Tire locking behavior

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bristol87
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Tire locking behavior

Post by bristol87 » Thu Jul 18, 2013 12:02 am

Hi guys, I have a problem with my mod...Hope you can help me...

Which are the parameters that control the locking behavior of the tires?
I found that I can fully press the brake pedal during the entire braking zone, without locking the rear tires (even if I set a 46 front 54 rear balance) and only slightly the front ones...
I would want a car that locks a lot more...

I would also want a car that gets oversteer if you have such a balance, or if you quicly downshift (leading to oversteer or to front lock whether you have a rear balance or a front one)...

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Higpup
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Re: Tire locking behavior

Post by Higpup » Thu Jul 18, 2013 11:12 am

I know brake pressure has a lot to do with locking. If your testing at lower brake pressure that might be why. I have 93 brake pressure in our mod and after a few laps, I don't lock up unless I stay all the way to the floor for most of the braking zone. I don't think that's exactly what you were asking, but if you test the mod at 100% and can't lock the brakes, then I think the mod needs to be adjusted. If you're not at 100% pressure, you might want to try that first. Just a thought.
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bristol87
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Re: Tire locking behavior

Post by bristol87 » Thu Jul 18, 2013 12:24 pm

Higpup wrote:I don't think that's exactly what you were asking, but if you test the mod at 100% and can't lock the brakes, then I think the mod needs to be adjusted. If you're not at 100% pressure, you might want to try that first. Just a thought.
Yes I know that...I am trying it at 100%...but with lower brake balance (47 front and 53 rear) I never lock...If I set 55 front then yes, fron tires lock but you can downshift really faster and then "brake" with the engine, and I don't like this behavior too...

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Higpup
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Re: Tire locking behavior

Post by Higpup » Thu Jul 18, 2013 2:13 pm

bristol87 wrote:
Higpup wrote:I don't think that's exactly what you were asking, but if you test the mod at 100% and can't lock the brakes, then I think the mod needs to be adjusted. If you're not at 100% pressure, you might want to try that first. Just a thought.
Yes I know that...I am trying it at 100%...but with lower brake balance (47 front and 53 rear) I never lock...If I set 55 front then yes, fron tires lock but you can downshift really faster and then "brake" with the engine, and I don't like this behavior too...
Josh might answer this soon. He's the modder here. :D
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JohnW
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Re: Tire locking behavior

Post by JohnW » Thu Jul 18, 2013 10:09 pm

I must depend on how and when you apply the brakes. If I ran the brake bias you posted, I would lose the back end all the time.
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bristol87
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Re: Tire locking behavior

Post by bristol87 » Thu Jul 18, 2013 11:52 pm

JohnW wrote:I must depend on how and when you apply the brakes. If I ran the brake bias you posted, I would lose the back end all the time.
Yeah, I know that...Do you know what should I change to obtain that result?

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stuff
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Re: Tire locking behavior

Post by stuff » Fri Jul 19, 2013 11:03 am

Josh would probably have a better idea, but what could be a part of it is the parameter that controls brake strength based on temperature in your physics.hdv file:

BrakeResponseCurve=(050,550,750,1450) // First value is cold temperature (where brake torque is half optimum), min temp for optimum brake torque, max temp for optimum brake torque, and overheated temperature (where brake torque is half optimum)

What this does is adjusts how strong the brakes are depending on how hot they are. Lowering the overheated parameter (1450 in the example) will cause the brakes to become weaker more rapidly as they heat, making it easier to avoid lockups. Setting a high value for the overheated will cause the brakes to remain strong even at high temps (likely to be when you're at low speeds in a long braking zone) which will make it easier to lock them up.

there is a BrakeResponseCurve setting for each corner of the car, so if you tweaking it make sure you change all 4 :P, of course this will cause mismatches on servers that don't have the same modifications, but if you're developing your own mod locally it should be fine to play around with.

It could also be that your BrakeTorque setting is just too low as well. That one is also set per corner, and raising it will effectively make your brakes stronger and easier to lock, but it the mod is working otherwise and feels good but just doesn't seem to lock when it should, the response curve is probably what needs adjusting.

bristol87
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Re: Tire locking behavior

Post by bristol87 » Fri Jul 19, 2013 1:26 pm

Actually I have both values quite high...

BrakeResponseCurve=(-70,540,700,1730)
BrakeTorqueAI=3700.0

It's probably because the mod has been created by a real formula driver who exaggerated the speed feedback (we have 9** hp) and the grip level (to fight those horses), thus also the brakes values have been exaggerated (the braking zone is shorter then actual F1)...

Could it be the DecelSlip Curve of the .tbc file?

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Alaster
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Re: Tire locking behavior

Post by Alaster » Fri Jul 19, 2013 2:00 pm

Looks like you want to do some drifting or something... Maybe it is not the brakes performance itself but the "weight transfer" during deceleration that you want to change. I would try to adjust the springs and anti-roll bars. I think the diff values and gear ratios have something to do with it too. I don't know, I usually try to reduce rather than induce snap oversteer. You could try out some drift mods and see what values they run in their setup and performance files.
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bristol87
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Re: Tire locking behavior

Post by bristol87 » Fri Jul 19, 2013 2:18 pm

Alaster wrote:Looks like you want to do some drifting or something... Maybe it is not the brakes performance itself but the "weight transfer" during deceleration that you want to change. I would try to adjust the springs and anti-roll bars. I think the diff values and gear ratios have something to do with it too. I don't know, I usually try to reduce rather than induce snap oversteer. You could try out some drift mods and see what values they run in their setup and performance files.
No I don't like a rally car, it's a F1 :)
What I am missing is the rears locking...I want the drivers adjusting the brake balance toward 55, 58 front instead of 50 or 47...A real F1 car with a brake balance of 47 front is going to lock rear tires at >50% of turns...I never lock rear tires in canada too! Basing on your suggestions I am assuming that it's a exaggerated grip of rear tires in DecelSlip curve, could it be?

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stuff
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Re: Tire locking behavior

Post by stuff » Fri Jul 19, 2013 3:03 pm

bristol87 wrote: No I don't like a rally car, it's a F1 :)
What I am missing is the rears locking...I want the drivers adjusting the brake balance toward 55, 58 front instead of 50 or 47...A real F1 car with a brake balance of 47 front is going to lock rear tires at >50% of turns...I never lock rear tires in canada too! Basing on your suggestions I am assuming that it's a exaggerated grip of rear tires in DecelSlip curve, could it be?
It certainly could be, but I have no idea what would be reasonable values for making a custom slip curve. Might be best to just compare to other mods and see if they look out of whack.

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Re: Tire locking behavior

Post by JoshJ81 » Sat Aug 10, 2013 2:36 pm

Are you creating your own mod? If so and you want to lock up more, I would make your Longitudinal (front to rear movement) Grip values in the .TBC file lower. The Lateral value (side to side grip value) will not effect this near as much if at all. Less grip can cause more easy lock ups for sure. The F1 brake values that Stuff pointed out, are slightly modified from ISI's 2007 (maybe it was 2008?) BMW F1 mod. Be very careful with lowering that grip value because you will hurt driveability on exits. Wheel weight values can make a difference as well (heavier for more locking) but it will hurt exiting as well. Be careful with heating values, if you change braking values, you'll have to adjust heating values as well.

One other thing, I could lock up easily with those settings and a higher brake pressure setting in the garage (I typically run 85%). If you are not locking up at all at 100%, then you might want to make sure your pedals are calibrated and you might want to look at Wheel/Pedal settings within rFactor's controller menu. You can really change the effects of your rig with those settings from steering to acceleration to braking.

Sorry, for my late response.
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