93civiccpe

Hello,
I purchased some brembo cross drilled & slotted rotors and some performance brakepads for my 93 civic coupe. I have no major mods on the car, but it is lowered with coilovers and gas shocks, and it has a strut tower bar, rear strut bar, and front and rear tie bars underneath. The handling is excellent, and I recently upgraded to rear disc brakes that were pulled off of an integra. When I put the new rotors and brakepads on, the car stops fast and hard, but at higher speeds if i even lightly push down my brakes the car shakes a little. Usually I notice it on highway driving, but sometimes I notice it when driving 45-55 mph but not as bad. My first assumption was to assume warped rotors, but they are brand new and we checked them when we got them. I was wondering if anyone else has had similar shaking and if it is due to the slots/drilled holes and air flowing through them. If anyone has information on this then please let me know. Thanks! -shaun

leolo007

I dont know much about this but since no one has answered I'll give my opinion. First of all it sounds like warped to me too. but I do know that the direction of the slots makes a difference too. If the lots move from center out against the rotation of the wheel, Ive heard that causes a lot of friction and braking is not as smooth. Im not sure if your experiencing what that or something else.

gear

you have warped rotors, id bet good money on it. air flow would not cause any of sort of shaking.. the only other thing that could cause the shaking would be a wheel bearing, but when those go bad, they tend to roar...

ToyotaTechGeek

depends on the brake pads you're running. slotted rotors are made to help keep the pads from glazing. they act to 'cut' the glaze right off. however, if you put a semi-metallic or any of the carbon/kevlar/ceramic pads on them, they thend to chatter.
cross drilled usually don't have the troubles, but i'll bet it's due to the slots.

94 Teggy

warped

Woodrow

Have you checked to make sure the runout is correct? That will cause a shaking feeling if it is incorrect. If you put new rotors on the hub and the hub is dirty it will throw off runout specs. Sometimes overtighting a lugnut can throw off runout as well. Just another avenue to look before you assume they are warped.

Get a dial micrometer and use that to measure the thickness around the rotor.

93civiccpe

Thank you everyone for the suggestions. The only reason I am thinking they shouldn't be warped is that I got them brand new from factory and they looked fine when we put them on.. no high spots or anything. The shaking is really only noticed when I lightly push the brakes down going around 75 usually. I don't feel any shaking when driving around in the city going 50mph or lower. I am using the performance ceramic brake pads so maybe that has something to do with my problem. Before I put the new rotors and brakepads (and rear disc brake conversion) on I never had this vibration, but the car didn't brake very well. Now that I have these on the car brakes way better but I noticed this shaking up at higher speeds. And the high speed vibration was there from day one.. so I just don't know. My mechanic who did the rear disc conversion for me said the same thing, he didn't think it would be warped rotors since they are brand new, and he though it may have something to do with the cross drilled & slotted rotors or maybe those heat reducing ceramic brake pads. I will check the things you guys mentioned, and if nothing else I may have to meet up with some of you one of these nights and just let you drive it and see what you think. Thanks again for all the suggestions!

>by the way, the slots go inside out with the direction not against it, and I will check the runout this weekend. BTW.. where do you guys meet up during the weekends.. I live in NN and I think I know one of the places because I saw a bunch there one night when I was with my girl, but someone pm me or I'll just go check that spot out this weekend if I get some time.

ToyotaTechGeek

i had a cousin who eventually removed his slotted rotors 'cause he was tired of the 'pulsing' and 'shaking'. this speaks volumes of mods i talk about being just too much for daily drivability. yes, sometimes performance is increased, but streetability is lost.

93civiccpe

Well, I wouldn't go that far... it isn't very noticable unless you are at a high rate of speed... driving through the city I never feel it.. only when I have to suddenly brake on the highway. It's not that the pulsing annoys me, I just wanted to make sure there were no safety issues. The rotors don't bother me.. i'm actually grateful to have them since they slow the car down so much better... now the fact that the car is lowered with tires too wide for the car... that is a mod that affects the daily drivability of the car.. ahahha.

StpH8n

I wouldnt think that the rotors came warped, I think (although possible) it is highly unlikely. I would check a few other simpler things. Like tire balance and alignment. Also, like was mentioned by someone else, over torquing the lugs can cause your problem.

I myself have brembo slotted and cross drilled rotors (93 dx coupe) and have never had any problems. Much props to PIP for the install too!!!