Brakes Rotor size question

derek1993 · May 16, 2021

Mounted up calipers and rotors today, looking at the coverage of the pad on the rotor face it looks like width of the face is made for a bigger/wider pad or setup?
Everything mounted up correctly, but just concerned about the amount of rotor not being used /touched. Triple checking part #s, etc.
Rotors are from r1 concepts

Mustang5L5 · May 17, 2021

Yes, it's normal for the 13" cobra setup to only have 2" or so of pad coverage on the face. Your setup is correct. It's just how it is.

That caliper was originally used in early 80's corvettes with a 12" rotor setup, so there wasn't much face to contact originally. In the 90's PBR redesigned the caliper to offer more pad sweep area for 13"-13.5" rotors and GM adopted it for the '97 Corvette. Ford stuck with the early caliper through 2004 and never made the change.

I actually run the new design PBR on my car. Baer used to make brackets for it, and it covers ALL of the rotor face which is what I like about it. Same piston sizes as the Cobra, but MUCH more pad area.

derek1993 · May 17, 2021

Mustang5L5 said:
Yes, it's normal for the 13" cobra setup to only have 2" or so of pad coverage on the face. Your setup is correct. It's just how it is.

That caliper was originally used in early 80's corvettes with a 12" rotor setup, so there wasn't much face to contact originally. In the 90's PBR redesigned the caliper to offer more pad sweep area for 13"-13.5" rotors and GM adopted it for the '97 Corvette. Ford stuck with the early caliper through 2004 and never made the change.

I actually run the new design PBR on my car. Baer used to make brackets for it, and it covers ALL of the rotor face which is what I like about it. Same piston sizes as the Cobra, but MUCH more pad area.

derek1993 · May 17, 2021

Thanks Mike, appreciate the information. Something to look at in the future then. I'll just need to quiet my OCD for a while (and swap the rotor since i realized once i took the pic that i had the wrong side on)..

Now to figure why the pad retaining pin was so tight.. probably need to take a small hole file and clean up paint a bit..

Mustang5L5 · May 17, 2021

You need to go by the internal vanes to determine rotor direction. My rotor in the above pic is on the same way, but it's the correct orientation due to the internal vanes.

derek1993 · May 18, 2021

Mustang5L5 said:
You need to go by the internal vanes to determine rotor direction. My rotor in the above pic is on the same way, but it's the correct orientation due to the internal vanes.

No directional vanes on these rotors (that i could tell), followed their guide.. All set now. Thanks again.. onto the next step..

7991LXnSHO · May 18, 2021

Mustang5L5 said:
Yes, it's normal for the 13" cobra setup to only have 2" or so of pad coverage on the face. Your setup is correct. It's just how it is.

That caliper was originally used in early 80's corvettes with a 12" rotor setup, so there wasn't much face to contact originally. In the 90's PBR redesigned the caliper to offer more pad sweep area for 13"-13.5" rotors and GM adopted it for the '97 Corvette. Ford stuck with the early caliper through 2004 and never made the change.

I actually run the new design PBR on my car. Baer used to make brackets for it, and it covers ALL of the rotor face which is what I like about it. Same piston sizes as the Cobra, but MUCH more pad area.

The bigger calipers look cooler.
Not a lot of the breaking work is done by the inner area of the disc. Surface area and mass are important (especially for heat exchange), but the distance from the hub determines a lot of the torque applied. Think of a 6” socket wrench vs a 2’ breaker bar - that change just made you 4x more foot pounds of torque on a rotational mass. (Like a bigger rotor.) Putting both hands near the end of the long handle to pull will do more than spreading them apart across the breaker bar.
Now, if you get mad like Bruce Banner and have a Bill Bixby to Lou Faringo transformation, (bigger and stronger calipers and brake pads), you can clamp down on more of the breaker bar and change the angular momentum even faster.
The bigger calipers are better for heavier use. But if you are not seeing track time, I wonder if they are worth the extra weight, fitting hassle and cost. Also, will your cat’s shoes still fit? It seems the Hulk ended up loosing his shoes in every episode.

Brakes Rotor size question

derek1993

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That is…until I whipped out my Bissell

derek1993

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derek1993

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Mustang5L5

That is…until I whipped out my Bissell

derek1993

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7991LXnSHO

wanna catch the space herp

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Brakes Rotor size question

derek1993

Active Member

Attachments

Mustang5L5

That is…until I whipped out my Bissell

derek1993

Active Member

derek1993

Active Member

Mustang5L5

That is…until I whipped out my Bissell

derek1993

Active Member

7991LXnSHO

wanna catch the space herp

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