pad knockback
#1
pad knockback
Well, I ran my first event with my new front Stoptech BBK, and experienced pad knockback at every long sweeper. I just read a bit about this phenomenon in the stoptech website, and just wanted to find out whether all of you track regulars are experiencing this as well.
It's a bummer because I never experienced it on the stock single piston brakes. Now, I have to tap my brake once or twice before my next braking zone.
How about you folks with the oem brembos or other BBK models? Are you guys and gals experiencing pad knockback? If it's happening with the Stoptech's, it should be happening to every brake system out there.
It's a bummer because I never experienced it on the stock single piston brakes. Now, I have to tap my brake once or twice before my next braking zone.
How about you folks with the oem brembos or other BBK models? Are you guys and gals experiencing pad knockback? If it's happening with the Stoptech's, it should be happening to every brake system out there.
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6 pot front 4 pot rear by 350zbrakes
This kit uses Wilwood sl6 front and I find no pad kick back. I can hammer the brakes at 125 and slow to 45. It is great.
sorry to hear of your problem. Does Stoptech offer a fix?
sorry to hear of your problem. Does Stoptech offer a fix?
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Sucks don't it??
Pad knockback is pretty common with the Track Brembo brakes as well. I think there is a whitepaper on Stoptech's website on some solutions...you found one of them..left foot tap(s) to bring your pistons to your pads and pads to your rotors. Another option, they make springs that go behind your pistons to make sure they keep the pads against the rotors...however, this creates drag and will wear your pads down quickly.
I find the left foot tap works well and especially down long staights, it's good to make sure the brakes are still home anyway
I find the left foot tap works well and especially down long staights, it's good to make sure the brakes are still home anyway
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After doing StopTech's 13" kit up front, this is really my only significant complaint (although better description/pictures of the brake hose routing would help).
My concern is what this actually means - ie, the reason this is happening is because there is something flexing under the lateral loads the car is generating. My real concern is this is happening with Falken Azenis. I can only imagine with R-compounds and bigger rubber how much worse this is going to get. And will something finally 'give'. Makes me nervous.
ahm
My concern is what this actually means - ie, the reason this is happening is because there is something flexing under the lateral loads the car is generating. My real concern is this is happening with Falken Azenis. I can only imagine with R-compounds and bigger rubber how much worse this is going to get. And will something finally 'give'. Makes me nervous.
ahm
#5
Originally posted by amolaver
After doing StopTech's 13" kit up front, this is really my only significant complaint (although better description/pictures of the brake hose routing would help).
My concern is what this actually means - ie, the reason this is happening is because there is something flexing under the lateral loads the car is generating. My real concern is this is happening with Falken Azenis. I can only imagine with R-compounds and bigger rubber how much worse this is going to get. And will something finally 'give'. Makes me nervous.
ahm
After doing StopTech's 13" kit up front, this is really my only significant complaint (although better description/pictures of the brake hose routing would help).
My concern is what this actually means - ie, the reason this is happening is because there is something flexing under the lateral loads the car is generating. My real concern is this is happening with Falken Azenis. I can only imagine with R-compounds and bigger rubber how much worse this is going to get. And will something finally 'give'. Makes me nervous.
ahm
I talked to one of the track instructors regarding this issue, and he said that he has run accross a lot of people who have complained about the Z's propensity to flex at the hub. He also said that his Viper doesn't exhibit any significant knockback.
Well, I guess you get what you pay for....Thanks Nissan for using another Altima component!
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Re: 6 pot front 4 pot rear by 350zbrakes
Originally posted by C Ray Z
This kit uses Wilwood sl6 front and I find no pad kick back. I can hammer the brakes at 125 and slow to 45. It is great.
sorry to hear of your problem. Does Stoptech offer a fix?
This kit uses Wilwood sl6 front and I find no pad kick back. I can hammer the brakes at 125 and slow to 45. It is great.
sorry to hear of your problem. Does Stoptech offer a fix?
This is not a Wilwood v. Stoptech v. Brembro issue. The issue is with the hub of the car flexing allowing the rotor to knock back the pads. This is an issue endemic to fixed caliper systems (i.e., all BBK's).
If you have not experienced it -- it is only because you are (a) not putting enough lateral (turning) g-forces on the car to cause it (you will only get it in long sweepers on the track -- very unlikely to see it on the street), or (b) your hubs may not be flexing (that's a good thing).
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I experience this every time, it's nothing to be afraid of. Ever watch those Best Motoring videos? Watch the foot cams, they'll requently show the guys tapping the break pedals on the straights. This is to get the pads back where they belong. This is happening to everyone who tracks their car.
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Originally posted by Blue Liquid
I experience this every time, it's nothing to be afraid of. Ever watch those Best Motoring videos? Watch the foot cams, they'll requently show the guys tapping the break pedals on the straights. This is to get the pads back where they belong. This is happening to everyone who tracks their car.
I experience this every time, it's nothing to be afraid of. Ever watch those Best Motoring videos? Watch the foot cams, they'll requently show the guys tapping the break pedals on the straights. This is to get the pads back where they belong. This is happening to everyone who tracks their car.
I only seem to get it as my pads are wearing down -- and then only mildly. It get used to it and it really does not affect braking power -- only the feel of the pedal.
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Originally posted by dnguyent
I'd have to 2nd that concern. If I'm getting this much pad knockback with street tires, I can't imagine what R-compounds would do.
