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Unread 14 October 07, 12:52   #1
doo
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Default Tips: Learn how to brake

Yesterday I noticed that sim forums have tons of tutorials about single clutching methods downshifts and blipping the throttle while braking but there really isn't one decent guide about braking. People often may think that once they learn how to blip they know how to brake well enough. Of course, nothing could be further from the truth, so, I decided to share some views on braking. On some parts I have relied on Carroll Smith's article 'Brake To Win' in an ancient Race Tech magazine.


Getting to know the basics

Theoretically, the idea of braking is to go from maximum acceleration to maximum deceleration as quickly as possible without upsetting the car too much, then to modulate the braking force applied so that the tires are all the time on the edge of traction, and finally to smoothly release and commence either trail braking or cornering. So, basically you have three parts to the braking process:

1) Building up the braking force
2) Slowing down the car and modulating the braking force
3) Releasing the braking force

Messing up any one of these phases usually causes you to mess up your corner entry. Let's take a look at the most common consistent mistakes that drivers sometimes do.

Phase One

a) Probably the most common mistake in building up the brake force is not to get on the brake pedal hard enough. This means that you are taking too long to build up brake force and that you could do it faster without upsetting the car. This causes you to lose time.

b) Another common error is to jump on the brake pedal too hard. This causes the front tires to compress and causes a spring-like movement in the front end of the car making it impossible to modulate the brake force efficiently.

c) Braking too early is a common novice mistake. Usually this problem easily disappears with the help of a little practice. Anyway, if you find yourself coasting (or in the worst case accelerating again) after braking into a corner, you know you messed up real bad. This usually ruins your lap time more or less.

d) Braking too late doesn't do you any good either. This will cause you to arrive at the turn in point too fast and to miss the apex. If you already missed your brake point, be careful not to make things worse by trying to brake harder! If your brake point is accordingly selected, you shouldn't be able to brake any harder! Trying to make the car stop in shorter distance will only cause you to either build the brake force too fast thus upsetting the car and making the braking even more difficult, or either to apply too much force during the modulation which will then cause the tires to lock up.

Learning how to judge where the optimal braking point is is perhaps one of the two most difficult parts to the braking process, especially under changing weather conditions and the tires wearing down. The other one is judging when to release the brakes in order to have enough time to balance out the car before turning into the corner.

If you miss the brake point, you have three options.

d1) You can try to manouver through the curve with a larger turn radius, in other words, short-cutting the corner. This usually involves your car wildly bouncing over the kerbs and acting as a lawn mower, but when done properly, it keeps you in the race and minimizes your time loss.

d2) Sometimes manouvering through the curve just isn't possible anymore. At this point, you ignore the corner and concentrate on slowing the car down enough to keep it from hitting into anything solid. If you succeed before you run out of tarmac, you can go about your race.

d3) Sometimes even braking in a straight line won't slow the car down enough to keep it on the track. At this point you still have one option: you intentionally force the car into a skid and slide of some of the speed. This way once you manage to slow down enough to gain traction (if you still are on tarmac) your car is already pointing in the correct direction.

This way you can bring your car about in a few meters shorter distance. Comes in especially handy when it's the few meters you don't have. Note that this is a highly sophisticated technique and requires a lot of practice but once mastered, it also provides you with a great overtaking tool: you can brake a fraction of a second later than the guy in front of you and slide off the excessive speed ending up right in front of him. This technique is very consuming on the tires.

Phase Two

During the "hold" you must remember that as you lose speed, you lose downforce. Less downforce, less traction. Less traction, less brake force. So, you have to ease up on the pedal while you slow down to stay on the edge of traction without locking up. There are really only three things you can do wrong during this phase.

e) Not easing up enough on the pedal. This will cause you to lock up one tire or multiple tires as the traction lessens. Although the car would in fact slow down faster with all tires locked up, there are some side effects to this and therefore it is undesireable. First of all, it will ruin your tires. Secondly, you this may cause handling issues during the braking. The result of all this is that you will have to lift your foot up from the brake
pedal quite a lot to regain control and to unlock the tires. This, of course, will completely ruin your effective deceleration.

f) Easing up too much on the pedal. As you slow down, you are no longer on the edge of traction and are not decelerating efficiently. This will cause you to lose time. Remember that still, this is usually a better option than locking up.

g) Messing up the downshift. This can be done in multiple ways and I feel that there are plenty of tutorials out there concerning this topic, so I will leave this question outside this tutorial.

Although I will say one thing. Some of you may believe that downshifting is a genious help during the braking in slowing the car down. This is basically a general misconception. Downshifting is not the big help you thought it would be! Yes, reving the engine will slow the car down. But there are certaing problems that are caused by using the engine to decelerate.

1) It only affects the driving wheels.
2) It makes the proper modulation extremely difficult.
3) It puts unnecessary stress to the engine and transmission.

If you cannot slow the car down fast enough without using the engine to help, the only thing that means is that your brakes are set up incorrectly! Almost every driver will stop the car noticeably faster when not downshifting at all. I'm not saying that downshifting couldn't help you, but I strongly suggest you learn how to brake properly before trying to adapt all kinds of cool gimmicks. Sit down and ask yourself the question are you REALLY downshifting as well as you think you are? Is it helping you because you are so good at it or is it helping you because your normal braking is crap?

