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View Full Version : Front wheel chatter during hard braking ?!?



jl2
09-07-2005, 02:16 PM
Hey Everybody,

Has anyone experienced front wheel chatter during hard and semi-hard braking? :?:
It happens at higher RPMs. From 3500 to 5000+, it is noticeable.
3500 and lower it is very slight [if at all].
Also, it is more pronounced during straight line braking, not in a curve.
My car tracks true, so I do not think it is the alignment.
I have not done any suspensions mods.
My brake pads are getting close to the end.
Any ideas?

earlyapex
09-07-2005, 02:31 PM
Does your steering wheel shake a bit? Could be "warped" rotors.

jl2
09-07-2005, 03:15 PM
Yes the steering wheel does shake.
I did think of that.
:cry:
I did not want to think about replacing them.
$$$
How can I verify that?

earlyapex
09-07-2005, 03:55 PM
Yes the steering wheel does shake.
I did think of that.
:cry:
I did not want to think about replacing them.
$$$
How can I verify that?

if the steering wheel is shaking on heavy to medium braking I'm 99.9% sure its the rotors.

jl2
09-07-2005, 04:00 PM
Thanks for the info earlyapex.
:)

jl2

ZK
09-07-2005, 04:58 PM
If you are looking to save money, you can always get the rotors resurfaced. If they aren't too worn down, it should still be within spec. $40 vs $300 for a set of rotors.

Evo442
09-07-2005, 06:31 PM
I'd be willing to bet you that you actually have brake pad material unevenly distributed on the surface of the rotor.

Stoptech has some good technichal info on their site: http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

I have this problem after some track days.

Before you resurface the rotors, try rebedding the pads. This seems to solve the problem for me. Good luck!

earlyapex
09-07-2005, 06:38 PM
I'd be willing to bet you that you actually have brake pad material unevenly distributed on the surface of the rotor.

well, that's basically what warped rotors mean. I agree with you though, I would get new pads first, since you said you need them anyway, and see if it helps after you bed them in correctly.

Boostd4
09-07-2005, 09:28 PM
Apex or 442...have you guys upgraded to aftermarket rotors? I'm thinking of going with a 2 piece rotor when I change my pads. One of my friends is looking into this as well. Just wanted to see if you guys had any input/experience with something like the Performance Friction setup?

vtluu
09-07-2005, 09:42 PM
I'm picking up my 2-piece PF rotors from Gruppe-S tomorrow. Not sure if I'll put them on right away or wait until the next track day; probably the latter since the current rotors have plenty of meat left (after 8 track days and plenty of autocrosses). I have the R1Concept (same as Rotora) slotted rotors currently. Though I drove the snot out of the stock rotors and warping was never an issue with them either.

earlyapex
09-07-2005, 10:09 PM
Apex or 442...have you guys upgraded to aftermarket rotors? I'm thinking of going with a 2 piece rotor when I change my pads. One of my friends is looking into this as well. Just wanted to see if you guys had any input/experience with something like the Performance Friction setup?

Yea I put the performance friction 2 piece rotors on the car before it even saw the track. I saw what methods4 went through with 1 piece rotors and I didn't want any part of that.

I love them. 4 events so far and still rockin.

e8
09-07-2005, 11:32 PM
define chatter?

i was getting "chattering" at the end of my brake pad life, but i was positive it wasn't warping. warping is very appearant through the steering wheel and will shake even under light brake pressure at high speeds.

get new pads first, then think about resurfacing or possibly new rotors.

vtluu
09-08-2005, 12:56 AM
I got a bit of "warping" (pulsing felt under light braking) after Laguna Seca due to uneven pad material deposition but it wore off by itself after a few days. This was with the stock pads.

Check the pads (inside and out) first; if they're worn, replace them, bed them in properly, and see if that helps.

I have some stock rotors with some life left in them (I'd have to take a measure of the rotor thickness to say exactly how much) that I'd be willing to let go for cheap.

Evo442
09-08-2005, 05:03 AM
Apex or 442...have you guys upgraded to aftermarket rotors? I'm thinking of going with a 2 piece rotor when I change my pads. One of my friends is looking into this as well. Just wanted to see if you guys had any input/experience with something like the Performance Friction setup?

