[Bob Lincoln]

ALL brake rotors are made in China. All of them.

However, some are cast there and the final machining is done in the US. Centric claims to be the only brand that does the value-added here. I'm running them in my car now, and they work great, are quiet, but do put out the usual amount of dust on the rims, using Raybestos pads.

 

[B10alia]

I don't think that machining in the US is going to help anything in terms of wear. Poor-quality metal is poor-quality metal. Not to say that the Chinese aren't capable of making good steel or cast iron, they certainly are, but good metal is more expensive to make. The assumption nowadays is pretty much that rotors get junked with pads, because they're so cheap.

 

[68RT]

One thing that helps is simply mass. Check the weight of the rotor you are thinking about buying. The heavier, the better.

 

[Bob Lincoln]

I don't think that machining in the US is going to help anything in terms of wear. Poor-quality metal is poor-quality metal. Not to say that the Chinese aren't capable of making good steel or cast iron, they certainly are, but good metal is more expensive to make. The assumption nowadays is pretty much that rotors get junked with pads, because they're so cheap.

There is a lot of helpful background info at the Centric site. It's heat-treating that is often inadequate in China, not just machining. I probably didn't go into enough detail. It's not specifically 'poor-quality metal' to start. I've looked into this in the past.

Rotors a decade or two ago had heat treatment extending about .050 inches or so into the depth of the metal. This ensured a hard surface for wear longevity, and you could get 1-2 turns out of the rotor before discarding. They also have a stamping in them for the minimum rotor width, something like 229 mm.

What has happened in recent years is that many overseas sources only heat-treat them to a depth of about .010 inches. This means that they can wear out quickly, and once the hard surface is gone, the soft metal below is cut into easily. That's one reason why some rotors only last 10K -20K miles. The other failure that can happen is that this thin surface sometimes chips away (I have experienced this), and you'll get flaking rotors, which cause vibration and poor braking power, and can damage the pads.

In addition, whether deliberately or a misinterpretation, the "Minimum 229 mm" specification, which was meant that this is the thickness at which it is discarded, has been replaced by product which comes out of the box new at 229 mm. Therefore, as soon as you begin using it, it's below the minimum thickness, can't heat-sink as well, and will wear out faster and fade more for that reason.

Combine the two, and you have the $11 junk that we often find in the stores today.

If Centric or others can get a blank that's thicker than 229 mm, they can heat-treat it and machine it to perform as originally intended.

 

[neon98rt]

so the future is
can i fill your tank , check your oil and change your rotors at every tank of gas?

 

[Bob Lincoln]

:rimshot:

10 months and 11,000 miles on my Centric rotors, so far so good.

 

[B10alia]

What about those REALLY expensive slotted rotors you see on high-performance cars? Are those also made in the good 'ol PRC to the same standards?

 

[neon98rt]

i just bought some centric ones . JC whitney has them on ebay for 4 dollars less each than their site.

 

[neon98rt]

i got them and they look nice.

The old ones didnt look that bad. Maybe two credit card thickness worn on both sides on the inside. Must have been enough to make a noise .

 

[B10alia]

I hope you meant two credit cards overall, not per side-- I just stacked up four and that's a very substantial amount of wear.
I think the noise issue could have been from not bedding the pads correctly. There's a specific cycle of heavy braking you're supposed to go through to make sure that the rotors get evenly coated with fresh pad material. Otherwise, you can get squealing.
I think the main concerns with the rotor thickness are to keep enough material on the rotor to handle thermal loads (more mass=more thermal capacity, as someone noted above) and to provide a safety margin of wear. Usually when rotors go "bad", they warp, which gives you vibration. This is from overheating a rotor that is already at its lower limit of wear. Squealing usually comes from the pads or junk on the rotors, not from rotors which are too thin.

 

[neon98rt]

i think the pad was hitting the edge of the rotor that was not worn down by the pads. The noise was gone when i put new rotors in.

2 credit card per side

 

[Bob Lincoln]

2 credit card per side

I just measured my credit cards with a vernier caliper. I got 0.031 inches each. So if you were worn down 0.062 inches, those rotors were shot, the way they make them today. You were past the hardened surface and cutting into the softer iron.

 

[neon98rt]

yeah i havent seen that much wear in such a short time ever. I am sure i got them at autozone.

 

[B10alia]

.062 per SIDE, Bob. Almost an eighth of an inch overall. I wouldn't buy that brand again.

 

[Bob Lincoln]

.062 per SIDE, Bob. Almost an eighth of an inch overall. I wouldn't buy that brand again.

Yes. The official wearout is determined by measuring the thickness of the rotor vs what is stamped into it as a minimum. However, in the old days, there was .050" or more of hardened surface on each side. So even old, quality rotors would be worn at this stage. Typically back then, you could turn a rotor twice, removing .030 inches each time. Do that once today, and you have already removed the softer metal.

 

[B10alia]

But then again, with a deeper hardening, it would have taken longer to get there.
I remember hearing a while back that the Mopar rotors were junky as well. IIRC we had warped rotors on our Caravan in less than 30k that had to be scrapped. Not sure that that's as much a hardening or machining issue as it is poor manufacturing quality-- the van is a 2005, so this was Daimler at its finest (read: excessive cost-cutting). I remember a thread on here when I first joined about similarly poor rotor life on a Ram of similar vintage.
This very gray cloud does have (somewhat) of a silver lining, though. Rotors have now come down to the point where they're essentially expendable. I think my Spirit still has original rotors, but when those wear out, I'll probably go to changing the rotors and pads all at once. As long as the rotors are reasonable quality, I wouldn't be too concerned. Stay away from the store brands, and look for a reasonable name-brand that you'll be willing to replace in a few years with the brake pads.

 

[Musikmann]

I go to a NAPA sponsored shop and they replaced front pads and rotors about 5000 miles ago. We went with their Ultra Premium line and so far so good. I tried to get Mopar and couldn't but these seem to be good quality..

 

[A-Body]

But then again, with a deeper hardening, it would have taken longer to get there.
I remember hearing a while back that the Mopar rotors were junky as well. IIRC we had warped rotors on our Caravan in less than 30k that had to be scrapped. Not sure that that's as much a hardening or machining issue as it is poor manufacturing quality-- the van is a 2005, so this was Daimler at its finest (read: excessive cost-cutting). I remember a thread on here when I first joined about similarly poor rotor life on a Ram of similar vintage.
This very gray cloud does have (somewhat) of a silver lining, though. Rotors have now come down to the point where they're essentially expendable. I think my Spirit still has original rotors, but when those wear out, I'll probably go to changing the rotors and pads all at once. As long as the rotors are reasonable quality, I wouldn't be too concerned. Stay away from the store brands, and look for a reasonable name-brand that you'll be willing to replace in a few years with the brake pads.

Just got rid of my 72', B300 Dodge van (bought new) that had the same rotors with over 250,000 miles on it. I do recall if needed, they were over $200.00 each. So I always made sure I changed the pads before waring out.