Remember, the secret of efficient braking is not who can brake deeper! It's who can brake later and still enter the corner with the car in balance at the entry speed calculated to combine optimum apex speed with maximum acceleration out of the corner with minimum loss of speed going in. So, even though the downshifting might help you slow the car down faster, it doesn't mean that you are cornering more efficiently!

Phase Three

This is perhaps the most difficult part of the braking process. A few things can go wrong here as well.

h) You lift off the brake pedal too fast. This will affect the pitch attitude of the car and cause some understeer as the front end lightens. Those of you that have more experience with Porsche or other rear-engine designs may have noticed how lifting the brake pedal too fast while turning causes the car to spin. So beware of that.

i) You lift off the brake pedal too slow. This means you could have done it faster without upsetting the car too much. This will increase the braking distance and thus cause you to lose time.

j) You lift off the brake pedal too early thus entering the corner too fast and fail to launch out of the corner properly. This will cause you to lose time. On some occasions you may even have to jump on the brake pedal a second time to slow the car down enough thus failing the proper race line, corner entry and launch out of the corner.

k) You lift off the brake pedal too late. You miss the turn in point and thus the apex and lose your momentum failing the proper race line, proper corner entry and proper launch out of the corner.


[Continues in the next post]
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Unread 14 October 07, 12:53   #2
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Default Part 2

Trail braking

Trail braking means braking well into the corner entry phase at a reducing or "trailing off" level. This means the tires are still contributing braking thrust while in the process of building up cornering force. This way the driver is taking advantage of all the potential traction the tire has to offer. In other words, the driver is staying on the edge of the traction circle as much as possible. This, when used properly, can save time.

Trail braking is basically an invert launch out of the corner. When exiting a corner you apply more throttle the further you go as you don't have to steer that much anymore. In the same way when entering a corner, you don't have to steer that much in the beginning, so you can use some of the traction available for braking. It's that simple.

Learning the technique is the easy part of trail braking. Getting to know when to use it is the difficult part. Every successful driver trail brakes in some corners. No succesful driver trail brakes in every corner. But how to determine when to trail brake and when not to?

1) How much time is available for blipping and clutching? Remember, taking your foot off the brake pedal is one of the hardest things to do well in the braking process.

2) How much front lateral tractive capacity will be necessary for turn in and how much of it will be provided by downforce?

3) How much steering input is required for turn in and how quick will that steering wheel movement be? In other words, how tight is the corner?

4) How badly is your car understeering?

5) How fast is the corner?

Trail braking can significantly reduce corner entry understeer due the combination of pitch attitude change (lessened traction in the rear) and increased the vertical load on the front tires. Keep in mind that if you have set up the car to use trail braking to kill understeer, when you don't, the understeer returns. This kind of setup requires you to be very committed to driving at 100 % all the time.

Finally, a few things to remember about trail braking:

1) It doesn't work on fast corners (unless done with the left foot against partial power) because it changes the pitch attitude of the car.

2) It doesn't work on bumpy corners.

3) It doesn't mean braking hard into the corner. It means trailing off the brakes as you enter the corner.

4) In a race, if in doubt, don't do it. Slow in and fast out beats fast in and slow out.


Setting up the car for braking

The most important setup factor from the standpoint of braking is the brake bias. Usually the brake bias should be slightly front biased. I cannot give any ratios because this is so much affected by so many factors. The better you get at braking, the furter you can adjust the bias towards the rear end.

Very few sim racers take advangate of the cockpit brake bias adjuster. The optimal brake bias is affected a lot of factors, so learn to use the adjuster while driving! A few of those factors:

1) The weather. If it starts to rain, you'll need to adjust the bias towards the rear end.

2) Fuel load. A car set up for a light load may well have a rear biased optimal balance with the tank full.

3) Tire wear. As the tires wear out, you'll need to go towards the rear end in the bias a bit.

I cannot emphasize on this enough: learn to adjust the brake bias while driving. Try to make it a routine to pay a little attention to the brake balance every few laps and always right after pitting.

Finally, if you just can't seem to get your braking right and the car keeps squirming all over the place, be sure to check these:

1) Brake bias. The biggest single factor affecting car behaviour while braking. Understeer, too much front bias. Oversteer, too much rear bias.

2) Ride height. Are you bottoming out? Also, try limiting the pitch attitude change speed by stiffening the springs a little and by increasing slow bump value in front.

3) Is the suspension bottoming out? Not as violent effects as the whole car bottoming out, but still quite nasty. Same as above, stiffen the springs and increase the slow bump value in front.

4) Do you have wild amounts of static toe in or toe out at one end of the car? These will cause handling issues.

5) Too much front load? Less wing.

If the car is stopping just fine on smooth corners but is all over the place on bumpy corners, your shocks are messed up. Especially pay attention to the rebounds, if that is the case.

Well, hope these pointers helped someone. Lemme know what you guys think.
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Unread 14 October 07, 17:49   #3
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Thanks, man...nice guide
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Unread 14 October 07, 17:56   #4
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Awesome - thanks for taking the time to post.
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Unread 14 October 07, 18:50   #5
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Thanks for the feedback, fellas.

A few things I might still add concerning braking and cornering:

For all you beginners out there, the key element is to be smooth. Even though you are trying to go as fast as possible, you never want to upset the car balance any more than is necessary. Keep your steering input as small as possible. Be swift and determined about your handling but don't jerk.

Pay attention to your turn in point! Almost all novice drivers turn into the corner far too early. When the corner is approaching you should be thinking about your braking, not steering. Be patient, don't turn in too early. It will mess up your corner exit.

