rec.autos.simulators

GPL: Braking Question on Preventing Tire Lock Ups

Joe Sha

GPL: Braking Question on Preventing Tire Lock Ups

by Joe Sha » Mon, 28 Feb 2000 04:00:00

While I'm certainly no expert in GPL (just ask the gang in my league), a couple
of thoughts occur.

1.  Are you using the stock LWFF pedals? If so that could be part of the
problem. They have notoriously soft pedals and I found them almost unusable.
Some have had success by using stiffer springs, I finally bought CH Pedals and
re-wried them into the LWFF system and that helped a LOT. I also rigged up a
"stop" from a *** door stop that prevents me from braking into the lock up
zone. It's soft enough that I can still lay *** if I need to but it gives me
the ability to slam on the brakes and not lock up. Others recommend using a
racketball ball.

2.  Mess around with the brake bias. I'm so bad at creating setups I hesitate to
suggest changes but that can make a big difference.

3.  Realize that some marques just flat brake better than others. Ferraris are
better than Eagles for example. I'm sure there's a technical reason for this but
I don't know it :-)

4.  While looking at the AI can be helpful, it's MUCH more helpful to look at
real people. Download any of the hot laps for your marque that are on many sites
around the web. Then get a good replay utility, GPL Spy Girl or GPL Replay
Analyzer and put one of your replays up against one of theirs. It really shows
the difference between lines and braking points.

5. Finally, the suggestion about practice is all too true. This is a game that
requires a lot of track time.

Good Luck,
Joe


> I've been driving GPL 1.2 for about a week now. I chose the Lotus and
> Watkins Glen to learn. I also have a Logitech FF steering wheel. I have
> noticed that the AI cars can brake much quicker than me and they don't lock
> their tires like I do. I have tried to get into situations with the AI cars
> in which we are neck and neck going into Turn 4, the one the goes over the
> rise then turns right. The AI cars declerate much faster and they don't lock
> their brakes. I end up having to start braking earlier to prevent lockup and
> the AI cars go by me like I'm standing still. I turned down the sensitivity
> of the brake in the Logitech profiler and I make sure I'm wearing only socks
> so I can feel the brake pedal better. I don't expect the beat the AI cars I
> just want to be able to brake a little better. Although I'm still
> inconsistent (I can't hold myself back sometimes) my best lap at WG is 1:11.
> I can't do it all the time but if I could get this braking stuff figured out
> maybe I could. Any braking tips would be appreciated. Thanks.

> Kelvin

Matthew V. Jessic

GPL: Braking Question on Preventing Tire Lock Ups

by Matthew V. Jessic » Mon, 28 Feb 2000 04:00:00

To practice braking, I'd suggest finding a course with long
straights with flat braking zones and good reference points.
Monza is good on the front straight and the straight before
the Lesmos and Parabolica.

You can try braking several times down the long front straight
and then do the Lesmos and Parabolica realistically. The point of
going around the circuit rather than resetting is to have warm
tires as someone else mentioned.

As you get good at it, then to get the ultimate
braking capability, adjust your brake bias so that
more force is being used at the rear tires,
but not enough to lock the rear tires first. It will be
obvious when you go too far as you will spin. ;)
Once you have the skill to brake hard, the difference in
braking power between a near optimum setup and a overly
safe brake bias setup is noticible.

Be aware also that this should probably be tested and set for
the end of race light fuel load condition where the weight on the
rear tires is lightest and they are the easiest to lock.
If you set it up for a full fuel load, you might find the rears locking
first sometime during the race as you burn off fuel.

Once you are set up so that you don't have to worry about the
rears locking under braking (in normal situations), you can
practice hard braking and learn to concentrate on the front tires,
learning to "threshold brake" them (getting maximum force).

Be aware of terrain undulations that can unload the tires.
If you try to brake when the car is light on the tires (such
as going over a crest), you might lock the tires anyway.

If you don't have the car in good shape approaching a corner,
it is safer to brake earlier and start lighter until the car is settled.
(If the car is still rotating as you approach the braking zone,
say because you completed a pass a little too late,
or you put a wheel off the track, and are still correcting
for it, etc.)  If you feel you have to lock the fronts
because you got too deep into the braking
zone too fast, then you are likely to slide off the corner
since locked tires or releasing the brakes breifly to
unlock and reestablish threshold braking will both result in
slower speed loss than when not locking a tire.

--
Matthew V. Jessick         Motorsims

Vehicle Dynamics Engineer  (972)910-8866 Ext.125, Fax: (972)910-8216

Cossi

GPL: Braking Question on Preventing Tire Lock Ups

by Cossi » Mon, 28 Feb 2000 04:00:00

I personally prefer to lock up the brakes, especially there isn't tire wear
in GPL. I find that locking them suckers up make the car more stable. If I
don't lock them up, car tends to want to fishtail. But this is not a method
you want to use, just look at my lap time. it shows. hehehe

In article


J

GPL: Braking Question on Preventing Tire Lock Ups

by J » Wed, 01 Mar 2000 04:00:00

3 choices:
Switch on brake help - just kidding
learn to modulate (sp?) the brake
put a doorstop into your pedals (have a look at my page)

Jens



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Classic cars, esp. Morris Minor

Rafe McAulif

GPL: Braking Question on Preventing Tire Lock Ups

by Rafe McAulif » Sun, 12 Mar 2000 04:00:00


>I personally prefer to lock up the brakes, especially there isn't tire wear
>in GPL. I find that locking them suckers up make the car more stable. If I
>don't lock them up, car tends to want to fishtail. But this is not a method
>you want to use, just look at my lap time. it shows. hehehe

If you lock all 4, then the car will just go straight ahead and feel
more stable. You are probably locking the rears first, or changing
down too soon, or both, that is why less lockup makes you want to
fishtail. The temp that the tyres will reach though will make them
pretty useless very quickly.

You should be braking just enough so that the squealing is only just
heard, without locking. For more stability, you should only change
down once you have slowed the car by a long way, and make sure the
fronts lock first. F10 view is good for this. Set the balance to 57%
or even 58% to make sure the fronts lock first. Once you have your
braking down pat, move the balance back just a little to get a little
more.

Rafe Mc


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