Raybestos Rotors?

[strat61caster]

Originally Posted by churchx

I'd really would like to find out WHAT really is causing differences between (almost same to my eye) rotors though :/

Test methodology, without data for brake pressure and vehicle speed over the stop it's hard to prove that they were put through the same test. Ideally you'd have temperature of the brakes as well as the cooling air over the duration of the stop. You can then integrate that to roughly approximate how much energy was put into the brakes over the duration, quantify any cooling effects (maybe the breeze was blowing a different direction? Or no breeze at all on one night), and arrive at a thermal capacity for each option.

Far too many variables and not nearly enough data or delta between results to draw any strong conclusions from this test.

[solidONE]

Originally Posted by churchx

I'd really would like to find out WHAT really is causing differences between (almost same to my eye) rotors though :/
I guess, very few did comparisons between oem replacement rotors that (almost obviously) should be same so didn't bother, material same iron, vanes count & shape almost same, so what is the culprit? :/ If there would be any difference in finish, it should quickly equalize after heavy brake use/bedding imho.
Almost as if it might be worthwhile to test all available oem rotor options out there for maybe even more unexpected surprises and/or to know more what to expect of supposedly known products.

I wouldn't be so sure that the metallurgy is identical. If you're willing to spend the time and money to test them out, please have at it. I've enough experience and played with it enough to know where I'll spend my money next time I'm replacing rotors.

Originally Posted by strat61caster

Test methodology, without data for brake pressure and vehicle speed over the stop it's hard to prove that they were put through the same test. Ideally you'd have temperature of the brakes as well as the cooling air over the duration of the stop. You can then integrate that to roughly approximate how much energy was put into the brakes over the duration, quantify any cooling effects (maybe the breeze was blowing a different direction? Or no breeze at all on one night), and arrive at a thermal capacity for each option.

Far too many variables and not nearly enough data or delta between results to draw any strong conclusions from this test.

And for the very reason what is required for "indisputable" proof to satisfy the critics who thinks that there is no difference between the rotors even when presented with data that says otherwise. But.., you're 100% right. There are too may variables in play. We'd need a machine to use exactly the same pedal pressure, test under the same exact ambient temps and conditions with exactly the same pad material that are ideally brand new for each test, with exact same applied force for the exact same duration of time.

Again.. I'm curious as well but not curious enough to invest the time effort and money to produce data that will satisfy everybody. It is what it is lmao

[strat61caster]

Originally Posted by solidONE

We'd need a machine to use exactly the same pedal pressure, test under the same exact ambient temps and conditions with exactly the same pad material that are ideally brand new for each test, with exact same applied force for the exact same duration of time.

Not really, you'd just need accurate data to eliminate the variables you can't control and focus on the physics of what's actually happening: kinetic energy to heat, brake pressure would have just been a nice to have to verify consistency and in hindsight not terribly relevant.

Speed, temperature over time at a couple different locations and some hand wavey math would probably get the job done pretty well and bore 95% of the readers to death. :P

I mostly posted that to try and calm down @churchx your data is totally reasonable and I'm glad you did it. As always people will draw what conclusions they will.

[solidONE]

Originally Posted by strat61caster

Not really, you'd just need accurate data to eliminate the variables you can't control and focus on the physics of what's actually happening: kinetic energy to heat, brake pressure would have just been a nice to have to verify consistency and in hindsight not terribly relevant.

Speed, temperature over time at a couple different locations and some hand wavey math would probably get the job done pretty well and bore 95% of the readers to death. :P

I mostly posted that to try and calm down @churchx your data is totally reasonable and I'm glad you did it. As always people will draw what conclusions they will.

I dont think he questioned the testing methods or results, but rather why there is a difference in the results between something that is supposedly the same lumps of metal and should have no difference in performance.

While the minor difference between the 100-0 test may or may not be explained away by the lack of precise control of the pressure I put on the brake pedal, and as similar as these rotors seem to be there are differences that don't seem like they'd be a big deal. There may be things about them different that is worth considering. One had anti-rust coating, the other doesn't. The castings are very similar but definitely not identical. The base metal used is probably not from the same foundry and there's probably differences in the composition of the metal. All of these things may contribute to the heat retention or dissipation characteristics.

I'm not willing to invest any more time to investigate further than I've already. If someone else would like to do so I would be glad. Otherwise... "it is what it is.. "

[strat61caster]

Originally Posted by solidONE

I dont think he questioned the testing methods or results, but rather why there is a difference in the results between something that is supposedly the same lumps of metal and should have no difference in performance.

I spent a few months performing thermal tests for work, based on the data and test methodology you presented, imho your test is inconclusive and the results are not significant enough to draw any conclusions.

[solidONE]

Originally Posted by strat61caster

I spent a few months performing thermal tests for work, based on the data and test methodology you presented, imho your test is inconclusive and the results are not significant enough to draw any conclusions.

Edit: I was going on about my hand wavy maths and the +100*f difference in front rotor temps doing the downhill runs. Then I realized I don't want to do any more deliberate testing of these OE replacement rotors.

Since you have the expertise.. would you test them out using what you'd consider acceptable methodology? What rotors are you running now?

[strat61caster]

Originally Posted by solidONE

Edit: I was going on about my hand wavy maths and the +100*f difference in front rotor temps doing the downhill runs. Then I realized I don't want to do any more deliberate testing of these OE replacement rotors.

Since you have the expertise.. would you test them out using what you'd consider acceptable methodology? What rotors are you running now?

lol

I'm still on oem after 70k miles, but they're probably due to be replaced this summer. If you read back on my earlier posts I'm off the opinion any reputable brand will offer a comparable lump of metal and I have no interest spending several hundred dollars (hell maybe thousands to get what I would actually trust) and dozens of hours setting up a test. I'm glad you did yours, it's neat, but it's easy to see 10-20 degrees of unexpected results in even tightly controlled thermal tests in isolated chambers, put a test out in the wild without accurately measuring your environment? I'm only looking at your test with the 1x and 2x 100-0 stops, you don't see a difference greater than 15 degrees between the different front rotors.

I'll cross shop the raybestos and centric and buy whichever is cheaper.

[solidONE]

Originally Posted by strat61caster

lol

I'm still on oem after 70k miles, but they're probably due to be replaced this summer. If you read back on my earlier posts I'm off the opinion any reputable brand will offer a comparable lump of metal and I have no interest spending several hundred dollars (hell maybe thousands to get what I would actually trust) and dozens of hours setting up a test. I'm glad you did yours, it's neat, but it's easy to see 10-20 degrees of unexpected results in even tightly controlled thermal tests in isolated chambers, put a test out in the wild without accurately measuring your environment? I'm only looking at your test with the 1x and 2x 100-0 stops, you don't see a difference greater than 15 degrees between the different front rotors.

I'll cross shop the raybestos and centric and buy whichever is cheaper.

Well.. in case you change your mind by the time you replace your rotors. I've both brand front rotors at close to original thickness above 23.8mm. If you get the Raybestos I'll send you my Centrics. I'm actually curious enough to send these over to you if you're willing. Shouldn't cost too much to ship a set of rotors from LA to the Bay. lol

[solidONE]

2 years later. Currently running and almost through with the stoptech and my 25% of the original HC800+ before these went on.

Hard runs in the canyon does not phase it as badly compared to Centric + Stoptech or HC800+. I can almost do an extra run up and down that road before it starts to fade (10-15minute-ish run).

Not sure how they are priced now, but I would definitely recommend these over Centric any day of the week, if they cost only a few bux apart.