In a normal corner, you shouldn't apply any steering input at all before you're done with your modulation and are commencing the release. At this point, you should be at the very far edge of the road opposite to the corner. If you find yourself in the middle of the road, you turned in too early. Once you get this right, you'll notice a significant improvement in your laptimes.

For you more advanced drivers, don't underestimate the advantage of a good braking! You might feel it doesn't matter that much, but think about this. Statistically, on average, you are braking about 10 % of the time. So, a 2.5 % improvement in your braking performance will squeeze of 0.25 % of the laptime. On a 1 min 30 sec laptime that makes 0.225 seconds. In a two-hour race: 18 seconds. And that's only 2.5 %...
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Unread 14 October 07, 19:22   #6
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hmm interesting

thanks
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Unread 14 October 07, 21:50   #7
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Thanks for sharing mate!
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Unread 15 October 07, 05:28   #8
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Still forgot to mention one little thing. If you're locking up a lot, one thing that might help is to drop the brake pressure from 100 % to around 95 %. But that's something you should do ONLY if you're experiencing problems. Not as a routine adjustment.
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Unread 15 October 07, 16:10   #9
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thank you very much for this guide!!!! this is EXTREMELY helpful, even in helping me begin to learn to better tweak my car.

last night I played with the bias on the P&G cars, and it really helped me pick up my lap times in the Mustangs.

i also played with the cockpit bias adjustment in race '07....REALLY helps with the FWD cars!!!
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Unread 15 October 07, 19:37   #10
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Very helpful, one for printing and filing, many thanks.
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Unread 15 October 07, 20:02   #11
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Something else also......I have turned down alot of the car sounds, EXCEPT for the SCRUB, and SKID sounds which I took up to like 150%. That way I can easily hear the tires hollering in a corner, or the skid if I am locking up my brakes. Being able to hear what I'm doing to the tires, has helped me be smoother overall, and improved my lap times to boot!
Great post Doo!

Phil
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Unread 16 October 07, 10:30   #12
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Very good so i've made it sticky :cool:
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Unread 16 October 07, 11:38   #13
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WOW Lots of thought there... many thanks!
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Unread 16 October 07, 13:39   #14
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Quote:
Originally Posted by KarlosDaJackal View Post
Very good so i've made it sticky :cool:
Peanut-butter jelly!

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Unread 16 October 07, 13:47   #15
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Quote:
Originally Posted by PhilH959 View Post
Something else also......I have turned down alot of the car sounds, EXCEPT for the SCRUB, and SKID sounds which I took up to like 150%. That way I can easily hear the tires hollering in a corner, or the skid if I am locking up my brakes. Being able to hear what I'm doing to the tires, has helped me be smoother overall, and improved my lap times to boot!
Great post Doo!

Phil
I do that as well and I use the brake noise mod which seems to make the brake sound audible at around 3rd to 2nd when the wind noise http://gtr4u.de/jgs_db.php?action=sh...s_id=2560&sid= and downforce subside a little.
( with the afore mentioned sound settings with elevated road noise setting makes the buttkicker feel like road vibrations of speed, as the wind noise is increased with speed.
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Unread 26 October 07, 17:02   #16
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Well i got a Q : im playing with a cotroller and im locking up the tires in slow corners
its like this i brake and shift down and right before i wanne steer in corner the wheels lock up and its always the front tires
any suggestions
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Unread 27 October 07, 12:24   #17
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Quote:
Originally Posted by fenix View Post
Well i got a Q : im playing with a cotroller and im locking up the tires in slow corners
its like this i brake and shift down and right before i wanne steer in corner the wheels lock up and its always the front tires
any suggestions
1. Are you modulating the brake force enough? Remember, less downforce, less grip.

2. Are you releasing your brake force too rapidly causing the body to swing backwards and lighten the front end? If so, increase slow bump values.

3. Is your brake bias too front biased?

4. Is the corner bumpy? If so, try dropping brake pressure to around 95 %. Also, adjust the dampers around and see if it helps.

5. Are you drifing a FWD car? If so, are you screwing up your downshift?


Let me know if these tips were of any use...
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Unread 8 November 07, 19:02   #18
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Very, very good, many thanks doo!
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Unread 11 November 07, 17:40   #19
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Thank you doo, I printed them out to read when I can't be racing. . Any help in set up and proper racing techniques is always appreciated, Thanks
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Unread 23 November 07, 17:15   #20
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Great read doo and thank you for posting this. I have found many drivers that have no idea about the in car brake bias adjustment. That is a great help in extended races where your noting tire wear, weight shedding (fuel usage). I also use the brake squeal mod as this tells me audibly when the brakes are near locking.. very handy. (ps i don't use the gravel sounds from the mod as it's too loud)
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Unread 28 November 07, 03:57   #21
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Hey doo--great primer!! Yup, we'll print this one for reading when Grandma is tying up the machine e-mailing the "relies".

