[Handling guys] Can brakes lead to less rear traction?
07-20-2015, 11:37 AM
#1
[Handling guys] Can brakes lead to less rear traction?
I had some new goodies for yesterday's AutoX and the back of my car was a lot more lively that usual. I was able to actually maintain a slide and bring it back (I usually don't have enough power to do that). And I went on to gather more oversteer before snapping back and going all the way around.
The brakes were the only change. Before it was all stock with only HP+ pads in the front (heavy front bias configuration). Now I have Quietslot rotors (I know) and HP+ pads front and rear. This would effectively move my braking bias towards the rear.
Could added rear braking bias contribute to reduced rear traction overall?
The brakes were the only change. Before it was all stock with only HP+ pads in the front (heavy front bias configuration). Now I have Quietslot rotors (I know) and HP+ pads front and rear. This would effectively move my braking bias towards the rear.
Could added rear braking bias contribute to reduced rear traction overall?
07-20-2015, 11:39 AM
#2
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Fully bedded in? How long have you had the new rears on the car. Yes, I do think that could cause you to go around, especially if you're not used to the new bias.
07-20-2015, 11:59 AM
#3
I installed them on Friday and did some quick bedding. Brakes seemed to work and felt good to me.
The thing that got me with the new stuff. I was actually able to lock the wheels and get to ABS. I wasn't able to do that before.
But rearward bias contributing to overall lack of rear grip? The theory isn't that far out there to me. But it's pretty far out.
The thing that got me with the new stuff. I was actually able to lock the wheels and get to ABS. I wasn't able to do that before.
But rearward bias contributing to overall lack of rear grip? The theory isn't that far out there to me. But it's pretty far out.
07-20-2015, 12:13 PM
#4
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That is interesting. To me, what you are describing sounds like an increase in front bias. It seems like the front rotor swap may have gained you front bias, leading to an unweighting/ unsettling of the rears. This unweighting may lead to a more "lively" rear end.
Dunno... Jm2c! :-)
Dunno... Jm2c! :-)
07-20-2015, 12:25 PM
#5
That's what I had before. I have a few shots of my car under braking and it looked like it was doing an endo.
With the rears doing more to slow the car, the tires are catching more heat and being brought closer to overheating. When it comes time to turn, with the rears already near the threshold, it's easier to push them past it.
At least that's my reasoning.
Another reasoning is the fresh tires. Same spec as the old tires. Just newer. The old tires would have been more likely to understeer (Which they did do). The new tires would be the opposite.
With the rears doing more to slow the car, the tires are catching more heat and being brought closer to overheating. When it comes time to turn, with the rears already near the threshold, it's easier to push them past it.
At least that's my reasoning.
Another reasoning is the fresh tires. Same spec as the old tires. Just newer. The old tires would have been more likely to understeer (Which they did do). The new tires would be the opposite.
07-20-2015, 01:16 PM
#6
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I had similar result in a different car. It was a FWD. It came front disk rear drum and i did a rear disk conversion but did not change out the proportion valves on the Master Cyl. This results in a more active rear braking system coupled with disk brakes (better grab) i was able to make the *** pitch our when cornering depending on how i applied the brakes going into the corner (late hard braking) then when i went to a beefier rear bar and stiffened up the Koni's, the *** end really liked to step out more when i would corner, let off gas, brake and back on gas. was an interesting experience the first few times it occurred as i was not expecting those results.
07-20-2015, 02:56 PM
#9
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I dont think you could warm up your tires in one AutoX run, much less overheat them to the point of losing ONLY rear traction. Depending on how new the tires are, I would bet that the likeliest reason for this behaviour is the coating that is applied to new tires to preserve them for storage/shipping.
07-20-2015, 03:38 PM
#11
They're not that new. Some 4000 miles on them, the mold release is gone.
Dunlops have been know to have low operating temperature range. One of the reasons I chose them. I have overheated other sets of ZIIs in the past. Low traction and the tires turned purple. I now spray them with water between runs.
Dunlops have been know to have low operating temperature range. One of the reasons I chose them. I have overheated other sets of ZIIs in the past. Low traction and the tires turned purple. I now spray them with water between runs.
07-20-2015, 04:31 PM
#14
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If you are trailbraking and it's at this point this is happening, yes.
If you are done braking, and now it's all gas on/off etc, then no.
What would make the rear loose is brake force being applied, and locking the unloaded rears. Or having more front bias which would transfer more weight to the front, unloading the back which makes the rear loose.
If this is on throttle controlled, like, more gas more step out, I dunno man. Brakes aren't a factor here.
My vote would be great stopping power upfront, more shift of weight to the front = even less load on the rear than before and therefore easier to step out.
Oh, and you are getting snapoversteer?! Get on the gas sooner. Stop that.
If you are done braking, and now it's all gas on/off etc, then no.
What would make the rear loose is brake force being applied, and locking the unloaded rears. Or having more front bias which would transfer more weight to the front, unloading the back which makes the rear loose.
If this is on throttle controlled, like, more gas more step out, I dunno man. Brakes aren't a factor here.
My vote would be great stopping power upfront, more shift of weight to the front = even less load on the rear than before and therefore easier to step out.
Oh, and you are getting snapoversteer?! Get on the gas sooner. Stop that.
