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Old 09-01-2009, 04:19 AM   #16
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Quote:
Originally Posted by Lonestar View Post
rally cars turn in hairpins by using the handbrake

Paul
it is actually a combo of foot braking, hand braking, engine braking, throttling, steering and racing line....
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Old 09-01-2009, 04:23 AM   #17
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Quote:
Originally Posted by ganymede View Post
it is actually a combo of foot braking, hand braking, engine braking, throttling, steering and racing line....
you forgot to mention "guts" in there

what I meant is not all 1:1 racecars have "clean" racing line where the rear-end slip angles are kept to a minimum... rally cars often yaw around their front wheels

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Old 09-01-2009, 08:56 AM   #18
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I'm reading %'s when setting brake bias on offroad buggies and truggies on the thread. Ex: 30/70, 40/60, 50/50, etc

How are you calculating the %?
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Old 09-01-2009, 10:34 AM   #19
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Quote:
Originally Posted by Lonestar View Post
I think he got it 100% right
I know I did. The "which part?" was sarcastic. Though there was a moment after his post saying I got it backwards where I wondered if I had violated the laws of physics and would have the wrath of RC-racing math nerds fall on me.

Quote:
Originally Posted by san. View Post
I'm reading %'s when setting brake bias on offroad buggies and truggies on the thread. Ex: 30/70, 40/60, 50/50, etc

How are you calculating the %?
Since we're in the Nitro off-road forum and not electric (where you can actually set as a %age depending on your ESC), it's a complicated mathematical method called "eyeballing it" AKA pulling numbers out of our ass.

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Old 09-01-2009, 10:35 AM   #20
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People are just guesstimating it.

Amoeba: I mean, if someone sets the brakes 50/50, and they lock up, but not very strongly when pushing it forward, it is possible, that under braking as the front wheels are loaded more, they will start turning abit, but the rear wheels will stay locked as there is less weight on them -> front wheels turning, rear wheels locked, bias towards the rear. I assume this is what you were explaining.

However. I always set my brakes on the bench, and make sure they feel good on the track. Front wheels roll, but clearly are braking, rear wheels lock.
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Old 09-01-2009, 10:44 AM   #21
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Originally Posted by JQ View Post
People are just guesstimating it.

Amoeba: I mean, if someone sets the breaks 50/50, and they lock up, but not very strongly when pushing it forward. It is possible, that under braking as the front wheels are loaded more, they will start turning abit, but the rear wheels will stay locked as there is less wheight on them -> front wheels turning, rear wheels locked, bias towards the rear. I assume this is what you were explaining.
Ah, thanks for your clarification JQ. That is what I was explaining, though in more absolute terms.
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Old 09-01-2009, 12:04 PM   #22
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I'm not real sure why you want more front bias at anytime on a 1/8 buggy or truggy. If at any time the front wheels lock up you slide and lose all steering. You can also land jumps, hit the brakes and flip over. I realize real cars may have more front, they also have much more weight transfer, weight over the wheels, etc...

same does not apply for our little cars in the same sense..

You want to use as much front brake as possible without locking your front tires.

Generally that will be approx 30% front and rear 70%, the % is just a general feel. However, I use that method and use a low epa setting on my losi 2.0 b. Maybe 35-45 percent of travel on the epa. I try not to "lock" the wheels when breaking.

If you figure this out your car will stop faster, smoother, and be in more control.

I'll try to find some video to validate this point...
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Old 09-01-2009, 12:05 PM   #23
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adam drake has a great you tube video on how to set up brakes properly...
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Old 09-01-2009, 01:54 PM   #24
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i used to drive with mostly rear brakes, since i went to front bias i have gotten faster. with too much rear brakes i loose the back end sometimes coming into a 180. i like to brake early, turn and blip, then power out, easiest way around a tight turn. the faster i blip the wider the turn, the slower i blip i turn sharper.
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Old 09-01-2009, 02:24 PM   #25
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I agree w/ Jblaze, better driving lines w/ greater front bias.