I appreciate generous people--like you!
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Unread 16 December 07, 21:54   #22
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Great guide doo, but you forgot one thing that I am guilty of all the time. I seem to keep my right foot on the throttle just a little while braking. Some times more, some times less, but almost always I have some throttle going to the engine. This will slightly or greatly increase brake distance and wear out brakes faster,
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Unread 17 December 07, 05:19   #23
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Quote:
Originally Posted by gearjammer View Post
Great guide doo, but you forgot one thing that I am guilty of all the time. I seem to keep my right foot on the throttle just a little while braking. Some times more, some times less, but almost always I have some throttle going to the engine. This will slightly or greatly increase brake distance and wear out brakes faster,
Well, seems like you have accidentally found a technique widely known as "left-foot braking". It means that the driver is still applying some throttle while applying brake force. If used correctly, it will reduce the braking distance, not increase it. Most performance cars are quite well designed to withstand the additional physical stress caused by this technique.

In race track driving, left-foot braking is used to reduce the longditudinal pitch attitude changes involved with the braking process and sometimes as a last resort to kill understeer. It also functions as a manual traction control method, especially while trail braking into high speed corners and while exiting slippery corners.

In rally driving it is in addition used to override central differential locking and to perform the scandinavian flick among a few other things, like keeping up the turbo pressure in a corner to ensure a perfect corner exit.

However, it is obvious, of course, that applying throttle while braking isn't something you should be doing as a standard procedure.
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Unread 17 December 07, 07:22   #24
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So basically, if I am going to be using the brake and the throttle at the same time, then I would need to modulate both the brake and the throttle to reduce brake distances as well as to keep the car in balance?
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Unread 17 December 07, 09:03   #25
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If you haven't found a use for it yet: the gear lever of the Momo or G25 can be used to adjust brake bias while driving.
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Unread 17 December 07, 09:29   #26
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Quote:
Originally Posted by gearjammer View Post
So basically, if I am going to be using the brake and the throttle at the same time, then I would need to modulate both the brake and the throttle to reduce brake distances as well as to keep the car in balance?
Well, in track racing, left-foot braking isn't really used for that kind of braking... It's mainly used in high speed corners where that much modulation isn't needed (as you never slow down enough to essentially lose the downforce) and places where the tail of the car gets light even without braking, for example in corners going over hills. Places where you cannot afford the rear end to lighten up that much. The Corkscrew of Laguna Seca would be a good example of a place where left-foot braking is helpful despite the low situational speed.
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Unread 17 December 07, 15:14   #27
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My biggest gripe about this game is the same as with FPS shooters. People do things
they would NEVER do in real life.. Charging into battle knowing what the hell I'll get a
couple kills, die and then respawn..

Rather than easing into a corner and waiting to pass a slower cars at the right time,
they just barrel through everyone to in effect BUMP them off the track completely. It's hard enough as a beginner to keep up and race, but with these guys just pushing you around on the track, it just sucks.

Well with GTR2, these guys will ram into you knowing they can just continue on..
And then 80% of them just leave the game if they are not in the top 3 right
off the bat. They just give up. It is so frustrating.. Honestly every game I join is
like that. We start off with 8-10 cars and within the first lap, 6-7 drivers leave the
game.

Is the most important thing to these guys hitting the fastest lap times, or staying in
the races without being dirty or just plain stupid?
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Unread 18 December 07, 11:17   #28
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Quote:
Originally Posted by Mshine View Post
My biggest gripe about this game is the same as with FPS shooters. People do things
they would NEVER do in real life.. Charging into battle knowing what the hell I'll get a
couple kills, die and then respawn..

Rather than easing into a corner and waiting to pass a slower cars at the right time,
they just barrel through everyone to in effect BUMP them off the track completely. It's hard enough as a beginner to keep up and race, but with these guys just pushing you around on the track, it just sucks.

Well with GTR2, these guys will ram into you knowing they can just continue on..
And then 80% of them just leave the game if they are not in the top 3 right
off the bat. They just give up. It is so frustrating.. Honestly every game I join is
like that. We start off with 8-10 cars and within the first lap, 6-7 drivers leave the
game.

Is the most important thing to these guys hitting the fastest lap times, or staying in
the races without being dirty or just plain stupid?
This post doesn't belong to this thread... It would be better suitable in the GTR2 Multiplayer section of the forum. You are seriously derailing this sticky thread, so please, stick to the topic -- braking, that is.
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Unread 19 December 07, 22:29   #29
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Your first post indicates that locking up the tires (skidding) will stop you quicker than not locking up in an emergency. The books I read (Going Faster) state strongly that a lockup will increase your stopping distance because you have lost adhesion with the pavement.

Basically, a lockup not only eats your tires but increases stopping distance. However, tire squeal (not to the point of a lockup) can be an indication of efficient traction control.

But, I am not a race driver, I just read books by racing professionals.
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Unread 20 December 07, 07:12   #30
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Quote:
Originally Posted by Gutshot View Post
Your first post indicates that locking up the tires (skidding) will stop you quicker than not locking up in an emergency. The books I read (Going Faster) state strongly that a lockup will increase your stopping distance because you have lost adhesion with the pavement.

Basically, a lockup not only eats your tires but increases stopping distance. However, tire squeal (not to the point of a lockup) can be an indication of efficient traction control.
This matter is somewhat disputable. From the standpoint of physics, slide friction is always greater than rolling friction... So, if the tires never bounce off the surface, the fastest negative acceleration would be acchieved by locking the brakes. The reason why lock-ups usually increase braking distance is the fact that you have to ease up on the brake pedal to unlock the tires, because you still need them unruined and you might have to steer the car while braking. On the other hand, the rolling tyre could be considered to be in a constant state of static friction... It's not easy to say.

During rain, the case is different when hydroplaning, because the tyre loses contact to the actual surface.

