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Any case law/historical valuation on 2 pc rotors?


pintodave
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As the title states: any historical valuation data on 2 pc rotors? OEM diameter and thickness.

 

Back ground:

I'll elaborate more later (with pictures!)... But I think I discovered why we are occasionally and randomly thrashing rotors. Definitely a quality issue (from China with love). I am assuming that both 'white box' raybestos and centrics are probably coming out of the same factory. Discovered rotors coming with a huge core shift issue. .060 measured difference per face, so that is a .030 shift. Also crack seems to propagate at a cast-in letter/feature located on the inside of the vein. 

 

First thing I am going to do is hit a bunch of parts stores with my calipers and see if this is an epidemic across all sources or just a random issue. Then come up with plan B as needed.

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I would expect this to be a very straightforward answer...if they fall within 2x pricing for stock rotors, they are legal. 

That being said, I think you'll have a hard time finding a 2-piece rotor that falls within that range. Good luck!

S. 

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Oh I know they will not be within 2x (although the replacement rotor sections on the other hand.....) 

 

I'm curious if they were assigned a flat rate or ???? You have a "performance advantage" from the perspective of you'll still be on track because you didn't explode a rotor, but if there is no size advantage and thus no increase of braking performance capacity, then it turns into "that grey area" that needs to be turned over to a committee for a solid ruling that all teams can have for reference.

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2 hours ago, pintodave said:

no size advantage and thus no increase of braking performance capacity

No size advantage but you get the benefit of more thermal shedding via well controlled vain casting/ design, something the one piece guys will never achieve...

 

You will find difference between manufactures/countries of origin, hint #1: stay away from autozone, lifetime warranty means squat when cooling design is nowhere near priority.

Ask me how I know.

Edited by Team Infiniti
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3 hours ago, pintodave said:

Oh I know they will not be within 2x (although the replacement rotor sections on the other hand.....) 

 

I'm curious if they were assigned a flat rate or ???? You have a "performance advantage" from the perspective of you'll still be on track because you didn't explode a rotor, but if there is no size advantage and thus no increase of braking performance capacity, then it turns into "that grey area" that needs to be turned over to a committee for a solid ruling that all teams can have for reference.

But there is an increase in braking performance capacity. You have better cooling as well as insulating the hub/wheel bearing from the heat (especially with an aluminum hat) created during braking much, much better than a one-piece rotor, lighter weight and more stable thermal characteristics. 

So I'd argue that there is a performance increase, and if they are NOT under the 2x rule they should be worth points. Probably not the opinion you want to see, lol. 😉

S. 

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Lol I honestly don't care what you call it, I just don't want to see a rotor explode, and was trying to see what/if anyone had it ruled for previously regarding Chump/Champ points.

 

I'm not a road racer with experience with these types of components, if there is a performance advantage it is unknown to me. I would assume a performance advantage with an aluminum hat, for weight if nothing else. I get that point. Thus why I would assume there is a penalty. 

 

The captain obvious point of the rotor not exploding could be construed as a performance advantage 😂

 

 

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Pictures!

 

So, unknown to me until this afternoon of post-test Sebring inspection - here is the LF rotor from the Sebring test. No heat checks, no issues, no nothing. Just a huge ass crack. Rewind to Daytona a couple months ago..... same corner had an issue with a large crack. RF looks pristine. 

 

Note issues in following pics:

- location of emboss and fracture

- imbalance of material (core shift), again .060 total, .030 per side

 

odabwIAIdrLh0A1ufVODrM3VwnYmOvHJPU1JAnFj

qOgMogUR96CmjF0lUpQF2_0H2l34FJ9EoAublpVD

 

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Beats me man.... this set is with the Wilwood calipers. Interestingly enough, no embossed letters in the RF rotors (not there at all, they dont exist). RF rotors are perfect with thickness balance, both .310 thk. 

 

Edit: I'll go on a rotor hunt tomorrow........

 

Double Edit: have you taken your worst rotors and run them on your Champcar, or are we talking street application?

 

Triple edit: brake lathe would not matter... measured at 12, 3, 6 9 o'clock... shizzzz is thick one way vs the other.

 

Edited by pintodave
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2 minutes ago, pintodave said:

Beats me man.... this set is with the Wilwood calipers. Interestingly enough, no embossed letters in the RF rotors (not there at all, they dont exist). RF rotors are perfect with thickness balance, both .310 thk. 

 

Edit: I'll go on a rotor hunt tomorrow........

