DEVO

i'll say it again... the stock rotors for this car are tooooooo small.

Soze75

sauceman

I'm just a bit worried they'll be unable to reproduce the problem since it happens infrequently. I just wish I had a better idea of why it happens in the first place.

KJLite

after hanging wiith my buddy with a cl-s yesterday, i think our brakes are the same size as on the cl-s. i didn't bother looking up the specs, but eyeballing it, the rotors look about the same size. isn't the cl-s close to the weight of the tsx?

are there any cl-s owners complaining of brakes on their sites?

stop spitting back what the auto journalists keep saying.

sauceman

The only time I found my brakes were having a hard time was a few weeks ago when I had to make a 25min long high-speed dash (200-225kph) to a hospital in Montreal. The brakes started fading slightly before entering the bridges area. But even then, I did not experience warpage of any kind.

DEVO

I didn't know the journalist are saying this. i'm just looking at all the messages were people here have warped their rotors. I also have had the same thing happen in my gs-r. Again, the rotors for that car are too small. Braking in my gs-r is by far the worse thing about the car.

Now... the s2000, that is one of it's strong points... again i could give a rat's ass what a journalist thinks. I am stating what I have experience and these brakes are the best that I have ever tried on any car.

The civic hybrid, again, nice brakes for it's class.

captainjack

I'll back up Devo.

I've read plenty of posts here about warping. It happened to me too--mine were cut at my 10K oil change. They also replaced the pads for free.

My service rep told me warping was showing up on TSXs. I don't think he was "spitting back".

I'm following Killer's lead and considering the Brembo rotors.

majormojo

I'm in the "Honda rotors are weak" camp. This is my third Honda, the first two had weak rotors. Turning them fixes the problem but only temporarily as they are more susceptible to warping the thinner they get. In my experience, one good hard panic stop is enough to cause warping. It just shouldn't be that way. I have no idea why a company with such excellent attention to detail has let this problem persist for so long. It's never been an issue in any of the twenty or so other cars I've owned over the years.

That said, I bought the TSX hoping the issue would not re-occur, but prepared to live with it if it did. So far, so good.

DEVO

Well I was talking to a mechanic over the long weekend and he gave me some insight on warp rotor problems.

I always assumed that warp rotor come from heating the rotors under extreme braking and then having the rotors warp as they cool (going through a puddle of water for example). Well that can happen but that is a rare reason for the rotors to warp.

It all has to do with how the pads wear into the rotors and how well the rotors wear machined at the factory. A warp rotor turns out to be only warped under highly calibrated tools. Placing the rotor on a flat surface will still show the rotor to be flat. So turning the rotor usually solves the problem.

The only time he could think of a rotor warping is if rust has built up around the rotor except were the pads are when leaving the car alone for several days. If you go out and drive and have to come to a quick stop, the rusted part of the rotor will not cool as quickly as the clean section of the rotor. This difference in temperature can cause the rotor to warp. But he made it a point that this is rare and usually the problem is that there is a problem in the wear of the pads into the new rotors.

1killercls

Brake rotors are usually your basic gray crummy cast iron. Rotors for
production applications are almost always sand cast, and do have some
built in stresses from uneven cooling- the automakers really are
primarily focussed on cost, so the quality of these guys is pretty
marginal. They are usually overweight to compensate. They have sand
inclusions, bubbles, prosities, and they are usually cast in one piece
with the hub- which leads to some nasty stresses whrn the OD is
incandescent and the hub is cold. It also leads to cooked wheel
bearings, pronto. They almost always exibit quite a lot of core shift,
which leads not only to balance problems but also to premature warpage
(due to one working surface heating more quickly than the other). This
is worsened in brake designs where the pads are asymmetrical, like my
Mustang- the driven pad is smaller than the slave pad, so the heat
loads differ on the two faces of the rotor.

The aftermarket rotors available for racing applications (Coleman,
Brembo, and other vendors) are usually a better class of materials-
some of the ASTM high-temperature cast irons are the norm. The best of
these are usually vacuum degassed to eliminate porosities that can
lead to cracking. These are also designed to run on a separate hub
adapter (the hat), which eliminates one major source of stresses and
also cuts the heat transfer to the hub and wheel bearings.