When race cars spin at high speed they often seem to lose all grip and slide to the wall without ever really slowing down that much. And they actually don't. But mostly this is caused by the loss of all downforce, not the loss of tyre traction due to skidding.

But like I said, I've heard a lot of theories on both sides of the matter.
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Unread 9 January 08, 09:34   #31
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Great thread, thanks doo !

Could you give some pointers, from the better braking point of view, on the following please?

1. Human input devices, ie. the brake pedal we actually use to effect the simulation environment, in particular the sensitivity set up of this.

2. Motec information and optimum brake temperature

Thanks again.
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Unread 10 January 08, 10:34   #32
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Quote:
Originally Posted by Willy View Post
Great thread, thanks doo !

Could you give some pointers, from the better braking point of view, on the following please?

1. Human input devices, ie. the brake pedal we actually use to effect the simulation environment, in particular the sensitivity set up of this.

2. Motec information and optimum brake temperature

Thanks again.

Computer racing pedals aren't really anything like real hydraulic brake pedals since you have no "force feedback". Although, you can't really feel tyre lockups with real pedal either. The only main difference is that most controllers have all three pedals in same height (which makes downshifting a little more difficult), whereas the brake should be higher than the throttle so that when braking, you can still reach the throttle with your heel. The other main difference is that race car brake pedals usually require a lot of force to get maximum deceleration, up to 50-60 kilograms.

The best sensitivity setting is such that allows you to have as accurate control as possible. So, no dead zones and a linear use of the full axis length is best I think.

MoTeC is a valuable tool when evaluating your own braking performance. In the attached image we have six diagrams:

1. Front wheel speed lines
2. Rear wheel speed lines
3. Longditudinal G-Force
4. Brake pedal position
5. Throttle position
6. Gear

The data is from Imola beginning from the braking after Tamburello into Villineuve chicane and then on to Tosa (corners 4, 5 and 6).

Now, your most important tool is the G-Force graph because it shows you how much negative G's you are pulling. In other words, it tells you how effectively you are slowing down. After all, that is the purpose of braking, as long as you are not upsetting the car too much. You want the line to be as deep as possible and as level as possible, because this means your braking is smooth. When it's not smooth, it means you could be braking harder.

You can see that in the first braking I'm pulling about -1.7 G and into the second corner of Villineuve around -1.6 G. This is the level you should be aiming for. If you're pulling less G's or your G graph is unlevel, something's not right.

In the third braking you can see that the G-line only goes to about 1.4-1.5 G, it isn't level, and in the end of the braking it drops down to -1.1 G. So, this braking isn't good. First of all, you can tell by my brake pedal position that I'm not braking with full power, because I know that Tosa is a bumpy corner. The actual reason, however, can be found when looking at the wheel speed graphs. At the end of the third braking you can see one red spike and a lot of orange spikes pointing downwards. This means that the left side wheels are locking up a little (they are spinning slower than the right side wheels which are not locking up but rolling smoothly). On top of all that, I picked the worst possible moment to downshift, which further upsets the car. As a result of the lockup, I have to ease off the brake pedal a little, which drops the G's to -1.1. I found out looking at my virtual cockpit that I was applying a little bit of steering input to the left while braking. This probably caused the left side of the car to lighten up and the left side wheels to go over the traction treshold thus locking up.

So, MoTeC tells you exactly what you did wrong and where you did it.

Unfortunately, I can't give you a good answer on the brake temperature in GTR2. Perhaps someone else could help with that..? Anyone?


EDIT: I haven't talked a lot about downshifting, so I thought I'd just mention something. A lot of people talk about blipping the clutch and all that when downshifting, but I don't think it's necessary. You can see that during the second braking, I downshift without even touching the clutch and I still pull -1.6 G's without locking up one slightest bit. You can see that when I downshift, I just ease up on the brake pedal from 100 % to around 95 % to compensate. The only side effect is that the G graph momentarily goes down to -1.55 G. This is just one way of downshifting, but so that you all know, it's possible to brake well while downshifting without blipping anything.
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Last edited by doo; 10 January 08 at 11:21.
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Unread 10 January 08, 15:44   #33
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Unfortunately, I can't give you a good answer on the brake temperature in GTR2. Perhaps someone else could help with that..? Anyone?
Optimum brake temperature in GTR2 is defined in the .hdc file of the car, by the following two parameters:

BrakeOptimumTemp=450.0 // optimum brake temperature in Celsius
BrakeFadeRange=450.0 // temperature outside of optimum that brake grip drops to half (too hot or too cold)

Above values are the same for all cars that come with the game except for the MC12, where it is 500/500.

Prototypes and Group C cars are set to 750/750.
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Unread 10 January 08, 20:18   #34
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Optimum brake temperature in GTR2 is defined in the .hdc file of the car, by the following two parameters:

BrakeOptimumTemp=450.0 // optimum brake temperature in Celsius
BrakeFadeRange=450.0 // temperature outside of optimum that brake grip drops to half (too hot or too cold)

Above values are the same for all cars that come with the game except for the MC12, where it is 500/500.

Prototypes and Group C cars are set to 750/750.
This is really helpful to me, so please explain further. I can understand BrakeOptimumTemp=450 celsius would give you the best brake performance. Very useful information. Where I am confused is with BrakeFadeRAnge=450. Does that mean that you only get 50% braking if you are not at exactly 450? I must be missing something (which is not unusual).

