Topic: Rusty Rotors on S2000

[Bubba]

Spotted this rotor on a new S2000 at Corwin Honda in Fargo, ND.  How quickly can rotors rust like this and can you simply drive away with them and have no issues?

[johngenx]

Very light surface corrosion from sitting.  A couple stops and its gone.

[Mitlov]

My old Legacy had rusty rotors when it was one year old, though not nearly this bad.  Curiously, I drove it nearly everyday.

[dr_spock]

Very quickly.  My rotors rust overnight after washing the car.  The surface rust comes off quickly after a couple of brake applications.

[ilovecables]

Replace 'em with some nice cross drilled plated rotors - they don't get any surface rust, and they perform better. 

[xviper]

Replace 'em with some nice cross drilled plated rotors - they don't get any surface rust, and they perform better. 

This is a proven fallacy, at least for an S2000.  The OEM brake components on an S2000 do such a great job that few, if any, aftermarket rotors will perform any better.  In fact, cross drilled rotors are ill advised for an S2000 that is tracked.  They have a tendency to crack between the drilled holes in high heat situations.  Cross drilled rotors look pretty but do little for better braking performance on this car.  If you need better water shedding and off gassing, slotted rotors are recommended.  The rust situation is pretty common on S2000s.  As already said, they'll rust right after a car wash but will scrub off with the first brake application.  Not a real big deal, but to side step this, you can get aftermarket rotors that are cadmium plated.  They don't even have to be slotted.
The rust depicted in that picture is from being left unused for extended periods of time.  One that is driven regularly won't ever look that bad.

Note:  After a car wash, leave it in gear, but don't apply the ebrake.  This will minimize the loud CRACK you'll get if you park it for a while and then take it out for a drive.  The noise is the pads breaking free of the rotors due to the rust build up.

[barrie1]

Its a very common thing for rotors to rust quite badly even over night on occasion as its the nature of the metal and the surface of it. Yes a few good stops generally does clean it mostly off and they are as good as new. 

[wing]

Those rims are different....

[xviper]

Those rims are different....

Those are the '08 OEM rims on the S2000.

[Cord]

I wonder why car makers don't employ the same technology used on motorcycle rotors to keep them looking good, especially on those models where the rotors are very visible.

[dr_spock]

Looks like there are couple of deep grooves on that rusty rotor.   Is that a good or bad thing? 

[xviper]

I wonder why car makers don't employ the same technology used on motorcycle rotors to keep them looking good, especially on those models where the rotors are very visible.

This is a very good point.  I think there are many factors that contribute to why this is.  Typically, a motorcycle's brakes have much less weight to deal with when bringing the vehicle to a stop.  We see fairly large diameter rotors, with multi-piston calipers on bikes.  One can say that motorcycles are "over-braked" as compared to cars.  Thus, they can be made thinner and of materials that don't have to tolerate the stresses of a car application.  Those same materials can be of rust resistant characteristics.  Having been a motorcycle instructor for many years, I can tell you that the average motorcycle will out stop the average car, when driven by the same sort of corresponding driver experience.  There is no need to build such "heavy duty" brakes in a bike and it's this HD nature that lends to materials that are prone to rust.  Motorbike brakes are fairly simple, yet can be exotic in what goes into them.
Car rotors can also be plated so they resist rust, but as we can see from aftermarket vendors, they tend to be much more expensive and they don't necessarily work any better (sometimes worse) than OEM parts.  The S2000 has some of the best brakes today.  They were designed for a car that was meant to be auto-crossed, tracked and raced.  Plating them to resist rust has actually been shown to diminish their capabilities.  Honda elected to go with performance, rather than aesthetics in this area.  I'm sure that other manufacturers also consider the "bottom line" when selecting the parts to build a car.

[xviper]

Looks like there are couple of deep grooves on that rusty rotor.   Is that a good or bad thing? 

Can't really tell if those are deep grooves or just lines where the rust didn't form (for whatever reason).  If they are indeed grooves, that would mean that something abnormally hard was either embedded in the pad or is part of the pad, caused those grooves during what little stopping that car was subjected to.  Grooves that early in the car's life is not good, however, I'm tending to think this is not the case here.

[carthatgoesboom]

The rotors on my taurus were rusted after a big thunderstorm.  After I drove around it was gone.

[Rupert]

The rust in the picture is not significant...it is pretty usual for discs. If you enlarge the photo though the grooves seem to be notable. Weather this is a sign of a problem or might be bothersome is not known.