Warpage is usually caused by differential heating, and it's not clear
to me that any sort of stress relief can be made to work for any long
period of time. I have warped and cracked more stock Detroit rotors on
my track car than I care to think about, and I can't think of any
mechanical or thermal stress relief technique that might help them. I
routinely used to run the rotors well up into the bright orange
incandescent range- any rotor, no matter the quality of the original
casting, will begin to behave pretty erratically at these temps!

The best way to keep rotors alive is to keep them cool. _Massive_
quantities of air ducted right into the rotor eye, and kept there with
a blanking plate that more or less fills the eye, is the ideal. The
vanes will pump the air through the rotor and help with the airflow.
Wheels that help exhaust the hot air outboard help as well- my best
results on the stock rotors have been with the old Kelsey-Hayes
3-blade "blower" wheels- they were ugly as sin, but they moved a lot
of air out of the wheel wells. Keeping the rotors cool will also pay
amazing benefits in pad life. My finding has been that pad wear, even
with carbon race pads, goes up exponentially once rotor temps reach
about 800degF.

The next best way to keep rotors alive is to heat-cycle them very
gently. Take a lap to heat them up to working temps, and use the
cooloff lap to cool them gently. If you're on the street, and intend
on some heavy driving, the same rule applies- heat them gradually. An
absolutely guaranteed rotor killer is to do a max-effort high speed
threshold braking maneuver on cold rotors. Cast iron's thermal
conductivity is really pretty poor- so the surface will go up to
_insane_ temps, with the vanes between the faces still dead cold. The
thermal stresses are immense, and the stock low-quality casting won't
take it. Surface heat checking is the best you can hope for! I refer
to this kind of stop as "the rotor giving its life to save yours".

The last thing to help keep rotors alive is to work on your braking
technique. As you roll onto the brakes entering a corner, come on them
progressively and smoothly, and _slowly_ increase the pressure until
you get to the threshold. Luckily, this is also the best way to keep
the car balanced entering a corner, so it's a useful exercise in that
respect as well. If your braking style is one of planting th car's
nose _all at once_ when you get to the braking zone, you might want to
try working on braking a little easier, a little earlier at the start.
You'll find that you can then brake harder later in the corner, and
the wight will transfer more gently.

It's a subtle thing, but what you're trying to do is to spread the
heat load in the brakes out over a little bit longer time- and more
improtantly, reduce its peak value. For the massive, 11/10s, fully
committed, hairy outbraking move, then do what you've gotta. But if
you aren't under pressure to pass or be passed, work on being gentle
and progressive with the pedal.

Drilled and milled rotors are great for racing, if done right. I'm
running nothing but carbon pads these days, on a very heavy car for
road racing, so playing with the rotors is not good for me. Drilling
can aid in cooling, and aids in fade control by providing a place for
the high temperature gases to escape to, but can lead to warpage and
cracking much earlier if the car is seriously underbraked. The holes
need to be drilled and chamfered in such a way as to avoid creating
new stress raisers, and I have never figured out how to do that very
well. Milling consists of cutting a shallow groove in the rotor face,
also to provide a gas escape- I like this better, since it creates
less in the way of a stress raiser if a radiused groove is used. These
days, I just slot the _pads_ for fade control, and leave the rotor
alone. IMHO, for an underbraked car on stock rotors, drilling or
milling is a waste-you'll be throwing them away very soon, and the
removal of metal is almost certain to make that sooner.

Before I did good brake ducts, I used to go through a set of carbon
pads a day and a set of rotors in a weekend on my nice overweight
Mustang GT track car. With ducting, I get 4 days out of pads, and
about 4 out of rotors (using the stock rotors). I've since gone to
custom Coleman directionally vented rotors on custom hats, and I don't
have enough data yet to predict long term life, but it looks like I
might be able to keep pads on the car about 4 days, and the rotors
might last a season. Which is the next best thing to _immortal_, to
me. I've got a pile of rotors that are cracked so badly you can see
light through 'em in the garage...

If you are going to run a stock 1-piece rotor hard, you _must_ use a
good high temp synthetic grease (Mobil One or Redline) on the wheel
bearings, and keep after them. Any stock grease will melt out and
blow by your grease retainer, leaving you with dry bearings. Been
there, done that, back when I first started playing with the car on
the track.

http://yarchive.net/car/brake_rotors.html

chrisalberts

Thing is, none of that should be necessary on a vehicle driven on the road in a normal-sporty fashion. If the brakes are warping in normal use then one of two things is happening:

1. manufacturing defects in these particular rotors

2. design defect in the braking system (in which case most TSX owners would be having problems.