Additionally, a previous poster indicated that in GTR2 you can downshift without using the clutch pedal without disaster (apparently in H-shifter mode- because you dont use the clutch pedal downshifting in paddle mode anyway). That has been my experience when dropping from 6th gear to 5th when braking from flat out in the Viper, but if I try to drop from 6 to 3 without clutch it makes a mess. Question: is this real life realistic or just a GTR quirk that allows for learning bad habits that dont translate to real driving?
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Unread 10 January 08, 21:23   #35
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Very useful information. Where I am confused is with BrakeFadeRAnge=450. Does that mean that you only get 50% braking if you are not at exactly 450? I must be missing something (which is not unusual).
Fading of the brakes basically means losing the brakes. So, it probably has something to do with that.


Quote:
Additionally, a previous poster indicated that in GTR2 you can downshift without using the clutch pedal without disaster (apparently in H-shifter mode- because you dont use the clutch pedal downshifting in paddle mode anyway). That has been my experience when dropping from 6th gear to 5th when braking from flat out in the Viper, but if I try to drop from 6 to 3 without clutch it makes a mess. Question: is this real life realistic or just a GTR quirk that allows for learning bad habits that dont translate to real driving?
I never use the H-shifter, just up and down. You can use the clutch, no matter what shifting method you are using, stick, pads, buttons or automatic.

You can't drop straight from 6 to 3, you have to shift at low revs, one by one. Unless you disengage the clutch, go to 3, throttle the revs up and engage the clutch again at the correct revs. Like I said, there are many ways to go about the shifting process.

Today's racing sims are still pretty far from reality in many ways. Most importantly, real-life driving is physically consuming, whereas sim racing... not that much.

Anyway, I better stop posting, because I am fairly intoxicated right now.

Last edited by doo; 10 January 08 at 21:31.
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Unread 10 January 08, 22:45   #36
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Where I am confused is with BrakeFadeRAnge=450.
It means 50% brake power at both 0 and 900 deg Celcius.
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Unread 9 March 08, 16:20   #37
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when ever i try braking i usally lose the back end ,into slow corners.or it locks the front wheels so badly that the car ends up facing the on coming cars.
lot of people tell me to take it easy with the brake,but watching the amount of pressure on the g25 calibration screen doesn't correspond with the brake levels applyed.
i can just touch the brake pedal and most of the time during testing calibrations the brake is only 50% across the screen.
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Unread 9 March 08, 18:45   #38
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When you calibrate the G25 pedals it should take full down motion to have the red line max out. It should be propportional in that a little brake pedal movement should produce a little braking. If not you have problems.

If you spin under braking, move the brake bias forward at least to the point that you can hit the brakes hard when traveling in a straight line and not lose the rear end.
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Unread 17 March 08, 20:44   #39
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hi, thanks for the guide... i found it very useful... but one thing i noticed that is under played throughout this thread is the importance of weight transfer...

waiting for the weight transfer during braking is one of the most important things i learned as a motorcyclist... unlike in a car, you can not afford to lock up the front brakes on a motorcycle... locking it up will almost certainly bring you to the ground...

aero dynamic downforce is still very important, but even F1 cars with the best aero dynamic downforces only produce about 2G's at top speed... those same cars are able to produce over 4G's (most of which are directed to the front wheels) under braking...

this is the reason why staged braking is very effective... in essence, the driver is waiting for the weight to transfer forward on to the front wheels BEFORE piling on the brake preassure... that is the reason why it is very easy to lock up the front wheels when you slam on the brakes while going full speed...

in regards to tires sliding: once a tire is sliding, it is in kinetic friction... studies have shown that with regards to tires on road surfaces, static friction is almost always greater than kinetic friction (which is even true for tires on ice)... also, it is a pretty safe to assume that the kinetic friction of brake pads against brake rotors is substantially greater than the kinetic friction of tires against the ground...

Last edited by flipteg; 17 March 08 at 20:50.
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Unread 24 March 08, 15:53   #40
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Originally Posted by flipteg View Post
hi, thanks for the guide... i found it very useful... but one thing i noticed that is under played throughout this thread is the importance of weight transfer...

waiting for the weight transfer during braking is one of the most important things i learned as a motorcyclist... unlike in a car, you can not afford to lock up the front brakes on a motorcycle... locking it up will almost certainly bring you to the ground...

aero dynamic downforce is still very important, but even F1 cars with the best aero dynamic downforces only produce about 2G's at top speed... those same cars are able to produce over 4G's (most of which are directed to the front wheels) under braking...

this is the reason why staged braking is very effective... in essence, the driver is waiting for the weight to transfer forward on to the front wheels BEFORE piling on the brake preassure... that is the reason why it is very easy to lock up the front wheels when you slam on the brakes while going full speed...
That's pretty much what I meant when I was talking about building up the brake force properly without upsetting the car too much. I could have been clearer on the matter, though.

Quote:
in regards to tires sliding: once a tire is sliding, it is in kinetic friction... studies have shown that with regards to tires on road surfaces, static friction is almost always greater than kinetic friction (which is even true for tires on ice)... also, it is a pretty safe to assume that the kinetic friction of brake pads against brake rotors is substantially greater than the kinetic friction of tires against the ground...
The dilemma is really not whether the friction of the brake pads against the brake discs is greater than tire friction against the track, because regardless whether the tires are locked or rotating, the only thing that matters in slowing the car down is the friction between the tarmac and the tires.

