill and it´s downhill from there on.

Hoping we get a nice update in the next build.

Oh, i think also the temps in game, or the outer temps also take into consideration part of the sidewall, the shoulder sort of. Hence they will look a bit weird.

 

[Xosé Estrada]

So around what pressures you usually use?

Because without counting with the temps, I dont really know were to go, grip changes are not always noticeable in pressure changes.

And tell me as well if this are read pressures, or "setup" pressures plz.

 

[Jan Roman]

Hard to say really. From what I've learned so far I do this (cold pressures):

The faster the track is the higher pressures I use. For example, at fast tracks with minor elevation like Spa, Okoyama, Motegi or even Watkins Glen, you can use even between 180-200 kPa. You'll feel the curbs more and the car doesn't respond so well, but there's is not so much tire wear I'd say. I can't really explain it properly since I don't fully understand it, but somehow higher pressures seem right at these tracks.

On the other hand technical and elevated tracks like Mid-Ohio are better with lower pressures since you need loads of grip. Lower pressures provide larger contact patch (notice however that the curve is not linear, the less pressure you have the warmer the tire gets -> the pressure rises). I used around 140 or 150 kPa this week, I am not sure right now.

I noticed an interesting trend. When I use lower tire pressures, sliding seems a bit more "right". For instance, during my race at Mid-Ohio, I experienced an amazing slide at T8 and T9. I didn't manage to save it, but anyway, it felt like a proper slide on a real road. On the other hand, hwen I use higher pressures, the car seems to be more prone to spinning and I can't save slides so often. But as I said before, I would worry about it too much. I often use baseline pressures since they usually fit the track and I am no alien so I can't really feel small changes. What I noticed is that I usually make the pressures lower, not higher.

I am waiting for the next update - I hope they'll intoduce flat spotting and correct the tire grip curve, it might solve a couple of things (in my head at least).

If you wish, I can post a video of this interesting slide (well, not really interesting, but it's interesting in terms of iRacing's physics). I can also provide Wtkins Glen and Mid-Ohio setups which worked well for me. At the moment, drivers are confused a bit and I don't think anyone knows exactly what's going on with our tires.

 

[Xosé Estrada]

Thanks Jan.

I also noticed a difference in slide an my possibilities to control it depending on the setup, but I never identified that pressures had a big influence.

This week I could also do nice controlled slides in T1.

A more predictable tyre temps and tyres would be good to enjoy setupping.

 

[Jan Roman]

I would like to correct myself.

It really bothered me so I took a look into some setups made by very fast people driving the Corvette (which is important, this may not apply to other cars). The trend is to use lower pressures very often. Even at Spa, I am now driving with 138 kPa (cold pressure) and it feels good. Tomorrow I will try to rise that pressure to 200 kPa (yes, that much) and see what's going to happen.

I think people would normally use such low pressure, but since our tires don't wear as much as they should (I think), there's no use using higher pressures for less tire wear.

 

[Yoeri Gijsen]

The thing you need to focus on with the NTM is tyre heat, not tyre wear. Keeping the tyres at acceptable temperatures while driving gives the most grip.

 

[Jan Roman]

If you mentioned it, I've done some research at Spa. I tested tire pressures and I have to say they have almost no effect at all. There's just a minor difference in grip and higher pressures make the car more unstable while riding over curbs. But right now, since we don't have a proper tire wear, I would recommend using the lowest possible pressure all the time (138 kPa cold pressure).

I've been also traking tire temperatures and I have to say Yoeri is completely right. For example, Eau Rouge and Raidillon at Spa arevery dangerous corners prone to overdriving. I am sure you've noticed that it's really easy to understeer there or go wide. This is caused by a massive rise in tire temperatures while you go up the hill after. While the tire temperatures usually operate around 80-90 °C and around 110-120 °C in corners, at T3 and T4 they rise up to 150 °C and the loss of grip is apparent.

 

[Xosé Estrada]

I would lo ve to have a tyre model where I can actually learn and use what I read from real racing setups.

Another thing I noticed is with the suspension, the dampers adjustment, at least in MoTec, have no big effect on the velocity, so you just have to setup them by feeling and not with data. This also means you normally end up with soft suspensions all the time.