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Old 09-01-2009, 06:00 PM   #31
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yea i could try a little more front brake i have a little bit in the front already no much though i will still roll when i push the brakes ,i have mostly have rear brake it does almost when spin out but thats really only when i almost give it full brake
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Old 09-01-2009, 06:07 PM   #32
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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.



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.

Ah, yes...in my dept. at work, we like to call those the "brown numbers".
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Old 09-01-2009, 06:23 PM   #33
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does brake setup dependent on track as well? if u run on a loose track it probably make more sense with a rear bias... but if u run on a smooth n hard packed dirt track, front bias might be the way to go right?
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Old 09-01-2009, 06:37 PM   #34
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i image that the brakes are depend on the way the track is ,i would think if the the track is loose u proberty whould want more front brake then rear since the track is already loose u just will slide more ,on a smooth track boy im not sure i guess more rear not sure
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Old 09-01-2009, 06:44 PM   #35
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Geez somebody set a standard for what we are talking about here. Some sound like they mean how tight the binders grab & some sound like they mean when one end or the other locks up.Heres the situation I am always in & you can debate what you want to call it. I set my brakes to the traction for that track that day(usually) I set so my fronts are only slowing the car mildly & never "lock up" & if at the end of the straight through the braking bumps under heavy braking the rear rises more than full droop I back off the front brakes.I'll call this medium braking pressure.I then set the rear brakes so there is about a 25% slip angle meaning the rears are not locked up but are spinning about 75% as fast as the ground is going by & some times dial up to above 50-75% slip angle meaning real close to locked up.Now heres where you gotta decide. The fronts dont lock up because they have massivly more traction due to massivly more weight pushing down on them & the rears are close to locked because nothing is keeping them in friction with the ground.Many people call that 30% front & 70% rear & thats fine as long as those people are on the same page as how to get there. On the other hand many people cal that 70% front & 30% rear(wich is closer to the truth)because even though the the front dont lock up it is still being clamped tighter than the rear even though the rear may be lock up. So before I discuss brake bias with people I now try to get a feel for how their brain is picturing 70/30. Its the same as talking rear diff fluid,when some say rear traction out of a turn they mean rear dont get sideways at all & some see it as closer both rear wheels spinning the same amount & pushing the car forward with traction & dont consider the rear getting sideways as loosing traction because its pushing the car forward. So what do you consider when thinking about brake bias?How much the rotors are being clamped or wich wheels are locking up?
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Old 09-01-2009, 06:58 PM   #36
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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.
Just moving my thread to the new page. I think it got lost at the bottom
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Old 09-01-2009, 09:47 PM   #37
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well, here the deal... i hav an old toyota truck with a faulty load sensing valve (brake force proportioning valve) and i disconnected it and the truck ran with almost 50/50 brake bias. the alarming part is that whenever i hav to brake in an emergency situation, the rear will lock up! and on top of that i hav to anticipate braking MILES away... because the braking distance is so much longer vs. a brake system with a proper load sensing valve and brake bias. so, imo a brake with front bias is the way to go for on road car...

back to RC, i wan my ride to hav shortest braking distance possible without any lock up if possible, i brake before entering a corner, blip and power away, i don like to slide my car into the corner and i believe if u drift in a corner u are way too slow...
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Old 09-02-2009, 01:55 AM   #38
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Geez somebody set a standard for what we are talking about here. Some sound like they mean how tight the binders grab & some sound like they mean when one end or the other locks up.Heres the situation I am always in & you can debate what you want to call it. I set my brakes to the traction for that track that day(usually) I set so my fronts are only slowing the car mildly & never "lock up" & if at the end of the straight through the braking bumps under heavy braking the rear rises more than full droop I back off the front brakes.I'll call this medium braking pressure.I then set the rear brakes so there is about a 25% slip angle meaning the rears are not locked up but are spinning about 75% as fast as the ground is going by & some times dial up to above 50-75% slip angle meaning real close to locked up.Now heres where you gotta decide. The fronts dont lock up because they have massivly more traction due to massivly more weight pushing down on them & the rears are close to locked because nothing is keeping them in friction with the ground.Many people call that 30% front & 70% rear & thats fine as long as those people are on the same page as how to get there. On the other hand many people cal that 70% front & 30% rear(wich is closer to the truth)because even though the the front dont lock up it is still being clamped tighter than the rear even though the rear may be lock up. So before I discuss brake bias with people I now try to get a feel for how their brain is picturing 70/30. Its the same as talking rear diff fluid,when some say rear traction out of a turn they mean rear dont get sideways at all & some see it as closer both rear wheels spinning the same amount & pushing the car forward with traction & dont consider the rear getting sideways as loosing traction because its pushing the car forward. So what do you consider when thinking about brake bias?How much the rotors are being clamped or wich wheels are locking up?
I think the only way to move away from track conditions in the measurement (slippery track=> rear wheels lock easier when the rear is offloaded) is to measure how the rotors are clamped and what torque is needed to rotate the front wheels vs. the rear ones with the trigger pushed.

Note that it's very empiric, and variable as well, as if the brake levers have different length, the bias will change as you change the braking EPA's on the radio
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