(If the brakes are able to lock the tires, the brake friction is larger than tire friction because the motion of the road surface underneath the tire is not able to force the wheel into motion while the brakes are holding it still. If the tires won't lock, the brake friction is weaker than the force coming from the road. The greater force dominates.)

So, the dilemma is whether a rotating tire is longditudinally speaking in a state of rolling friction (which would be smaller than sliding friction, meaning that a locked tire would stop faster) or in a dynamic state of static friction (which would be larger than sliding friction, meaning that a locked tire would stop slower than a rolling tire).

Concerning lateral tractive capacity the matter is quite simple since the tire is not rolling sideways. Therefore, it is in a state of static friction and locking the tire will cause it to enter a state of sliding friction, laterally (and longditudinally) speaking. In English, locking up the tires reduces lateral traction meaning that when front tires lock the car won't turn and when rear tires lock the rear end will spin.

(Giving too much throttle will also spin the rear end because once the rear tires start spinning faster than the tarmac is going underneath them, they again lose the state of lateral static friction and enter a state of sliding friction, thus reducing lateral traction. For the same reason, a FWD car will not turn if the front wheels are spinning too fast.

This is also the reason why one should always try to apply steering input into the direction of the skid so that the front tires would face the direction of the car's momentum and start rolling again thus coming out of the state of sliding friction back to the state of lateral static friction thus regaining traction and the control of the vehicle.)


Ice is a very different surface than tarmac. Over here the roads are (or at least used to be) covered by ice about 5 months and plain tarmac the rest of the time, so I would know. The reason why ice is slippery cannot be scientifically explained at this time. Slipperiness is a unique characteristic of ice as a material and therefore comparing it to tarmac isn't really rational in this matter.

But like I said before, it's really not that simple and I've heard a lot of theories on both sides of the matter.
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Unread 24 March 08, 17:17   #41
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Ice theories about slippriness vary wildly and there is no consensus. It is clear here in the Alaskan interior that ice is much less slippery at -40 than at 0 F. (If I want to miss hitting a caribou or moose on the highway, I have a better chance in colder weather.)

Friction between warm tarmac and tires is also somewhat difficult to theorize about, but less confusing than why ice is slippery.
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Unread 24 March 08, 19:20   #42
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Ice theories about slippriness vary wildly and there is no consensus. It is clear here in the Alaskan interior that ice is much less slippery at -40 than at 0 F. (If I want to miss hitting a caribou or moose on the highway, I have a better chance in colder weather.)
I concure.
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Unread 25 March 08, 09:50   #43
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The main thing that I have noticed as a problem, especially in instances where the driver is under pressure from other drivers. When a driver believes (s)he needs to go faster to outrun an opponent, he might be too abrupt with inputs and break the stability of the car.

Jumping off the throttle and slamming the brakes is a commonality because it induces a trail-braking over steer situation: Under throttle, the front end of the car will rise if only a small amount, and the back end will sink by a small amount. When the throttle is cut, the front drops and the rear rises, slamming on the brake hard will further the front end drop and rear end rise. Which, in terms of chassis dynamics will cause down force to lift off the rear end (actually, it is weight transferring forward via momentum, but to make it easier to understand, you can call it a loss of down force if ya like.)

Basically, if the guy behind you has the horsepower, he'll pass you eventually no matter how hard you try to hold him off. The general rule of thumb for me is that if he is a half mile behind and then becomes a half car length behind me while I am making a perfect run, he's already shown me he has the horses and I am not going to be able to hold off the onslaught and might as well allow him by to avoid an accident. And, just because he has outrun me doesn't mean I am not longer a problem for him! Generally unless there is a major difference in performance, I can at least keep up and hope to capitalize on his every mistake.

A much better option is to try and out-corner an opponent as opposed to out-braking him. If you think you can hold him off, take the choice line and block a little. Know your vehicle and use its advantages to your benefit, if you've got a car that corners like a bread truck, but accelerates like a rocket, then maybe you can allow the opponent up beside you, but then outrun him down the straights? If cornering is superior to acceleration, maybe you could block down the straights?

In the very end, driving deliberately and hitting your marks carefully and smoothly will get you better lap times than changing your style just because somebody is putting pressure on you.
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Unread 26 March 08, 08:23   #44
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The main thing that I have noticed as a problem, especially in instances where the driver is under pressure from other drivers. When a driver believes (s)he needs to go faster to outrun an opponent, he might be too abrupt with inputs and break the stability of the car.
It's a common psychological problem. While entering the braking you fear that the guy behind you will outbrake you. The most common form of this problem is fearing that you will brake too early. The result is that you miss the brake point and thus enter the corner too fast, miss the apex and leave a hole for the overtaker.

Another common thing is that once you know that you easily over-estimate your grip under pressure, you tend to be too careful and commence braking too early.

The way I overcome this problem is that I tell myself again and again that if I choose the best line and brake correctly, they cannot outbrake me from an inner line. Their driving is based on the same laws of physics as mine. As long as I don't screw up, I really don't have to worry about it, unless the guy behind me is significantly faster.