End of story.

As for the old "clutches cost more than brakes" argument, the flaw in the logic is the incorrect assumption that shifting gear wears out the clutch in a measurable fashion. 99.9% of clutch wear is from setting off from a dead stop, shifting while moving is not even a factor in clutch lifetimes. (This is assuming that the driver isn't doing dumb stuff like holding the car on the clutch at lights and on hills.)

I'm not saying that people should routinely slow down on the gears rather than the brakes, but what I am saying is that they're not shortening the life of their clutch by doing so. Surely even an engineer can understand that.

C.

1killercls

This MECHANICAL ENGINEER Disagrees...sorry.

KC 2004 TSX

What do you disagee with? Are you an automotive engineer?

1killercls

Nevermind...It just doesn't matter. :shakehd:

KC 2004 TSX

I was serious. Do you disagree with the rotors the clutch or both.

chrisalberts

I'd like to hear this too. I just reread the entire thread and nowhere does the nameless mechanical engineer actually explain why he feels it noticeably wears the clutch when you're shifting. Just saying something louder over and over again doesn't make for a cogent argument.

All that stuff about heat management being the key to rotor longevity is all true, but doesn't really address the point of why a stock car being used in a normal fashion on public roads is warping its rotors.

So c'mon 1killercls, if you've really got a point on this, please share it. I'm not an expert and not an engineer of any kind, but I do understand how the major systems of an automobile work and I'm willing to be proved wrong but you can't just keep relying on your status as a mechanical engineer, SCCA racer etc. and expect us to take your word on everything.

C. <-- car came stock w. 4 piston calipers and drilled rotors and ducting - no braking issues here.

KJLite

I can follow your clutch logic, but engine braking will put more wear on engine itself. probably not too significant, but if you routinely engine brake, rather than coasting, the engine is spinning at 3-4k rpm, rather than at idle speeds. wouldn't this equal 3-4 x the amount of wear on the engine.

in other words run an engine at idle for a week straight, then run it at 3k rpm for a week straight. you should see 3 times more engine wear. does this make sense to you? its kind of a hard point to get across.

1killercls

Clutching Issues. That is what I disagree with.

Engine wear, clutch and trans wear throwout bearing wear as opposed to.... pad, rotor wear, and bearing wear.

I pick the LATTER.

If you had to pick what items to repair, and the cost involved to rebuild, repair or whatever it would take to make it 100%...which would you choose???

It kind of falls under LOGIC and Common Sense. Very little of my opinion has to do with the fact that I am an engineer, it is an opinion that has been formed over experiance and learning from individuals more knowledgable than myself sharing information.

In the future I will remember not to be so fast to try and offer help.

KC 2004 TSX

Thanks. I wasn't looking for a fight, just clarification.:o

RogerPodacter

Thanks for all of the replies, but to get back on topic for a second.

Everyone who is arguing coasting is better than engine braking - thats exactly what i did for the first 10K miles, and guess what, my rotors warped. i totally agree that given the two choices, wear and tear on brake pads is a much more logical option than wearing an expensive engine, clutch and drive train.

so for the last 8K miles i have been downshifting. the few instances where i had to brake hard, without time to downshift, is where i beleive my rotors began to warp again. i really think this is a defect, or is caused by the rotors being thinner from the first cut.

i also beleive that if i had used downshifting for the first 10K miles, there would have been no first warping issue in the first place, and hence no need for rotor cutting - which led to the second warping of thinner rotors.

sauceman

Roger, hopefully I will have enough time soon to post an article I read about brake rotors that may come to use and help you and others on the brake issues here. Watch out for it, it's coming.

rb1

Yup. This is when almost all rotor warp occurs -- hard braking heats up the rotors very quickly and causes warping if the heating is uneven (due to improper pad seating, perhaps by not breaking in the brakes carefully or uneven rotor surface), or if there is insufficient rotor mass to absorb the heat.

All the downshifting and engine braking in the world won't do much protect your rotors from a hard stop using the brakes. It's especially bad when you have to stop from highway speeds -- like when everyone on the interstate slams on their brakes at near 80 mph (a routine event, locally).