I found out by accident that this works for me...I got to the track late, threw my engine in, hooked up the linkages w/o purposely setting bias, and went out for qualifiers. The end of our front straight (www.Trax70.com) is a 180 degree rh hairpin turn. With my previous rear bias setup I'd come as fast and hard as possible, slam the brakes to make my rear loose, begin to turn and slide around the corner, then on the gas as soon as possible. I found that I could get it right sometimes, but if I didn't I'd get a horrible on-power push and end up wide.

W the front bias setup I am actually slowing down alot quicker, letting me stay on the gas longer on the straight before starting to turn. When I do start to turn, all of the weight is on my front tires and she turns in super quick. I coast thru the turn, am around the hairpin, and back on the gas hard w/ my wheels pointing straight to the step up jumps ahead. I run an AE RC8 w/ a slightly changed 'worlds' setup

Now that I've got it setup this way I'm way faster around the track w/ my buggy. I won the buggy Amain by 2 laps w/ this setup and I was always slower in buggy than in truggy.

It's funny because I ride motorcycles (Honda VFR800FI) and this is how we're taught to turn and on a bike at least 70% of braking power comes from the front tire.
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Old 09-01-2009, 03:01 PM   #26
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http://www.youtube.com/watch?v=P6WHGXq5nfA
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Old 09-01-2009, 03:29 PM   #27
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Default adam drake how to video....

http://www.youtube.com/watch?v=P6WHGXq5nfA



More front brakes or front brake bias is never the way to go guys. I'm not knocking it by any means but I have tried it years and years ago.

On the same point...

If you got way to much rear and no front you have improperly set brakes, you hit the brakes and spin out. You can also have to much front, not enough rear and it picks up the rear and pushes it around, you can slide the tires and push, etc...

This video should help you guys get it straight and ready to rock!

Good luck!
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Old 09-01-2009, 05:26 PM   #28
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I know of near 90% of the time both Ryan Lutz and I ran rear brake only (0/100%) with the STRR.....

My current buggy set up is somewhere around 60/40 as front brakes still slow the car down much faster with weight transfer.


As Alan pointed out though, set them up lightly as to never let them lock up.

One thing I do (and maybe some of you do) is when track conditions change say wet to dry, you reach for the epa settings on the brake side and dial them out until they don't lock up.



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Old 09-01-2009, 05:34 PM   #29
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And for you rally guys, the bias on our car was set 40/60 and I never touched the hand brake unless we came across a "1R->" or "1L->"

Left foot always controlled the attitude of the chassis and how much the steering input vs. slip angle was required to keep the quarter panel off of a tree or embankment.
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Old 09-01-2009, 05:42 PM   #30
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Just to clarify about full size car brake bias, pavement cars almost always run more bias towards the front. This is because the high speeds and high grip levels combined with really hard braking leads to a massive amount of weight transfer to the front. Plus locking the rears on pavement usually means a spin.

Dirt is a different animal. Most dirt oval cars run much more rear brake. I don't have any experience with full sized offroad vehicles but I suspect they do too. There are a few reasons for this.

1. Dirt means slower speeds, less grip and less braking force. This means less weight gets transfered to the front tires so they will not be able to handle as much brake force.

2. Forward bite being very important on dirt cars leads to them having much more weight biased to the rear. The front of the car tends to be very light, again meaning less brake force available at the front.

3. Dirt oval cars may look very "loose" sliding sideways through the corner but they actually tend to not want to turn into the corner. A quick stab of the brakes with a lot of rear bias helps the car rotate into the corner. Rally drivers do the same thing by yanking on the handbrake.

So in conclusion, I think at least a slight rear bias would be preferable on our cars. I am not sure 0 front is the way to go but if it works for you, do it. If the car is too twitchy entering a corner on the brakes, move it forward. If it wont turn in on the brakes, move it back.
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Last edited by wingracer; 09-01-2009 at 06:58 PM.
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