Quote:
Jumping off the throttle and slamming the brakes is a commonality because it induces a trail-braking over steer situation: Under throttle, the front end of the car will rise if only a small amount, and the back end will sink by a small amount. When the throttle is cut, the front drops and the rear rises, slamming on the brake hard will further the front end drop and rear end rise. Which, in terms of chassis dynamics will cause down force to lift off the rear end (actually, it is weight transferring forward via momentum, but to make it easier to understand, you can call it a loss of down force if ya like.)
I don't understand what you mean by "a trail-braking oversteer situation". Calling grip downforce doesn't really make things easier to understand, quite on the contrary.

Quote:
Basically, if the guy behind you has the horsepower, he'll pass you eventually no matter how hard you try to hold him off. The general rule of thumb for me is that if he is a half mile behind and then becomes a half car length behind me while I am making a perfect run, he's already shown me he has the horses and I am not going to be able to hold off the onslaught and might as well allow him by to avoid an accident. And, just because he has outrun me doesn't mean I am not longer a problem for him! Generally unless there is a major difference in performance, I can at least keep up and hope to capitalize on his every mistake.
Overtaking is not always about more horsepower. I myself usually drive the Maserati and I've had plenty of situations in which I'm under pressure from a Saleen behind me. They have more torque so they can easily catch me down the straights and may even get beside me for the braking. But since I'm on the outer lane with better brakes, I don't have anything to worry about once I get over the psychological problem.

Letting someone overtake you just because they've catched up with you is silly. If you can keep up with them after overtaking, why would you want to let them pass you? I personally find driving behind someone a lot harder than driving in front of someone, because behind someone you can't see your brake point and you can't know when the guy in front of you will start braking. Brake testing and all that... It's consuming to keep up close.

Quote:
A much better option is to try and out-corner an opponent as opposed to out-braking him. If you think you can hold him off, take the choice line and block a little. Know your vehicle and use its advantages to your benefit, if you've got a car that corners like a bread truck, but accelerates like a rocket, then maybe you can allow the opponent up beside you, but then outrun him down the straights? If cornering is superior to acceleration, maybe you could block down the straights?

In the very end, driving deliberately and hitting your marks carefully and smoothly will get you better lap times than changing your style just because somebody is putting pressure on you.
Braking is a part of the cornering process. Of course you are always trying to outcorner your opponents, that's what track racing is all about. Without corners it would be quite an easy sport. Optimal cornering involves optimal braking. That is why outbraking is important.

Blocking is unsportsmanlike. It is also in most cases completely unnecessary. It will also ruin your laptimes, so you are just digging your own grave. Usually the best option under pressure is to drive normally, without blocking.
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Unread 28 March 08, 12:08   #45
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It's a common psychological problem. While entering the braking you fear that the guy behind you will outbrake you. The most common form of this problem is fearing that you will brake too early. The result is that you miss the brake point and thus enter the corner too fast, miss the apex and leave a hole for the overtaker.
An even more common problem is that the guy behind you thinks he CAN outbrake you without having studied your driving/braking behaviour and therefore does not recognize the proper opportunity to try and outbrake you, or he thinks he still can outbrake you while you're already turning into the corner. Result: you get shoved off the track. This happened to me again and again, because there are only very few people who know how to race properly (especially on public servers).

This fuels and confirms the fear and makes you brake too late. Only when you know your fellow racers, you can get out of this situation.

PS I don't want to derail this discussion into discussing driving behaviour. I agree that hitting the right brake markers while under pressure is part of the sport's psychology.

Last edited by redi; 28 March 08 at 12:33.
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Unread 1 April 08, 14:51   #46
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Any of this help a guy like me who uses a keyboard? I just "hold er down" then hit the brakes and slide/spin/curse then point at the next corner and pull the trigger.:p
Maybe that's why I like the bigger/heavier US cars?

Seriously, besides setting up the suspension and front/rear bias, is there much more I can do on the keyboard?

(I won't even go into the on/off lurching in the corners, as I tap the keys to turn)
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Unread 1 April 08, 15:10   #47
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Any of this help a guy like me who uses a keyboard? I just "hold er down" then hit the brakes and slide/spin/curse then point at the next corner and pull the trigger.:p
Maybe that's why I like the bigger/heavier US cars?

Seriously, besides setting up the suspension and front/rear bias, is there much more I can do on the keyboard?

(I won't even go into the on/off lurching in the corners, as I tap the keys to turn)
Trying to drive with your keyboard is hopeless. I would seriously recommend that you invest a few hundred bucks for a Logitech G25R wheel and pedals. It's definately worth the money and brings the game to a whole new level.

But to answer your question, I have no idea how to set up a car for keyboard controls.
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Unread 1 April 08, 15:29   #48
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Any of this help a guy like me who uses a keyboard? I just "hold er down" then hit the brakes and slide/spin/curse then point at the next corner and pull the trigger.:p
Maybe that's why I like the bigger/heavier US cars?

Seriously, besides setting up the suspension and front/rear bias, is there much more I can do on the keyboard?

(I won't even go into the on/off lurching in the corners, as I tap the keys to turn)

A bad habit i had when playing with keyboard was that put the camber to the maximum ,it is more stable in corners and with keyboard you feel it. My solution :roflmao: i bought a shity steering wheel for 35 hahaha, it has only 180 degrees calibration but hey, it works fine and i bought what i paid for .
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Unread 1 April 08, 22:59   #49
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Anyway, back to the topic. Braking, that is.
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Unread 7 April 08, 11:13   #50
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got a new one for you doo, what about wet races, what would be the best policy to stop the slided off track even you know it a fast corner.many trys i know it to do with the speed ,but how would you judge the correct speed/brake for it.

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