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Options for 13.1" (335mm) Rotors

13K views 38 replies 8 participants last post by  20focusSTdriver17 
#1 ·
So I ordered rotors and pads for my upcoming track day.

Centric Sport Rotors Front
Centric Rotors Rear
Hawk DTC-30 Front Pads
Hawk HPS Rear Pads

I was going to make some air scoops from some Kydex then after opening the new front rotors I noticed an issue.

The 13.1" (335mm) OEM rotors have the opening for the venting at the hub facing out towards the wheel. This makes it hard to get fresh cool air into the hub for the rotors from any air scoops or brake ducting.

Well when I opened the new StopTech/Centric rotors I noticed they followed the OEM design which is a bummer. I checked photos of the Slotted StopTech and they are designed the same way. And apparently PowerStop, EBC, Hawk don't have any listed part numbers for the 2014.5+ (13.1") rotors.

Here is a photo of what I am talking about (PN# 125.65146)
Disc brake Metal Automotive wheel system Rim Wheel
 
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#2 ·
I'd just get the air deflectors that I think Velosatech makes. I believe they are the ones that did research at the track measuring temps and had an improvement.

As far as rotors, I would use what ever was cheapest at Advance Auto Parts. They have always worked as good as any other rotor on my track dedicated Mustang and when they crack I get them replaced under warranty.
 
#4 ·
Don't spend a lot of $$$ on fancy rotors. Like hopper said, blanks are best.


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Both you guys missed the point of the post. I didn't buy some fancy slotted rotors. I bought the Centric Sport rotors which are basic high carbon vented rotors.

The point is that the Centric/StopTech rotors vent on the outside towards the wheel. Which means the Air scoops/etc are less effective.
 
#5 ·
No, I got your point. Sounds like what you're saying is the OE design doesn't have the vent opening at the center and on the inside of the rotor and that is how the aftermarket is making them also. I can't confirm or deny cause I have not looked on my own car. But either way if that is how it is made you have to work with what you have. So make or get air deflectors to blow toward the rotor. Better than nothing.
 
#6 ·
Unfortunately air scoops wouldn't do much on a 2014.5+ from the way it looks with these rotors. First you have a dust shield that is blocking the back of the rotor. Second you don't have vent openings in the hub area so fresh air would have a very small area to help cool.
 
#7 ·
If you're using it on the track then the dust shields should be removed anyway. You just have to make the best out of the system you have to work with. Good luck with it.
 
#9 ·
It is not that it isn't helpful. I was referring to the idea of them not showing as big as gains as a rotor that vents towards the inside (hub side)
 
#10 ·
Bump

Unfortunately even shopping for rotors is fun since alot of stores and brands want to list they make rotors for the 2014.5+ models and then you look and they are only 320mm sized rotors.
 
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#12 · (Edited)
This is what I've been finding 2+ years later too! LOL

Disregard my last post since I don't even think the 2 piece 332x32 Aerorotors in that ST40 kit are available as a standalone purchase or fit the stock calipers and they may have the same vent design as the ones you bought from centric, although they should have improved cooling per the marketing literature and cost. Someone else also posted the OEM 18" wheels don't clear the ST40 calipers, not sure if spacers were a viable or worthwhile fix.
 
#11 ·
#13 ·
Anybody know the thickness/dimensions for new oem 13.1 ST rotors (332 x ?) and the thickness for the oem 13.7 RS rotors (350 x ?)?

Thanks
 
#17 ·
#18 ·
so next question is what is the max rotor thickness the stock calipers can fit??
 
#20 ·
I wonder if there is a different bracket we can use (Mazda?) in order for the front oem ST calipers to accept the bigger 350mm RS 13.7" rotors>>> Frankenbrake Front????? :smile:

or would there be a oem wheel clearance issue similar to the Brembos??
 
#21 · (Edited)
so here are the outer RS Brembo caliper dimensions from a thread on RS.org, If I can find the OEM ST caliper dimensions we can compare but still need the max width between pads for max rotor thickness.

Diagram Parallel
 

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#23 ·
You should be a RS Brembo salesman!

I'm actually seriously considering changing my wheel arrangement so I can get the RS Brembos. It just makes more sense considering the 4P performance upgrade, better rotor options & cost plus keeping the frankenbrake bias closer to spec.
 
#29 · (Edited)
I considered that! lol That was going to be my next measurement calculations once I confirmed caliper fitment. hey man you're really being a Debbie downer here!! haha

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#30 ·
maybe I am not thinking straight but.... if you have a bigger rotor but don't have bigger caliper and pads you will have the same contact patch as the stock rotor. I would think you need to increase the size of both in order to get full benefits? not even sure how bigger rotor would help, just increased rotating mass?
 
#31 ·
Bigger calipers would be better but it would be no different than going from the 12.6 rotors (320mm) on <2014.5 model years to the 13.1 rotors (332mm) the 14.5'+ current models have, all have same calipers. Same deal with the frankenbrake rear, bigger rotors same calipers. I understand your argument but it would apply to the other scenarios too??

I would think bigger rotors have better heat dissipation, I think they call it thermal something or other..
 
#32 · (Edited)
also depends on the rotor.. I can get slotted DBA 4000 T3 for the 350mm RS size which probably have same weight as stock 332mm ST rotors. Ill check again but im sure there are many more rotor options available in the 350mm size vs the 332mm
 
#34 ·
DBA T3 4000 Series T-Slot Slotted Rotor - DBA 42968S 350x25mm - Item weight: 25lbs - Focus RS
 
#36 ·
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#37 ·
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