 

Double Edit: have you taken your worst rotors and run them on your Champcar, or are we talking street application?

 

Street and shark, to date, no rotor has ever been condemned based on shift, commented on, yes, discarded, no.

 

 Saying That:

 

For the last 5ish years the sharks rotors come from our local parts house, white box, $30ish, china, no inspection or prep past squirting with brake cleaner. Prior to this, due to severe shuddering/cracking, each rotor was endlessly fussed with, diameter cut slightly on a brake lathe, runout checked/corrected/rotor clocked, raced, runout rechecked etc... Turns out, in our case, it was pad selection not a rotor issue.

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1 hour ago, pintodave said:

Lol I honestly don't care what you call it, I just don't want to see a rotor explode, and was trying to see what/if anyone had it ruled for previously regarding Chump/Champ points.

 

I'm not a road racer with experience with these types of components, if there is a performance advantage it is unknown to me. I would assume a performance advantage with an aluminum hat, for weight if nothing else. I get that point. Thus why I would assume there is a penalty. 

 

The captain obvious point of the rotor not exploding could be construed as a performance advantage 😂

 

 

Well aren't you just a grumpy bug tonight!

S. 

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2 hours ago, pintodave said:

Pictures!

 

So, unknown to me until this afternoon of post-test Sebring inspection - here is the LF rotor from the Sebring test. No heat checks, no issues, no nothing. Just a huge ass crack. Rewind to Daytona a couple months ago..... same corner had an issue with a large crack. RF looks pristine. 

 

Note issues in following pics:

- location of emboss and fracture

- imbalance of material (core shift), again .060 total, .030 per side

 

odabwIAIdrLh0A1ufVODrM3VwnYmOvHJPU1JAnFj

qOgMogUR96CmjF0lUpQF2_0H2l34FJ9EoAublpVD

 

 

I can't see your pictures but always LF says a lot.  Is there a dead gopher in that duct, something blocking it, outlet angled poorly?  Isn't there a generation of Corvette that always blows out the rotor on one corner because the vanes were manufactured the wrong way?

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7 hours ago, Ron_e said:

 

I can't see your pictures but always LF says a lot.  Is there a dead gopher in that duct, something blocking it, outlet angled poorly?  Isn't there a generation of Corvette that always blows out the rotor on one corner because the vanes were manufactured the wrong way?

 

Interesting thoughts, I will look at the duct today. No damage to screen so I would assume no, but worth looking. Vanes appear to be correct, but again, that is worth some google research. 

 

Per previous comments from @Team Infiniti regarding brake cooling and air flow I do think I'll be moving my ducts inwards about 10" to improve the flow (was going to do that even before this discovery).

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2 hours ago, pintodave said:

 

Interesting thoughts, I will look at the duct today. No damage to screen so I would assume no, but worth looking. Vanes appear to be correct, but again, that is worth some google research. 

 

Per previous comments from @Team Infiniti regarding brake cooling and air flow I do think I'll be moving my ducts inwards about 10" to improve the flow (was going to do that even before this discovery).

 

A screen on the duct inlet will reduce air flow, thus cooling as well.

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Yea, but I don't want any dead gophers in there :lol:

 

So, of the 4 local parts stores, only AutoZone and Advanced had them in stock. I'd say the AutoZone house brand looked better than the Advanced white box. Measured a little more consistent, although neither was as bad as what I currently have. 

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We run Advanced or Autozone "high Carbon" rotors and haven't had an issue.  We had some light radial cracking, mostly cosmetic.  We do run 3 inch brake ducting that terminates on the wheelbearing/inside of the hub.  Never had an issue with vibration or runout..We just junk them after every race...

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So I've come to the conclusion that I'll be running:

 

1. plain white box Centrics (not high carbon, nothing fancy), I've used these once or twice from RockAuto, do not recall anything detrimental beyond heat checking and some warping, not good for more than one event

2. AutoZone rotors, as they looked reasonably well made, could tell by vane casting they are made in a different China factory 

3. Anyone have any experience with the Raybestos R300 line? Don't care for the slotting, but focusing on materials and construction, surprisingly cost effective from RockAuto

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5 hours ago, Black Magic said:

I bet you could use stock rotors as the center, drill the holes for the bobbins carefully and use wilwood rotors under 2x cost. 

 

That said, has to be another rotor in the world from an oem application that will fit what you need.....

 

Now that is creative thinking. I like it. Not going to get around to that much craziness before VIR, but vewy vewy interesting..... 

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