Centric rotors - which?

[contemplative_shrimp]

Edit: Looked at wrong part # so no longer relevant

So I'm looking to buy some Centric front rotors. I'm seeing the high carbon 12561070 being cheaper ($28) than the regular blanks 12161110 ($33). I thought high carbon rotors were better/more expensive?

Which should I get for daily driving? I live in CA so no rust issue.

 

[WannabeST]

You are thinking of carbon rotors which are typically thousands of dollars per rotor. I doubt anyone even makes them for fiestas to be completely honest with you.

regular blank rotors are usually made up of steel.
High carbon rotors are primarily iron instead of steel. They just have carbon mixed in to be able to withstand the heat better.
There is also cast iron rotors which is basically the high carbon rotors without the carbon mixed in. or you can think of it as an iron blank rotor instead of a steel blank rotor

in my honest opinion rotors are rotors when it comes to stock setups, so just get the cheapest blank option. You most likely won't notice a difference at all, in different rotors. Brake pads will make for more of an actual difference. I personally run lifetime warranty rotors from Autozone because when they get worn down I can just get new ones for free.

if you really want the all out best option. Get a coated all steel rotor. Steel rotors are typically slightly lighter and can handle the heat better than iron. The only downside is just a couple bucks more and usually slightly louder than iron.

 

[contemplative_shrimp]

Thanks for the reply. In your opinion, would you take the high carbon rotors at the lower price vs the regular ones? Or pay extra and get the regular steel blanks?

 

[Dialcaliper]

You are thinking of carbon rotors which are typically thousands of dollars per rotor. I doubt anyone even makes them for fiestas to be completely honest with you.

regular blank rotors are usually made up of steel.
High carbon rotors are primarily iron instead of steel. They just have carbon mixed in to be able to withstand the heat better.
There is also cast iron rotors which is basically the high carbon rotors without the carbon mixed in. or you can think of it as an iron blank rotor instead of a steel blank rotor

in my honest opinion rotors are rotors when it comes to stock setups, so just get the cheapest blank option. You most likely won't notice a difference at all, in different rotors. Brake pads will make for more of an actual difference. I personally run lifetime warranty rotors from Autozone because when they get worn down I can just get new ones for free.

if you really want the all out best option. Get a coated all steel rotor. Steel rotors are typically slightly lighter and can handle the heat better than iron. The only downside is just a couple bucks more and usually slightly louder than iron.

Watch out - this isn’t correct and a common mistake

Standard blank rotors are grey cast iron (G250 or G3000 are the industry standard materials) and usually just fine for most street and even “trackday” cars. These cast irons have carbon content around 3.25%

“High Carbon” rotors are not stronger (if anything they have a lower tensile strength). There’s no industry material standard (exact alloy is proprietary for most companies) but typically have a higher carbon content around 3.65%

The additional carbon forms tiny nodules that increase thermal conductivity which makes them more resistant to thermal cracking and warping, and also absorb vibration, which makes them less likely to squeal. Which is why most OEMs have switched over to it.

Brake rotors despite general impressions are not typically under much mechanical stress - thermal stresses and heat dissipation and heat capacity (basically mass) are a much more important consideration.

Short answer, either will work. Centric 125 rotors usually have partial anti corrosion coating on hubs and vanes like Centric 121 “premium” rotors, while the 120 are usually bare. Any of them will be fine even for cars that see track use and track pads.

Steel rotors do exist. Solid steel rotors are lightweight brakes, usually only for drag cars because they’ll easily warp if you put much heat into them.

Also, some fancy aftermarket rotors are laminated steel to allow lighter rotors to be used. Despite the picture in the article below, even pretty drilled/slotted aftermarket rotors are not steel. This is usually reserved for only very high end two-piece rotors used in motorsport. (even most two piece use cast iron)

Here’s a good article if you’re interested

https://trade.mechanic.com.au/news/disc-rotor-materials-g3000-g250-high-carbon-what-the-flux

 

[contemplative_shrimp]

Whoops, I made a mistake. The high carbon rotors are for Rear. Sorry for the confusion!

 

[WannabeST]

Watch out - this isn’t correct and a common mistake

Standard blank rotors are grey cast iron (G250 or G3000 are the industry standard materials) and usually just fine for most street and even “trackday” cars. These cast irons have carbon content around 3.25%

“High Carbon” rotors are not stronger (if anything they have a lower tensile strength). There’s no industry material standard (exact alloy is proprietary for most companies) but typically have a higher carbon content around 3.65%

The additional carbon forms tiny nodules that increase thermal conductivity which makes them more resistant to thermal cracking and warping, and also absorb vibration, which makes them less likely to squeal. Which is why most OEMs have switched over to it.

Brake rotors despite general impressions are not typically under much mechanical stress - thermal stresses and heat dissipation and heat capacity (basically mass) are a much more important consideration.

Short answer, either will work. Centric 125 rotors usually have partial anti corrosion coating on hubs and vanes like Centric 121 “premium” rotors, while the 120 are usually bare. Any of them will be fine even for cars that see track use and track pads.

Steel rotors do exist. Solid steel rotors are lightweight brakes, usually only for drag cars because they’ll easily warp if you put much heat into them.

Also, some fancy aftermarket rotors are laminated steel to allow lighter rotors to be used. Despite the picture in the article below, even pretty drilled/slotted aftermarket rotors are not steel. This is usually reserved for only very high end two-piece rotors used in motorsport. (even most two piece use cast iron)

Here’s a good article if you’re interested

https://trade.mechanic.com.au/news/disc-rotor-materials-g3000-g250-high-carbon-what-the-flux

Thank you for the lesson. It appears I've been misled by the internet lol

 

[SteveS]

Centric says their 125 High Carbon rotors are iron alloyed with molybdenum and chromium. They claim they dissipate heat better, resist cracking, and reduce pad squeal with high friction European brake pads as well as increasing stopping power on repeated stops.

But apparently it's only available for the rear?

 

[Dialcaliper]

If you have a street car, Centric also offers GCX (Geomet) coated high carbon rotors. Non friction surfaces will stay bright for a very long time. Some reports that the coating will craze under heavy track use though.

Rockauto sells the rears. The fronts can be had other places online. The F and H denote full or half coating which is apparently to match the OE rotors (or OE pad type?)

Part numbers
320.61110F
320.61070H

Tire racks sells normal cryo treated centric rotors. Supposedly more resistant to warping under heavy use.