Why pay to machine rotors if you can get new rotors for 11 bucks?

[vancouverbc]

rotors are so darn cheap!

[SmithSR]

True.On the scientific level I'm sure there are differences in quality and finish of the final product, but for a regular car, cast iron is cast iron.

[Q45tech]

Cast iron IS NOT cast iron as there are hundreds of suitable formulations in the amount of additive metals plus carbon/silicon added.......then the temperature cycling.

http://www.meehanite.com/flake_graphite ... al-ihm.pdf

Brake rotor iron requires specific graphite morphology, carbon content and strength to work well!!!!!!!!!!!!!

http://www.ms.ornl.gov/htmlhome/rsuc/rotor.html

"Depending on the specific material machined, chemical reactions may occur between tools and workpieces. For PCBN tooling, this is dictated by the chemical affinity between the CBN matrix combination and the workpiece material. The physical composition of cast metals produced by different foundries can vary widely, even when the parts conform to identical specifications. For example, machinability of gray cast iron varies widely, depending on the source.

This was demonstrated by a study in which the same cast-iron part was produced by nine different foundries. To discern differences in machinability, the test castings were machined with both a high-percentage, PCBN tool and a conventional silicon nitride (SiN) tool. The results in Figure 6 compare tool wear when machining castings made by various foundries. Tool wear is based on the volume of material removed per unit of flank wear (cm³/0.025 mm). Although all tested workpieces were machined to identical specifications, tool performance varied significantly. The results also indicate a significant advantage for PCBN tooling compared to conventional SiN tooling. The degree and type of PCBN tool wear is illustrated in Figure 7. As shown (left), the cutting edge has large amounts of irregular flank wear. This indicates a chemical reaction between the tool and the iron workpiece. Conversely, the smaller, more regularly shaped wear pattern (right) illustrates normal abrasive wear.

In connection with this study, intensive chemical and metallurgical analyses were also conducted to identify variables in these castings that might explain the substantial variation in tool performance. Although these analyses identified no specific causes for this variation, one factor was studied that might be relevant. An “aging” phenomenon for cast iron occurs in some industrial machining applications. This aging occurs when cast iron is stored for various time periods prior to machining. "

http://www.mmsonline.com/articles/010102.html

[SmithSR]

If a kid's road going commuter would noticeably change from one shelf brand to the next, then you'd have me.

Sadly, the radio and cell phone are paid more attention than the chemicals that were introduced to the brake rotor composition.

Day to day dealings with people who need a general explanation has taught me that.

People drive around with french fries on their floorboard. Crawl then walk.

[vancouverbc]

Bought my rear rotors today for 20 bucks each canadian from Lordco in Surrey. They have to meet government safety standards so I am not worried. Im just a commuter.

[chmercer]

smithsr, q45tech, if i had a set of project mu rotors, and a set of autozone rotors, what difference would i notice between the pairs? ive never heard of hairline fractures on solid rotors but im sure it could happen. increased wear, increased chance of warping, possibly unbalanced, lower heat dissipation threshhold? things of that nature? ive heard of people roadracing on autozone pads and rotors and throwing them away at the end of a session, so i was wondering if there are any dramatic performance differences, as opposed to things noticed by joe commuter.

[skydragoness]

All I know is that $11 is suspiciously cheap... ..

[Exar-Kun]

Fricition characterisitcs, the size of operating temperature range, heat dissipation, etc are all affected by the quality of design, manufacture and materials used on any brake product.

-Chet

[sean8564]

I agrre you can buy new brembo Rotors from NOPI for like 25 bucks and it's like 15 to have them turned. Just buy new

[Exar-Kun]

Except that if they've been on the sheflt, they would have to be turned anyway, since most rotors need to be turned to get the propper mating surface for brake pad bed-in..

sheeesh, "Enlighten the people generally, and tyranny and oppressions of body and mind will vanish like evil spirits at the dawn of day." Thomas Jefferson

Ala, get some good rotors and ahve them turned before you put them on, to ensure a good mating surface for your pads.

-Chet