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Lightweight rotors?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by a_gray_prius, Jun 26, 2014.

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  1. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    Does anyone know of a manufacturer that makes a lightweight rotor for gen2 figment? Its time for me to get my brakes done and I'd like to lose some rotating mass while I'm at it.
     
    #1 a_gray_prius, Jun 26, 2014
  2. xliderider

    xliderider Senior Member

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    You can try sourcing cross drilled rotors, but you would be better served searching for light weight rims because they are larger in diameter. Therefore they would have a larger effect.

    SCH-I535
     
    #2 xliderider, Jun 26, 2014
  3. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    I already run Volk CE28n Eco Drive rims, one of the lightest rims that you can buy. I'm just looking to further reduce unspring weight.
     
    #3 a_gray_prius, Jun 26, 2014
  4. Easy Rider

    Easy Rider Active Member

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    Why ?

    Are you going to be drag racing where thousands of a second makes a difference ?? Seriously.

    And unless you pay a LOT for really high quality racing rotors, a lighter one often also means that they will be weaker too.

    What indication do you have that the rotors even NEED to be replaced ??
     
    #4 Easy Rider, Jun 27, 2014
  5. NortTexSalv04Prius

    NortTexSalv04Prius Active Member

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    I am curious what the specification of Volk(dia size, weight, and material used.) I have a Gen2 Prius with stock OEM 15 inch aluminum rim. In the past when ask others pc members about the custom rims I get the following responses ....not 15 inch rim,,,,cost vs weight saving not there....
    Anyway
    I have consider the rotors that litebrake.com (steelclad alum rotors) that can be purchased from website.
     
    #5 NortTexSalv04Prius, Jun 27, 2014
  6. blurred

    blurred New Member

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    If you want light weight contact Coleman racing. They will build you a custom set of 2-PC rotors, the aluminium hat will save a few pounds and if you want to ruin the rotor you could have them cross drilled as well for a few ounces that you can't notice.
     
    #6 blurred, Jun 27, 2014
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  7. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    They probably don't. But I'm getting the work done and I figure since the brakes are going to be serviced anyway I might as well.

    The Volks weren't purchased with any intention of cost savings in mind. Cars are my hobby, and I felt like it.

    Here is information about the CE28N Eco Drive: Volk Racing CE28 Eco Drive Wheels for Prius Only! | PriusChat

    I'm not a big fan of cross-drilled rotors for street cars - too much risk of cracking. That said, there's an SAE paper from 2006 where some engineers from GM evaluated the effects of different brake rotor treatments (cross-drill, slots, etc) that's pretty intersting: The Effect of Rotor Crossdrilling on Brake Performance
     
    #7 a_gray_prius, Jun 27, 2014
  8. jzchen

    jzchen Newbie!

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    Since you seem to have expensive taste maybe you could ask rotora if they could produce some carbon ceramic ones....

    SCH-R530M ?
     
    #8 jzchen, Jun 27, 2014
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  9. 69shovlhed

    69shovlhed Surly tree hugger

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    Mercedes seems to be very impressed with drilled rotors cause most of the rotors on their cars and suv's for the last decade have them. I've never seen a MB rotor cracked from being drilled. if one was cracked it was from being beyond worn out. I did get some drilled rotors from ebay and they're zinc plated so they haven't turned into a rusty mess like the oe rotors did after 180k miles. I could have had them machined, but the ebay rotors and pads were cheap enough it wasn't worth it. and they work fine with very infrequent squeal after sitting in the rain for a couple days. honestly the oe rotors aren't heavy anyway. these are pretty small rotors so it would be a complete waste of time and money to look for anything lighter than oe. but the drilled zinc plated rotors do look pretty cool. I aught to paint my calipers.
    [​IMG]
     
    #9 69shovlhed, Jun 27, 2014
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  10. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    Haha - if I'm shilling out for carbon ceramic, then they're going on our Tesla. That said, quite a few people have had really bad experiences with Rotora's quality. Hypothetically, if I were to lay down that kind of coin, I'd get a Brembo system or adapt an OEM kit from a Porsche or something.

    When I went to Green Drive Expo in Madison WI a number of years ago, a guy turned up from Georgia (I think) with cross-drilled and slotted rotors behind Volk RE30 Super Ecos. It was a little too show-car-y for me. The fact that the rotors are pretty rusted is kind of one of the reasons I want to replace them, even though they could probably just be resurfaced just fine.

    I'm a little surprised at the amount of hate I'm getting over this. Reducing rotating mass isn't like some completely stupid mod. Given the long brake life and braking characteristics of the car, it's not like I'll likely have to deal with the consequences of reduced heat capacity from less rotor material.

