Brakes Wheels 2nd Gen Tires Most liked posts in thread: Stock rotor backing plate - Yay or Nay?

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  1. Dr Obnxs

    Dr Obnxs New Member

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    #2 Dr Obnxs, Oct 17, 2009
    I've ditched them on most of my cars...

    I haven't seen any data. Some claim that they help keep rocks from getting jammed between the caliper/pad and the rotor, but I've never had issues. Some also claim that they keep heat from cooking ball joints and the like, but I've never seen data on that. The best cooling kits use backing plates to channel the cooling air into the center of the rotor. but the stockers look like they keep air out more than air in....

    But then, eventually I run out of brake and upgrade so they go away anyway.

    Matt
     
  2. Nathan

    Nathan Founder

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    #3 Nathan, Oct 17, 2009
    Or sadder that I came up with this...

    What do the backing plates do?

    Are they protection from road debris, but if so there is no fronting plate. They must have some needed purpose unless the entire auto industry has been hypnotized by a vast Backing Plate Mafia conspiracy.
     
  3. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    #4 BlimeyCabrio, Oct 17, 2009
    Matt, dude, I'm so disappointed that you haven't already run outside and started instrumenting a rotor to give me real data on this. Seriously. You're slipping.

    Maybe I need to get Dr. Phil fixated on this. ;)
     
  4. Dr Obnxs

    Dr Obnxs New Member

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    #5 Dr Obnxs, Oct 17, 2009
    Ever since...

    I've been worrying about Umlauts, I just haven't been able to get motivated!

    I'll try to do better.

    Matt
     
  5. Steve

    Steve Administrator
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    #6 Steve, Oct 17, 2009
    Mine are gone, but I'm not running stock brakes either.

    Here's a little somewhat related qualitative data. My Element has them front and rear and they're coming off when I do the brakes (this week, I think). I'd been hearing a lot of noise from the brakes and it got steadily worse through this spring (and it's still there) though there's plenty of pad left, etc. FYI - I would have dealt with the problem in the spring but the Element has basically been parked since then...and I procrastinated.

    I inspected all four corners last week and found all of them heavily damaged by rust, but only on the hub sides, i.e., behind the plates. There's very little clearance between the plates and the rotors plus the plates wrap around the edges of the rotors. This is the root of my completely unsupported theory involving winter ice-removal chemicals (or at least water) getting trapped behind the plates.

    Back to the question, I can't imagine there's any way for there to be as much air flow to the back of the rotors as there will be with the plates removed. Yes, some duct systems use plates as well, but that's intentional and designed to ensure the air being funneled toward the rotors is forced behind the plates and along the surface of the rotors instead of just adding to the general air flow in the area of the hub.
     
  6. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    #7 BlimeyCabrio, Oct 17, 2009
    I'm putting my mountain pads on in the next day or two (in preparation for MSSD) and will take the opportunity to shed the plates... as I've run the same caliper/pad/rotor/tire combo on the Dragon a couple of times previously, I'll see if I notice any substantial difference in brake fade or rotor temps next weekend.
     
  7. ScottinBend

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    #8 ScottinBend, Oct 17, 2009
    Are we talking about part #3...?
     
  8. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    #9 BlimeyCabrio, Oct 17, 2009
    yep
     
  9. ScottinBend

    ScottinBend Space Cowboy
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    #10 ScottinBend, Oct 17, 2009
    I always assumed it was to aid in cooling, kinda like the front wheel "spats" on the F1 cars now.
     
  10. quikmni

    quikmni Moderator

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    #11 quikmni, Oct 17, 2009
    Interesting question. I always figured the plates were more to keep debris away. I would think that more air would get to the rotors without the plates. I do not think that the vehicle manufactures are too worried about heat but instead more worried about debris. It would be an interesting test. But mine are already removed due to larger rotors.
     
  11. BThayer23

    BThayer23 Well-Known Member

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    #12 BThayer23, Oct 17, 2009
    I say lose 'em. I think they're supposed to keep rocks out of the calipers, but then again I used to think DSC would keep me on the track. =) There is some shape to the backing plates, like they should channelize airflow to and from the rotors, but everything's not really lined up. And btw, you get to use your tiny torx sockets for this one.

    I have this [entirely unsupported] theory that stock brakes are designed to hold heat, because stock pads rarely get up to temperature with the average driver behind the wheel. I mean, most people think the ABS sound is the car breaking (not braking). Those cast iron calipers are heavy, cheap, and hold heat like it's their job. It would make sense for the brakes to hold heat and maintain maximum stopping power in a panic stop, which most people do about once a year. If you're threshold braking on purpose, you're probably in the 95th percentile of drivers.
     
  12. AMG-RX7

    AMG-RX7 New Member

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    #13 AMG-RX7, Oct 18, 2009
    Besides debris, the backing plates also help keep the rotor dry when driving in the rain or through puddles. the first time I drove through a puddle w/o them on another car gave me a surprise. )
     
  13. Dr Obnxs

    Dr Obnxs New Member

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    #14 Dr Obnxs, Oct 18, 2009
    Last edited: Oct 18, 2009
    My lowly 75 Fiat 124 Spider

    backing plates had a lip angled to bring more air in. And more water, I guess.

    Matt
     
  14. Mike

    Mike New Member

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    #15 Mike, Oct 18, 2009
    My backing plates help cool the brakes, but only because I chopped them down and added an air duct. The backing plates do help to keep rocks from getting between the rotor and the caliper on stock brakes.
     
  15. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    #16 BlimeyCabrio, Oct 18, 2009
    Well, my plates are now removed. I also ground some deposits off my rear rotors that were left over from my last track day, and installed my Carbotech AX6 pads, and did a full flush and bleed. Cleaned everything up well with brake parts cleaner and re-lubed my slider pins.

    OMG, the car stops like you threw out an anchor. I forget how much I love the performance of the AX6 pads. Just wish they weren't so insanely dusty and I'd use them all the time on the street.

    We'll see how things go in the mountains without the backing plates.
     
  16. Sneedspeed

    Sneedspeed New Member

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    #17 Sneedspeed, Oct 19, 2009
    We have found on every car we have ever tracked, the backing plates cause the brakes to over heat. They are there to keep rocks, mud and water from hitting the brake rotor and causing problems. Unless your offroad rallying lose 'em.
     
  17. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    #18 BlimeyCabrio, Oct 19, 2009
    Good to know. After seeing (literally) the heat pouring off my rotors at the Dragon and the track, it seems that, if nothing else, they'd cool down better after you pull off without the plates behind them holding in heat.
     
  18. mini_racer

    mini_racer Well-Known Member

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    #19 mini_racer, Oct 19, 2009
    Would you get the best of both worlds if you were to incorporate a ducting system like your duct brackets, with the OEM backing plates? This way you get maximum cooling from the duct, the backing plates keeps the ducted air corralled around the rotor, and you also get debris protection.

    Maybe this is what was referred to above by Dr. Mike?

    Just a thought!
     
  19. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    #20 BlimeyCabrio, Oct 19, 2009
    Lots of examples of that setup on other cars - here's some of Turner's for the BMWs.

    [​IMG]
     
  20. mini_racer

    mini_racer Well-Known Member

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    #21 mini_racer, Oct 19, 2009
    Yes, that is it exactly. Seems to me that this is the perfect solution.
     
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