Currently I am testing some cryogenically treated slotted rotors which I have been very impressed with. No brake fade like with the stock rotors and are holding up very nicely vs stock. I have 5 track days on these rotors and they look better than the stock rotors after 2 days.

Honestly, I wanted and am planning to get 2 piece rotors, likely the PF rotors. Looks like its is going to take me longer than expected to wear down these cryogenically treated rotors, tho.

GokuSSJ4
09-08-2005, 12:04 PM
PF rotors are nice but at the moment only make a 2 piece rotors for the front (only). Another option that you have are Baer 2 piece rotors as well, they make an entire set (front and back) not cheap tho :?

earlyapex
09-08-2005, 12:23 PM
PF rotors are nice but at the moment only make a 2 piece rotors for the front (only). Another option that you have are Baer 2 piece rotors as well, they make an entire set (front and back) not cheap tho :?

You don't need the rears, unless you want them for bling.

Evo442
09-08-2005, 07:07 PM
Girodisk also makes matching front and rears

MitsuMan
09-08-2005, 07:42 PM
define chatter?

i was getting "chattering" at the end of my brake pad life, but i was positive it wasn't warping. warping is very appearant through the steering wheel and will shake even under light brake pressure at high speeds.

get new pads first, then think about resurfacing or possibly new rotors.
its called pulsation and it is the rotors, and you should resurface if your changing the pads or it'll still be there. hell you should always resurface the rotors to break in the new pads and to fight against noise. but I changed my first set without cutting the rotors and I was fine. I didn't have any pulsation though.

earlyapex
09-08-2005, 09:02 PM
hell you should always resurface the rotors to break in the new pads and to fight against noise.

I've never resurfaced a set of rotors in my life. But I also usually use slightly more aggressive pads than normal so...

MitsuMan
09-08-2005, 10:13 PM
oh, well I do it up to ten times a day so I might know about it a little

please believe me when it comes to cars I know my shit. I'm a seven year ASE certified journeyman tech and smog tech I'm just trying to educate on car stuff I don't know it all but when you install new pads you always want to cut the rotors to avoid getting a squeaky set of breaks the pads have to break in or create a wear pattern that matches pad surface to rotor surface other wise a smooth rotor will cause a new pad to chatter(vibrate at a high squeaking freaquency) this is a fact

earlyapex
09-09-2005, 12:12 AM
yes I know, I'm not doubting you. I was just saying I've never done it in my life and never had a problem....

e8
09-09-2005, 08:26 PM
its called pulsation and it is the rotors, and you should resurface if your changing the pads or it'll still be there. hell you should always resurface the rotors to break in the new pads and to fight against noise. but I changed my first set without cutting the rotors and I was fine. I didn't have any pulsation though.

So, then, explain to me my brake problem.

Under hard braking at speeds above 60mph, with my old pads towards the end of their life (~10%), I used to get a heavy chatter, not a pulsation, a chatter. This wasn't ABS. Also, the braking force was significantly decreased.

Under light to medium braking at all speeds, nothing. The brakes worked fine.

Replaced the pads without resurfacing the rotors and everything is fine. I don't doubt your knowledge, but I also do know what warped rotors feel like. Also, I don't know how I could've warped my rotors because...

1) I've only gone to the track twice with no qualms over the brakes afterwards.
2) I only lightly apply the e-brake.
3) I don't drive like a maniac on the street and rarely brake hard enough to make a difference.

Granted, there are an inifinite number of physical possibilities about the rotors that could cause warping.

MitsuMan
09-09-2005, 09:24 PM
sounds like they were just getting too hot because your pads were low and they weren't aborbing the heat enough, this probably change your coeffient of fricting and gave you a chatter. Did you also hear a dear growling noise? I have experienced this on cars with thin pad before I'd really have to drive it to Diagnose it though :?

EVO GRIM
09-10-2005, 03:59 PM
Had the same prob. with a warped front rotor. Turned them this morning and put new pads.... All better.

e8
09-10-2005, 05:45 PM
sounds like they were just getting too hot because your pads were low and they weren't aborbing the heat enough, this probably change your coeffient of fricting and gave you a chatter. Did you also hear a dear growling noise? I have experienced this on cars with thin pad before I'd really have to drive it to Diagnose it though :?

Yeah, I kinda got a growling noise.

What you just described could be the culprit.