Looking for thoughts beyond my observations. The coated rotors I have seen have a uniform coating over the entire part that seems like just a thin zinc galvanizing dip. Doesn't seem like it will protect the non-wear areas from rust very long. Painted rotors (paint on the center hat and outer rim) seem to have a thicker and longer lasting coating. (Maybe epoxy paint?) Any other input?
Coated vs. painted rotors
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I can't speak about duration as the coated rotors I installed on the CX-5 are only a few months old but there is a discernible difference between the fronts which are coated and the rears which are not. I had surface rust start in about a week on the rear, the fronts are still as clean as they were out of the box.
I have a pair of eBay Brakemotive drilled & slotted rotors on the front of the xB in my sig. They were cheap, figured I would try cheap ones before going bigger, and they've been fine so far. They appear to be chrome plated, and the only corrosion in the year they've been on is at the wheel face/mounting area, guessing from dissimilar metals (alloy wheels).
I installed coated Zimmerman rotors almost a year ago. The coated part lasted a while but I just checked recently and it's pretty much all gone at this point and certain parts of the rotor are starting to rust, but it's not that bad yet, just light rust, still areas that haven't rusted yet. Rotors are basically iron so you've got to expect them to rust as their job is also to dissipate heat from the rotors.
The grey coating is supposed to be geo-met. Zimmerman and the german mfg's started it. The Asian rotors now have a similar process, but it is not the same.
The black paint is often e-coat, but many mfg's are moving away from this process due to the environmental issues.
Originally Posted by Wolf359
I installed coated Zimmerman rotors almost a year ago. The coated part lasted a while but I just checked recently and it's pretty much all gone at this point and certain parts of the rotor are starting to rust, but it's not that bad yet, just light rust, still areas that haven't rusted yet. Rotors are basically iron so you've got to expect them to rust as their job is also to dissipate heat from the rotors.
Did the geo-met coating last longer or shorter than the original MB rotors?
The black paint is often e-coat, but many mfg's are moving away from this process due to the environmental issues.
Originally Posted by Wolf359
I installed coated Zimmerman rotors almost a year ago. The coated part lasted a while but I just checked recently and it's pretty much all gone at this point and certain parts of the rotor are starting to rust, but it's not that bad yet, just light rust, still areas that haven't rusted yet. Rotors are basically iron so you've got to expect them to rust as their job is also to dissipate heat from the rotors.
Did the geo-met coating last longer or shorter than the original MB rotors?
Heat is what kills the painted coating, zinc will always last longer if using a qualty name. I installed a set of Zimmermans on the GL when I bought it, 3/18 and about 9500 miles ago, no rust at all on the hats, still shiny and grey.
Originally Posted by The Critic
The grey coating is supposed to be geo-met. Zimmerman and the german mfg's started it. The Asian rotors now have a similar process, but it is not the same.
The black paint is often e-coat, but many mfg's are moving away from this process due to the environmental issues.
Originally Posted by Wolf359
I installed coated Zimmerman rotors almost a year ago. The coated part lasted a while but I just checked recently and it's pretty much all gone at this point and certain parts of the rotor are starting to rust, but it's not that bad yet, just light rust, still areas that haven't rusted yet. Rotors are basically iron so you've got to expect them to rust as their job is also to dissipate heat from the rotors.
Did the geo-met coating last longer or shorter than the original MB rotors?
Bought the cars used so the rotors always had rust on them and the only aftermarket ones I've used are Zimmerman. MB can be lame sometimes, even their lug bolts aren't chrome and have rust on them. Got them from fcpeuro so they have a lifetime warranty on their parts so I'm not worried about the rotors.
The grey coating is supposed to be geo-met. Zimmerman and the german mfg's started it. The Asian rotors now have a similar process, but it is not the same.
The black paint is often e-coat, but many mfg's are moving away from this process due to the environmental issues.
Originally Posted by Wolf359
I installed coated Zimmerman rotors almost a year ago. The coated part lasted a while but I just checked recently and it's pretty much all gone at this point and certain parts of the rotor are starting to rust, but it's not that bad yet, just light rust, still areas that haven't rusted yet. Rotors are basically iron so you've got to expect them to rust as their job is also to dissipate heat from the rotors.
Did the geo-met coating last longer or shorter than the original MB rotors?
Bought the cars used so the rotors always had rust on them and the only aftermarket ones I've used are Zimmerman. MB can be lame sometimes, even their lug bolts aren't chrome and have rust on them. Got them from fcpeuro so they have a lifetime warranty on their parts so I'm not worried about the rotors.
I put Powerstop rotors on a VW New Beetle I used to have, because they were fairly cheap. They had a coating that almost looked like a chrome spray paint in color. Don't remember what they called it. Honestly after about 5 years of winter driving and daily use and about 85k I started to get some dots of surface rust on the hats and non wear surfaces. I was really surprised that the coating held up that long and just suffered from some discoloration. I think what I liked the most was that the area in the cooling fins was still coated and not rusting but simply discolored at this point. Never had an issue with them aside from being a bit noisy at times (Drilled and slotted).
Would def get the coated type rotors again for the performance they returned and the clean look. Might pass on the drilled and slotted part though.
Would def get the coated type rotors again for the performance they returned and the clean look. Might pass on the drilled and slotted part though.
Put some Raybestos coated rotors on our last Explorer. Ran it was two winters and they held up well in the Michigan salt belt. Unfortunately I (stupidly) traded it in on a new truck for the wife, so I don't have a long term report on the rotors.
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