I talked to one of the track instructors regarding this issue, and he said that he has run accross a lot of people who have complained about the Z's propensity to flex at the hub. He also said that his Viper doesn't exhibit any significant knockback.
Well, I guess you get what you pay for....Thanks Nissan for using another Altima component!
I'd have to 2nd that concern. If I'm getting this much pad knockback with street tires, I can't imagine what R-compounds would do.
I talked to one of the track instructors regarding this issue, and he said that he has run accross a lot of people who have complained about the Z's propensity to flex at the hub. He also said that his Viper doesn't exhibit any significant knockback.
Well, I guess you get what you pay for....Thanks Nissan for using another Altima component!
with the amount of knockback i'm seeing - a trait I never had in my wrx, and i beat the crap out of that car on the track - i am really quite concerned something will let go at a less than opportune moment. not exactly sure when the opportune moment is to have a piece of the suspension fissure, but trail braking into turn one somewhere isn't on my list of possibles.
i guess the more direct question is, has anyone actually had a part of the suspension cease to be whole in operation?
ahm
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I've discussed this with a number of you on the phone, email, and in person. My engineering team is working on a universal fix. At this point however, it's just something that we Z folk will have to deal with. Another poplular platform that has the same problem is the Subaru WRX. Actually, it's a bit worse on that car. The 300ZX was also significantly worse than the 350.
Don't worry guys, I'll keep you updated on any progress in this area. I drive my car on the track all the time, so I'm well aware of the issue. It's not quite as bad on the 332mm kit as it is on the 355mm kit, but it will still sneak up on you if you don't keep it in mind after a series of S turns or sweepers.
As for the entire suspension failing...I wouldn't worry about that. It does flex, but I don't think we need to worry about anything letting go.
Don't worry guys, I'll keep you updated on any progress in this area. I drive my car on the track all the time, so I'm well aware of the issue. It's not quite as bad on the 332mm kit as it is on the 355mm kit, but it will still sneak up on you if you don't keep it in mind after a series of S turns or sweepers.
As for the entire suspension failing...I wouldn't worry about that. It does flex, but I don't think we need to worry about anything letting go.
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I spoke to jritt over the phone earlier this week. Thanks for taking the time to explain it. Now that I know what it is, I am less worried about it.
One thing he mentioned is that the race teams blueprint their hubs. Not an option for us common folk.
One thing he mentioned is that the race teams blueprint their hubs. Not an option for us common folk.
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Originally posted by J Ritt
I've discussed this with a number of you on the phone, email, and in person. My engineering team is working on a universal fix. At this point however, it's just something that we Z folk will have to deal with. Another poplular platform that has the same problem is the Subaru WRX. Actually, it's a bit worse on that car. The 300ZX was also significantly worse than the 350.
I've discussed this with a number of you on the phone, email, and in person. My engineering team is working on a universal fix. At this point however, it's just something that we Z folk will have to deal with. Another poplular platform that has the same problem is the Subaru WRX. Actually, it's a bit worse on that car. The 300ZX was also significantly worse than the 350.
Originally posted by J Ritt
<SNIP>
As for the entire suspension failing...I wouldn't worry about that. It does flex, but I don't think we need to worry about anything letting go.
<SNIP>
As for the entire suspension failing...I wouldn't worry about that. It does flex, but I don't think we need to worry about anything letting go.
ahm
#13
Stock sliding calipers will not exhibit the pad knockback concern--only on fixed caliper applications, as Skrill and JRitt have explained.
The WRX application to which Jeff was referring was the Stoptech BBK, not the OE setup. Both Skrill and JRitt both have significant track experience, both of which experience this pad knockback. I too notice it on my car, even with the stock Brembos. Pad knockback is apparent even in R32 Skylines--NOT a car created with Altima components, as you indicate.
The WRX application to which Jeff was referring was the Stoptech BBK, not the OE setup. Both Skrill and JRitt both have significant track experience, both of which experience this pad knockback. I too notice it on my car, even with the stock Brembos. Pad knockback is apparent even in R32 Skylines--NOT a car created with Altima components, as you indicate.
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i have the knockback problem on my stock brembo's, due the my 20" low profile tire setup. there is no give in the tire since the sidewall is so stiff, which increases the moment on the hubs. i just use the "tap" method, and everything seems to work out fine.
in fact, i seem to "tap" on every car that i drive, just out of habit. so i guess once you get used to doing it, it's just routine.
Chad
in fact, i seem to "tap" on every car that i drive, just out of habit. so i guess once you get used to doing it, it's just routine.
Chad
#15
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First, I know this thread is as old as the internet.
I see that it just drops dead with no fix.
It seems these are the only options but I can't find anyone using them. . . besides #1
1. Left foot tap to set brakes.
2. Brake Knock Back Springs behind the pistons
3. Wilwood brake knock back check valve
Is this a dead topic? Or has anyone used #2 or #3?
I see that it just drops dead with no fix.
It seems these are the only options but I can't find anyone using them. . . besides #1
1. Left foot tap to set brakes.
2. Brake Knock Back Springs behind the pistons
3. Wilwood brake knock back check valve
Is this a dead topic? Or has anyone used #2 or #3?
#18
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Franken, I suggest you google the topic and it is universal, not just 350z specific.
There are even some other decent threads on this site.
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