    EDIT: They were RE30s not TE37s
     
    #10 a_gray_prius, Jun 28, 2014
    Last edited: Jun 28, 2014
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  11. 69shovlhed

    69shovlhed Surly tree hugger

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    some folks are afraid of change and thinking outside the box. but once you get a rotor in your hand, you'll see how light they are.
     
    #11 69shovlhed, Jun 28, 2014
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  12. jzchen

    jzchen Newbie!

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    No hate, my post came out the wrong way....

    Cross drilled/slotted, usually means a cooler running rotor, I can't say for sure but you might start to hurt your regenerative braking...
     
    #12 jzchen, Jun 28, 2014
    Last edited: Jun 28, 2014
  13. Easy Rider

    Easy Rider Active Member

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    And I'm constantly surprised by the number of people who seem to want to turn a completely innocent discussion into an argument.
    Just because a few of us are asking about your motives and reasoning and throwing out other ideas does NOT amount to "hate".

    Two points (not hate, incidentally):

    I think what you propose to do is just a waste of money; only slightly less of a waste if the rotors really need to be replaced.

    The brakes on a hybrid don't typically get a lot of use because of the regen braking. Because of that, they tend to develop "surface rust" whick quickly rubs off with a couple of hard stops.

    If you think everybody who expresses the least bit of disagreement with what you think is expressing "hate" then you need an attitude adjustment. And that statement is not "hate" either.
     
    #13 Easy Rider, Jun 28, 2014
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  14. jzchen

    jzchen Newbie!

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    I'm not sure but I thought heat from the rotors was converted into electricity as well...
     
    #14 jzchen, Jun 28, 2014
  15. Easy Rider

    Easy Rider Active Member

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    What exactly led you to believe that ?
    And how do you think it would be accomplished ??
    It's not true.
     
    #15 Easy Rider, Jun 28, 2014
  16. jzchen

    jzchen Newbie!

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    Thought I saw that somewhere, but I guess not. I'll shut up now.... :(

    SCH-R530M ?
     
    #16 jzchen, Jun 28, 2014
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  17. 69shovlhed

    69shovlhed Surly tree hugger

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    after 180k, my rotors had a lot of rust, and were pitted. there was just a thin band of unrusted contact patch around the middle of the rotor. changing rotors on these cars is very easy, and drilled rotors with pads were only about $80. I figured Wth, lets go for some better looking rotors. how can you go wrong at that price. pretty impressive that the oe pads lasted 180k, and still passed VA inspection when I replaced them.
     
    #17 69shovlhed, Jun 28, 2014
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  18. MarcSmith

    MarcSmith Active Member

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    fwiw I think BMW MB and Porsche cast their rotors with holes, not cross drilled.
     
    #18 MarcSmith, Jun 28, 2014
  19. Easy Rider

    Easy Rider Active Member

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    Pitted and worn unevenly after 180K miles is quite a different story.
     
    #19 Easy Rider, Jun 28, 2014
  20. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    Yeah, I couldn't find any information about how much the stock rotors weighed unfortunately. If I replace stock for stock, I'll be sure to weigh them for posterity.

    Don't feel bad. You're right, but a little confused. At the most basic level, brakes turn kinetic motion of the car into heat though the friction of brake pads across some braking surface. For disc brakes, this heat is captured by the rotor and dissipated into the air over time (hence the cooling vanes in most discs). This is why there are such large rotors in most racing applications - the repeated hard stops means that the disc material has to soak up all that heat, and when they are at capacity, the brakes start to lose effectiveness. That is one of the downsides of lightweight rotors - many of them simply have less rotor material to absorb heat (temporarily!). However, because the Prius has regenerative braking in which case much of the energy is recaptured (as opposed to being lost as heat in a traditional application), the brakes will on average run quite a bit cooler. So your understanding is somewhat correct, but needs some clarification; the heat that would otherwise be lost to the environment through friction braking is converted to electricity by the HSD. Since less energy gets transferred to the rotors in the form of heat, decreased rotor mass has less of an impact on braking performance.

    Dude, lay off the coffee a little. You're criticizing everyone and making a lot of assumptions about the condition of my car. There's a difference between a congenial discussion and a heated argument, and I'm trying to have the former while your posts are unfortunately making it more like the latter.

    Here's a couple pictures of my rotors (and the wheels I desperately need to clean). They're maybe savable, but in this condition I might as well replace them.
    [​IMG]

    [​IMG]
     
    #20 a_gray_prius, Jun 28, 2014
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