LegendsRacer - Legends & Bandolero Racing Forum
LEGENDS => Brakes => Topic started by: s10custom on December 22, 2013, 03:05:23 pm
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This past weekend, on asphalt, the car would turn ok but hit the brakes and the would want to kick out and he would have to catch it. One time he didn't catch and it cost us a front clip. Any ideas?
Thanks,
Robert
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Robert,
So where you going with this? Cold, the car starts out ok and then goes south as tires and brakes heat up? Track conditions change? Weather temps change?
Just asking. Those things will change the attitude of the car.
Steve
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add more rear brake.
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You either have to much LF brake or to much rear brake which is causing the rear to kick out on him on entry as your son starts to brake. Adjust the rear shoes away from rear drum to take out rea brake. or plumb a bias valve to take LF brake away to not pull car in to corner.
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Opposite answers...
Scott and Richie, step up to your respective podiums and state your cases please ;D
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I would still like to hear Roberts answer to my questions above.
For the sake of argument, I am going to agree with Richie. My reasoning (and this info from my handling books for pavement cars):
Lets say the car is loose at turn entry. What are the causes and what changes can you make to correct it?
1) There is too much rear brake bias - if oversteer occurs while braking into the turn. To fix, reduce rear brake bias.
2) Too much tire stagger. Reduce tire stagger.
3) Rear roll center may be too high. Lower rear roll center.
4) Right front spring rate too soft.
5) Right rear spring too stiff.
6) Add more cross weight to tighten up the chassis.
7) Right rear tire over inflated.
8) Rear roll steer present in the chassis.
Assuming the that the race car comes to the track with the chassis basically set up properly (front end alignment correct, spring rates correct, weight distribution in the correct range), then there are 5 basic adjustments that can be made at the track to tune the chassis:
1) Tire Pressure
2) Stagger
3) Cross Weight
4) Rear Roll Center Height
5) Front to Rear Brake Proportioning.
Steve
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I have said enough. It works though. If you think about how the brakes work on these cars it will come to you.
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I have said enough. It works though. If you think about how the brakes work on these cars it will come to you.
I do not. Robert is saying his son has a very bad snap loose as soon a brake pressure is applied. Why would you ADD rear brake? that amplifies the already bad entry snap loose.
Please explain to us why adding more rear brake fixes his entry snap loose because this is opposite in any form of racing i know of.
There could be more to it as Freaky said. to high rear roll center, cross, to stiff of RR spring.
If everything is unchanged and issue of snap loose started to present it self with same setup his rear shoe adjusters could be moving on its own adding more rear brake.
I had that issue were my right rear was adjusting more rear brake on its own creating a mess of problems. new springs adjuster etc fixed this issue.
I know when i ran mountain speedway i had way to much rear brake in the car to where i could not enter the corner without my ass wanting to pass me.'
Tooka good bit of rear brake out lowered ear roll and added cross and car was much much more drive able. Still not where i wanted it but at least it was in a race able state now.
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Where am I going with this? I was told one thing by a couple folks and another by some others. I am gathering the data I receive and will make a consensus from that. I'm trying to learn.
Robert
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Scott,
The way I understand the situation; Running pavement; And when brake is applied the rear end is comming around.
I would like to know a bit more about his particular situation and where (exactly) it occurs. That may help to pinpoint the why of his situation.
Steve
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Scott,
The way I understand the situation; Running pavement; And when brake is applied the rear end is comming around.
I would like to know a bit more about his particular situation and where (exactly) it occurs. That may help to pinpoint the why of his situation.
Steve
Agreed, it may not even be a brake problem at all.
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Hi Robert,
Got your message; Thanks for some of the details!
So... If the problem (loose condition) seems to occur in the middle of the turn, you may want to look at:
1) Increase cross weight
2) Decrease stagger
3) Right front spring too soft
4) Right rear spring to stiff
5) Lower rear roll center
6) Right rear tire pressure too high
Since you mentioned the apex of the turn and softer springs in the front, the right front spring rate might be worth looking at.
Steve