Fine Tuning Rear Brake Bias
06-04-2009, 11:39 PM
#76
Rennlist Member
I found the best time to tune street brake bias in the rain on a constant radius corner and a straight. Brake at different levels with different bias'. It is fun and you will develop a good sense of what works and what is downright scary..quickly.
06-04-2009, 11:52 PM
#78
06-05-2009, 09:02 AM
#79
Rennlist Member
Good article.
As you corrected yourself and Wolf must be shaking his head in embarrasment, the article says:
"Contrary to what you may be inclined to believe, the amount of weight transfer is not altered by springs, shocks, anti-roll bars, etc. Weight transfer is a result of inertia and momentum. These suspension components cannot change that. What these components can do is impact how much the suspension moves in response to the load change, and how quickly the load transfers to the tire contact patches."
This all goes back to driver style, input, and compliance. Weight transfer rate is certainly assisted by sprngs and shocks. That has not been in question.
Again, many factors.
Mk
As you corrected yourself and Wolf must be shaking his head in embarrasment, the article says:
"Contrary to what you may be inclined to believe, the amount of weight transfer is not altered by springs, shocks, anti-roll bars, etc. Weight transfer is a result of inertia and momentum. These suspension components cannot change that. What these components can do is impact how much the suspension moves in response to the load change, and how quickly the load transfers to the tire contact patches."
This all goes back to driver style, input, and compliance. Weight transfer rate is certainly assisted by sprngs and shocks. That has not been in question.
Again, many factors.
Mk
Last edited by 333pg333; 06-05-2009 at 09:30 AM.
06-05-2009, 09:39 AM
#81
Rennlist Member
Hey I might be simply misreading this and going under the pretext of "Well it sure feels like..."
Also thanks for the charts. Very interesting. On a lesser note (by a million percent) I left foot brake probably 80% of the time in my Auto dd beater. Great practice, but hard to translate onto the track except for small touches just to bring the tail around on corners where you've already changed gears.
Here's a good video showing some deft footwork.
http://www.youtube.com/watch?v=azpqT...eature=related
Also thanks for the charts. Very interesting. On a lesser note (by a million percent) I left foot brake probably 80% of the time in my Auto dd beater. Great practice, but hard to translate onto the track except for small touches just to bring the tail around on corners where you've already changed gears.
Here's a good video showing some deft footwork.
http://www.youtube.com/watch?v=azpqT...eature=related
06-05-2009, 11:42 AM
#82
Rennlist Member
Let me see If I understand the extreme condition.
so you alter the spring and shocks and what happens with the same stopping force. (force of tires on the ground I imagine).
yes, the body dives up front, lifts in the rear, so Cg height goes up as the body rotates around the front wheel. So, for the same deceleration rate you would have more weight transfer. If you were at the limit before, g's of deceleration capabiltiy would go down.
so you alter the spring and shocks and what happens with the same stopping force. (force of tires on the ground I imagine).
yes, the body dives up front, lifts in the rear, so Cg height goes up as the body rotates around the front wheel. So, for the same deceleration rate you would have more weight transfer. If you were at the limit before, g's of deceleration capabiltiy would go down.
...except surely if you have 1000lb/in springs with commensurately valved shocks and hit the brakes with 'x' force from eg 100 mph v's just change your springs to 100lb/in and soft shocks then wouldn't the same 'x' stopping force from 100mph allow more forward tilt due to less resistance from the suspension? I get that the car has the same CofG etc so it can only be what it will be, but there must be changes that can be made to componentry that would give different reactions under the same stopping conditions, no?
06-05-2009, 11:44 AM
#83
Rennlist Member
06-05-2009, 12:20 PM
#84
Not the sharpest tool in the shed
Rennlist Member
Rennlist Member
Here's a good video showing some deft footwork.
http://www.youtube.com/watch?v=azpqT...eature=related
http://www.youtube.com/watch?v=azpqT...eature=related
06-05-2009, 12:52 PM
#85
Rennlist Member
06-05-2009, 05:13 PM
#86
Rennlist Member
Haha, well he was back with them by the bottom corner. What amazes me is having driven that track many times, just how smooth the film looks over the gators. I know that this is not what you feel in the car.
06-05-2009, 06:22 PM
#87
Rennlist Member
Now that is what suspension is for!!!
Have you seen my in car? the gators shake my car to death! It actually unplugged my ECU a few years ago. Some day, MOTONS!! yeah right!
mk
Have you seen my in car? the gators shake my car to death! It actually unplugged my ECU a few years ago. Some day, MOTONS!! yeah right!
mk
06-05-2009, 10:39 PM
#88
Road Warrior
Rennlist Member
Rennlist Member
cool thread. I put the 55 bar valve in 2 yrs ago, really seemed to help straightline braking and it felt like it made the transition w/trail braking easier/sooner too.
it also increased the steering sensitivity under threshold braking. any wiggling can send you into a slide in a flash. quite useful as long as you are aware/used to it.
an adjustable unit would be very cool though.
it also increased the steering sensitivity under threshold braking. any wiggling can send you into a slide in a flash. quite useful as long as you are aware/used to it.
an adjustable unit would be very cool though.
06-05-2009, 11:06 PM
#89
Rennlist Member
I just watched my race 1 of the Thunderhill races a couple of weeks ago. you can see my trail braking into 14 was pretty tricky with the rear stepping out a bit on the first 2 laps. after that, It was fine. I think any more, it would be a problem.
you can do a test. remove your rotors, put the calipers back on with an old brake pad in between to act as a false disc. put back on the wheels and tires and go for a drive and see how much braking force the rear has..
Im going to try it this weekend.
mk
you can do a test. remove your rotors, put the calipers back on with an old brake pad in between to act as a false disc. put back on the wheels and tires and go for a drive and see how much braking force the rear has.
.Im going to try it this weekend.
mk
cool thread. I put the 55 bar valve in 2 yrs ago, really seemed to help straightline braking and it felt like it made the transition w/trail braking easier/sooner too.
it also increased the steering sensitivity under threshold braking. any wiggling can send you into a slide in a flash. quite useful as long as you are aware/used to it.
an adjustable unit would be very cool though.
it also increased the steering sensitivity under threshold braking. any wiggling can send you into a slide in a flash. quite useful as long as you are aware/used to it.
an adjustable unit would be very cool though.
