CO671

iTrader: (1)

(Ej6 Sedan DX)
My passenger side rotor's being eaten up... I didn't really look at it in a few days (when I started to hear the metal-to-metal sound) so I ordered some brake pads (still waiting for them to come in) and was planning on getting the rotor resurfaced too. Would it be too late now, and if so would I buy 2 rotors or just the replacement for the bad one?

jbpnoman

You should replace both rotors together. Take it to a shop, and have them measure it to see if it'll be within spec after turning. If they're both still within spec, just use them. If they aren't, get new ones.

EsotericImage

iTrader: (8)

+1

ribal_gh

Better to get new rotors, resurfacing the current rotors will effect your brake preformance, beacuase the rotor will be hot faster since they will become thinner.
Change rotors and pads at the same time man.

jbpnoman

Don't waste money on new rotors every time you replace your pads. There are zero people on this forum who will notice the difference between rotors with 2/100" shaved off.

ribal_gh

I did nto say to change the rotors every time you change the pads!
The pics shows clearly that rotors are in bad condition.

CO671

iTrader: (1)

I don't think he meant he changes rotors each time the pads are to be changed; but meant to say change my rotors when I changed my pads. That was the alternate plan anyways; i don't want to use new brake pads on that bad rotor... Looks like i'll just pick up some rotors too.

jbpnoman

If no one here worried about their pockets, we wouldn't be driving 10+ year old econoboxes. It takes next to no time to have a shop check the rotors to see if they're still within spec. If they're within spec, and can be turned, there is absolutely zero reason to replace them. I can't see exactly how thick those rotors are from a picture. I'm sorry. I'm good, but I'm not that good.

OP, take them to a machine shop, tell them what car they came off of, and ask them if they're within spec. If they are, a turn will cost you next to nothing. If they aren't, get some new ones. It really is that simple. No need for guess work, and no need to waste money. I've never charged someone to toss my caliper on their rotor and look up specs, and I've never heard of a shop charging for it.

DSMAddicted

If you wind up getting new rotors, I recommend going with new ones with warranty from AdvanceAuto or AutoZone.
You can get a new set every couple of years, no questions asked.

chiprez

Doesnt look to have much metal/metal grinding on it. Have it measured out or do it yourself, if within spec; re-surface.

Im actually replacing the rotors, calipers/drums and lines on my car only to get a fresh set up for auto-x i plan on doing.

gzes

I've had my rotors resurfaced on mulpile cars and it won't do anything noticably different..... I would just resurface them a lot cheaper then rigors. For me it was like $20 per car

speedjunkie_g35

Oriellys can turn your rotors and a lot of part stores. It is usually about 10 bucks a rotor

ej1ryder

If shes just your daily grocery getter/commuter, have them mic'd and resurfaced (if in spec). If you drive hard, brake hard etc... Then new ones are in order, removing material will make them heat up faster, and by the same token they are more prone to warp. If you enjoy spirited driving, it wouldnt be bad choice to look into a set of slotted replacements (powerslot,ebc,brembo) and some nice pads to go with em (i like ebc green stuff). Wont cost much more than oem replacements and your braking will be noticeably better and they will last longer.

toconn

Turning them is dirt cheap. If it's just a grocery getter, you could get brand new blanks from your local autoparts store for pretty cheap too though. I dont really see a differnece either way.

jbpnoman

Slotted rotors are ****. Don't waste your time or money on them. Anyone who tells you any different is not an engineer, and doesn't understand how brakes work. Drilled rotors are even worse.

ej1ryder

i disagree. your pad and rotor never actually come into contact with eachother under hard braking, because a thin layer of gas developes from the increased friction and heat being generated from the pads compound coming into contact with the rotors metal. the "more surface area being grabbed the better" argument only pertains to braking in light and moderate conditions where friction/heat doesnt build to the point of emitting gasses, the gasses will actually prevent complete contact of the two materials. this is where the slots come in, acting the same way as grooves in tire tread for displacing water/dust/debris, the slots provide a place for the gasses to go under high speed/high temp braking. i could argue the same and say "tread is pointless on tires from an engineering standpoint, because the less interrupted the contact patch is, the better". Obviously that would be false, unless your on a smooth race track in dry conditions. in order to effectively apply any kind of engineering, you have to keep in mind your intended application. Obviously brembo and similar companies know what they are doing. do you need slotted rotors on a grocery getter? NO. do you need slotted rotors on a car the sees a lot of hard braking? NO, but they sure would help.

I completely understand how brakes work, and i see where you are coming from. But there is always unforeseen obstacles, and conditions, that force the engineer to recalculate his formula for the intended application. thats why rudimentary inventions improve over time.

jbpnoman

Disagree all you want, then look at the rotors on some of the fastest cars in the world. 99% of them are blanks. I don't think anyone can argue the fact that F1 cars see some of the hardest braking of anything with 4 wheels and a gas pedal.




You could also talk to my step brother. He works at the VW/Porsche/Audi dealership. He's one of two techs who are "factory authorized" to touch the Audi R8. At a Porsche seminar, an engineer stood up and explained why they put slotted and/or drilled rotors on their cars. "Because people like the way they look."

Slotted and drilled rotors are a complete waste of money. If you really feel like wasting money on brakes none of us will ever see the full potential of, look into the Mugen Active Gate system. That's REAL brake cooling.

EBC pads, Brembo blanks. That's all you need to know for a grassroots track car.

ej1ryder

those rotors are made from an entirely different material than anything you would see on the road, or even many race tracks. cmon now we cant go comparing street brake setups to friggin F1 cars, that just reachin too far man. you would have to present a schematic from one of those engineers to convince me of this. many race cars around the world, in many different classes employ slotted rotors, and they are NOT buying them for looks. thats just a german engineers inside joke. wen you start getting into applications where you have multi piece/multi compound rotors the reason behind displacement slotting becomes pointless. i didnt say "F1 cars are teh fastest they need slotted brakes".

ej1ryder

JGTC time attack car brake setup. some of the fastest cars in the world that even resemble the shape of their road going counter parts.



i rest my case. Although, im sure they were employed for their looks

ej1ryder

found something i agree with. dropping subject.

jbpnoman

Ok, maybe F1 cars with Carbon discs are a bad example. You're right, different compounds, completely different topic. I will, however, leave this here.

SLOT + DRILLED rotors, bad idea?

People much more knowledgeable about brakes than either of us have already spoken up in that thread. Specifically, Liberteriat and 94eg!. They both know their **** when it comes to brakes. They both agree with me that blanks are the best brake replacement option for our cars, street or track.

ej1ryder

and ill settle with this, its obvious u and i know more than the average joe. and i will agree that others in the world know brakes better than us. but the subject is too application/condition sensitive for either of us to be correct, thus we are both correct, just in different areas and examples concerning engineering standpoints of braking mechanics, and their intended use.

lol i doubt 90% of people in this thread even comprehend the **** we talked about. good **** man from me, been a while since i got into a logical debate on the internet that didnt get nasty/ignorant/locked.

jbpnoman

I mean, if you want, I can start throwing around the racial slurs

I only talk down to people who are below me. You aren't. Most of the regulars on HT are pretty damn smart - that's why I've stuck around for a while.

ej1ryder

LOL. Ive heard em all . Yeah there is an impressive wealth of knowledge within the regulars of this forum, i think im here to stay, .

CO671

iTrader: (1)

Average Joe here; thanks for the argument, learned quite a bit on rotors there and surprised at how it ended.